Ten Percent Happier with Dan Harris - 221: All Your Sleep Questions, Answered | Dr. Matthew Walker

Episode Date: January 8, 2020

Dr. Matthew Walker is a sleep scientist with a PhD in neurophysiology. His research investigates the impact of sleep on human health and diseases like Alzheimer's, Parkinson's, and cancer. In this episode, Dr. Walker shares significant findings on what happens to us when we do not get enough sleep. He also offers practical tips on how we can get more, quality sleep and how meditation can help. Join the New Year's Meditation Challenge: https://10percenthappier.app.link/IpETZ7CAX1 Plug Zone-- Book: Why We Sleep, https://www.amazon.com/dp/1501144316 Website: https://www.sleepdiplomat.com/ Twitter: https://twitter.com/sleepdiplomat?lang=en Podcast Insiders Feedback Group: https://10percenthappier.typeform.com/to/vHz4q4 Have a question for Dan? Leave us a voicemail: 646-883-8326 See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Before we jump into today's show, many of us want to live healthier lives, but keep bumping our heads up against the same obstacles over and over again. But what if there was a different way to relate to this gap between what you want to do and what you actually do? What if you could find intrinsic motivation for habit change that will make you happier instead of sending you into a shame spiral? Learn how to form healthy habits without kicking your own ass unnecessarily by taking our healthy habits course over on the 10% happier app. It's taught by the Stanford psychologist Kelly McGonical and the Great Meditation Teacher Alexis

Santos to access the course. Just download the 10% happier app wherever you get your apps or by visiting 10% calm. All one word spelled out. Okay on with the show. For ABC, this is the 10% happier podcast. I'm Dan Harris. Hey guys, we got a sleep bananza for you this week. Big media episode, we're going to have answer all your questions about sleep, which is a huge issue. Before we dive in, three items of business.

One, there is still time to join our 10% happier January meditation challenge. Two days left to join the challenge. Friday, the 10th of January is the last day to sign up. You can follow me and one of our star meditation teachers, Alexis Santos in the challenge. You can sign up through the app. Second thing to point out, since we're doing our sleep anands of this week, that if you check out the app itself, we have a whole meaty section of the app dedicated to sleep.

And we hear from a lot of users about how helpful that is. And the third thing to point out is that the voice mails this week are going to be answered by Orange Asofer, another really popular meditation teacher on the 10% happier app. And Orrin has recorded many of our most popular meditations for sleep. So he'll be answering sleep-related meditation questions at the end of this episode. Okay.

So our guest this week is Dr. Matthew Walker who earned his neuroscience degrees over in the UK and then became a professor of psychiatry at Harvard Medical School And we're doing a two-part episode this week. In the first part, we're talking about all the things, all the unfortunate things that can happen to you when you don't get enough sleep to your heart, to your brain, to the other parts of your body. We're talking about the link between sleep and mental health, what kind of impact meditation can have on sleep and the stigma, what kind of impact meditation can have on sleep, and the stigma in our society around sleep. And then we, so we did an hour together on that several months ago, actually, we first recorded that first hour, and then we took a couple months break, and I started

to wear a sleep tracking ring. And so we go back to Matthew for another chunk of this interview where we talk about my data and many other questions that are fascinating. So here we go with part one of the interview with Matthew Walker on Sleep. It's a pleasure to meet you. I kind of feel like I know you after having listened to somebody podcast. Well, likewise too, I have to say. So yeah, our relationship goes by gears at the stage. This is great.

Nice to see all friends. You have had, as I was saying to you earlier, you really had an impact in the way I think about sleep, so I'm excited to pass that along to our listeners and viewers. So let me just ask some biographical stuff. How did you get interested in sleep in the first place? I don't think anyone, you know, when they're five or six years old and you go around the classroom and say, what would you like to be when you grow up? No one shoots the hand of them, so I'd love to be a sleep researcher. And I think we're all accidental sleep researchers. And I was the same. So back during my PhD work, I was looking at

brainwave patterns in people with dementia, early stages, and I was trying to differentially diagnose what form of dementia that they had was it, sort of vascular dementia or Alzheimer's disease, and was failing miserably. I used to go home at the weekends with the stack of journals and I put them in my doctor's residence. It's like a little igloo of information around me. And when, I was reading that some of the centers that certain types of dementia would eat a way out in the brain were sleep-generating centers. And then for other types of dementia, they left those centers untouched. So I thought, well, I'm measuring the brainwave pattern of my patients at the wrong time, which is when they're awake. I should be measuring it

when they're asleep. Started doing that, got great results, and at that point I thought, maybe the sleep disruption is not just a symptom of the dementia. I wonder if it's actually a causal trigger. And that's when I just fell headlong into this field of sleep research. And at that time, no one could answer the question, why do we sleep? This is 20 years ago. The crash answer was that we sleep to cure sleepiness, which is that the fact you're a equivalent of saying you eat to cure hunger, it tells you nothing about the biological benefits of nutrition. We really do nothing about why we sleep. 20 years ago, we just had very little understanding other than that it was deathly if you removed it.

And they did these studies, some studies that probably will never be replicated again for ethical reasons in rats. And they decided to deprive the rats completely of sleep. And what they found was that those rats would die as quickly from sleep deprivation as they would from food deprivation within about 10 or 11 days. And so we were only on the cusp of realizing how fundamentally necessary sleep was. I then thought, well, if nobody knows it right now, I'll just come along and for two

years I'll go to America and I went to Boston and I thought, I'll crack that question. With total naivety, not hubris, not realizing that some of the most brilliant minds had failed to crack the question. And as I said, that was 20 years ago and I think hard lessons, a little about who asks them, they will meet or out their lessons of difficulty all the same. And I've been schooled over the past 20 years. So what do we know about why we sleep? Well, it's fascinating over the past 20 years we've had an explosion of knowledge.

In fact, we've had to upend that question. Rather than saying, you know, why do we sleep? We've now had to ask, is there anything that sleep doesn't serve in terms of a benefit for either the brain or the body. And the answer seems to be no, there is no single tissue within the body, nor process of the mind that isn't wonderfully intense when we get sleep, or demonstrably impaired when we don't get enough. So walk me through the reasons why we should be attending so carefully to our sleep.

If we don't get enough sleep, what happens? So let me start in the body and we'll just go through maybe the major physiological systems. So firstly, reproductive health. What we know is that men who are sleeping just four to five hours a night will have a level of testosterone, which is that of someone 10 years their senior. So a lack of sleep will age a man by a decade in terms of that aspect of wellness and virility. We see equivalent impermanence in female reproductive health caused by a lack of sleep. Stepping away

from the reproductive system, we also know that a lack of sleep has a dramatic impact on your cardiovascular system. There's a great example from perhaps the largest sleep study ever done. It affects 1.6 billion people. It is sort of undertaken across about 60 different countries twice a year, and it's called daylight savings time. Now in the spring, when we lose one air of sleep, we see a subsequent 24% increase in heart attacks the following day, which stands me. In the autumn, in the fall, when we gain an air of sleep, we see a 21% reduction in heart attacks. That's how fragile and vulnerable our cardiovascular systems are. And by the way, you see exactly the same profile for road traffic accidents on our streets,

even sewer side rates, following daylight savings time. I'll speak about the immune system, though, because that's something else that's fundamentally regulated by a lack of sleep. It doesn't require a whole night of sleep deprivation. I can take an individual and we can deprive you, let's say, of four hours of sleep. So you I can take an individual and we can deprive you, let's say, of four hours of sleep, so you only get four hours that one night. And then the next day we measure

some critical anti-cancer fighting immune cells called natural killer cells. And they're almost like the secret service agents of your immune system. They're very good at identifying malignant tumors and destroying them. After one night of four hours of sleep we see a 70% drop in these natural killer cells, these critical anti-cancellating cells, and we could just sort of keep stepping through the body. But let me just take a moment to go upstairs in the brain because sleep is not just for your body, it's in fact by the brain of the brain and perhaps most importantly for the brain because sleep is not just for your body, it's in fact by the brain of the brain and perhaps most importantly for the brain. One of the most feared diseases in developed

nations is Alzheimer's disease. And what we've discovered over the past just five years now is that there's a remarkable sewage system in your brain that kicks into high gear at night while we sleep. And that sewage system is called the glimphatic system. Now you have a similar system in your body that everyone knows, it's called the lymphatic system, but we didn't realize the brain also has a cleansing system called the glimphatic system. And one of the sort of toxic metabolic byproducts that sleep using this system will wash away at night is a sticky toxic protein called beta amyloid. And beta amyloid is one of the protein culprits underlying Alzheimer's disease.

And so what we see is that even after one night you can bring perfectly healthy people into the laboratory. You can actually remove their sleep, or even just selectively remove their deep sleep, which is when that sort of system, that sort of good night sleep clean kind of power cleanse actually happens. You can just selectively remove that type of sleep. And the next day you do what's called a spinal cord puncture, and you siphon off some of the fluid. Who volunteers for this kind of study? You have to pay them rather a lot of money and be very nice to them. And they never do this study again, probably. So what we find is that that measure of cerebrospinal

fluid that we take from the spinal cord tells us what's going on in the brain. And you see an immediate next day rise in the amount of this beta amyloid toxic protein circulating in the system. And this is in healthy people after just one night. So now you can imagine what happens if you scale that across weeks or years. But it's like compounding interest on a loan every night that you're short-changing your brain of sleep. You're not cleansing the brain of that beta amyloid, that toxic Alzheimer's protein, and so it starts to scale. And it doesn't scale in a linear fashion, because it's an exponential. And that's exactly what we see with Alzheimer's disease as a pattern of pathology and as a

pattern of cognitive decline. And just last year we published evidence that those two things that as you get older, your sleep gets worse and as you get older, your memory gets worse, those two things aren't simply coincidental, they're actually causally interrelated. And so we're really understanding so. Life is short and it's full of a lot of interesting questions. What does happiness really mean? How do I get the most out of my time here on Earth? And what really is the best cereal? These are the questions I seek to resolve on my weekly podcast, Life is Short with Justin Long.

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you get your podcasts. You can also listen to ad free on the Amazon Music or Wondery app. So much more now about the fundamental role that sleep plays in every one of these physiological systems in the body and operations of the mind. We can also speak about sleep and mental health. Hopefully, at some point, that link is incredibly strong. Let's talk about that now, because it's just where I was going in my mind with this. What is the impact of sleep on our emotions, on our relationships, our ability to perform? Yeah, it's now really very clear. Firstly, if you take sleep away from an individual and you look at the changes in their brain, there is a deep emotional center of the brain that I know

that you've spoken about before called the amygdala. And it's one of the centerpiece regions for the generation of impulsive, strong reactions, particularly negative emotional reactions. We did a study where we took people and we deprived them of sleep for a night, put them in the scanner, and that part of the emotional brain showed a 60% increase in its reactivity the next day. What was worse was that... So in other words, you're freaking out more results. So yeah, your emotional brain is just incredibly sensitized by a lack of sleep. And part of the reason that we found

is that there's another part of the brain called the prefrontal cortex, and particularly the middle part of the prefrontal cortex that sits right above your nose, but two inches above that. And just to say you may be about to say this, but prefrontal cortex is involved in regulating our emotions. That's right. So you can think of your prefrontal cortex almost like the CEO of your brain. It's a set of CNN. It's a set of CNN, really.

Yeah, sort of high level top down executive control decisions. And it's normally nicely linked to that sort of Neanderthal emotional brain, and it controls it. But without sleep, that connection had actually been severed, and as a consequence, without sleep, we become all emotional gas pedal and two little regulatory control break, as it were. And what was frightening to me in some ways was that that neural signature

was not dissimilar to numerous psychiatric conditions. And we're now finding links between a lack of sleep and disorders such as anxiety, PTSD, included, schizophrenia, depression, and tragically, most recently, suicide as well. In fact, sleep disruption seems to predict suicidal thoughts, suicidal attempts, and suicide completion. And in the past 20 years of studying this field with sleep and mental health, we have not been able to discover a single psychiatric condition in which sleep is normal.

So I think sleep has a profound story to tell in our understanding, maybe our treatment perhaps our prevention of grave mental illness. Yeah, it also has a profound story to tell about who we are and how we operate as a species. Yeah. So now that you've scared the pants off of everybody, you're welcome. Hopefully you've scared their pants off and put their pajama pants on. Let's just talk about what we can do to make sure we get enough sleep. Before we dive too deeply into that, I wanna ask, I can imagine people in the audience

are thinking, okay, I'm listening to this. I'm in the midst of a lifetime of suboptimal sleep. In other words, I've got years of compounded suboptimal sleep. Am I screwed or can I get my act together now? It is the salvation. Yes. The answer is yes and no. No, in the sense that sleep is not like the bank.

You can't accumulate a debt and then hope to pay it off at a late and point in time. So you can't short sleep during the week and then try to sort of binge sleep at the weekend. It's not a credit system like that. So what has happened has happened sort of in the past, retrospectively in the rearview mirror, whatever damage was done by a lack of sleep has been done, but it's never too late to start sleeping better. And I'm not just sort of pulling out my pump- and being sort of rar-rar, we know evidence.

So, there's a study and we've done some of these studies too, where you take a group of midlife adults who have untreated sleep apnea, which is a sleep disorder with heavy snoring. Apnea simply means the absence of breath to where people are sort of sleeping at night and then they're starting to snort and then they stop breathing. If by the way you know of anyone who snores or you know as a listener that you are snoring and having that go and see your doctor, it is a deathly disease and there are treatment outcomes there. It's probably the most underdiagnosed sleep disorder. We think about 80% of people who have it don't know it.

It's the only way to know whether you should be worried about this is if your partner or anybody who's ever been new when you're sleeping says you're snoring. So that's the first indication. There are apps out there that you can sort of download that will listen to you and give you a snoring sort of measure. The other thing you can do is just go online and search for the term stop dash bang. Now, hear me out. STOP-B-A-N-G. It's a questioner and it allows you to assess your relative risk of sleep at me. And you can fill it out online and you can get a score and that will also give you a ball park estimate. But if someone is telling you that you're snoring and to the point where you could wake

them up, then you definitely need to go and see a sleep doctor and see if you can sort of explore whether you do actually suffer from clinical grade sleep out near. So we had this cohort of patients and they had, at that time, undiagnosed as sleep apnea, identified it and then gave them a treatment, which is this small face mask that keeps the airway open so they stop snoring. Of course, CPAP. CPAP machine, yeah, stands for Continuous Positive Airway Pressure, CPAP. And it turned out that about half of these patients complied to the treatment over the

course of a decade or 15 years, and the other half didn't. So it was just of an experiment of nature as it were. And what you find is that those people who complied to the treatment, staved off the onslaught of Alzheimer's disease by 10 to 15 years relative to the group that was untreated. In other words, a causal demonstration that improving your sleep here by way of a treatment intervention can actually sort of de-risk your likelihood of developing Alzheimer's disease. So it never is too late to start sleeping better.

That's good to know. All right, so let's dive into some of your tips. Now, tip, this sounds a little glib, but your recommendations for improving our sleep. One of them is keep it cold. Yeah, and you're right with tips. I think people typically don't respond to rules. They respond to reasons, I think, more than rules. So if you'll allow my scientific barrage,

I'll tell you the rule, and then I'll explain the reasons. So keep it cool is one piece of advice. Most people set their bedroom temperature or have a temperature that's too high in the sort of low 70s. Optimal seems to be about 67 degrees Fahrenheit or about 18 degrees, maybe a little bit more Celsius. Why is that?

It turns out that your brain and your body need to drop their core temperature by about one degree Celsius or about two, two and a half degrees Fahrenheit for you to fall asleep and then for you to stay asleep. And it's the reason you'll always find it easier to fall asleep in a room that's too cold than too hot. Because the room that's too cold is at least taking you in the right thermal direction for good sleep. So set your AC if you have that ability, if it's safe to do so, crack open a window if you can't regulate the temperature, if that would help depending on how cool it is outside. If you can't do that, a standing floor fan to call you is also helpful. The other way that you can hack the

cooling system is an dislike the word hack, but to have a hot bath or a shower, which sounds completely counterintuitive to what I've just said, but it turns out the reason most people sleep better after a hot bath, when they get in there, all of the blood comes to the surface of the skin, you get rosy cheeks, it's called massive vasododilation. And then you get out of the bath and what happens is that your skin, now with all of the blood at the surface, acts as an enormous radiator and you just release and evacuate a huge amount of heat from your core. And so your core body temperature actually plummets after a hot bath. That's why you are actually sleep better. And we've done those studies and we've played around with body temperature. So

keep it cool is definitely one of the recommendations. I think a second is light. We are a dark deprived society in this modern era and we need darkness at night to trigger the release of a hormone called melatonin. And melatonin actually helps tell your brain and your body when it's time to fall asleep. And if you're not getting sufficient signals of darkness, for example, if you're using screens or phones, even just overhead lighting in your house can have an impact, that light essentially stamps the brakes on melatonin. And so your brain doesn't get the signal that it's nighttime, it still thinks it's daytime. So no wonder many of us struggle with sleep at night. And one way you can sort of do that, firstly is to try and stay away from those devices,

at least an hour before going to bed. And stay away from your phone or tablet, but also the TV. Television usually is at a distance that's not far enough for those sort of light signals the photons to impact you. More impactful, however, is overhead light. And the recommendation would be in the last hour before bed, just turn off half of the lights in your house. Not only is that, you know, going to help your electricity bill, but you'd be surprised at how soporific, sort of dim light actually makes you,

it's almost as sort of like a sedating influence. The reason is because it's helping your brain realize it's night and your brain is then starting to respond by releasing melatonin and getting you ready for bed. What about people like me who like to read too far asleep? Reading is fine under dim light, but try to use a book if you're using an iPad, try to put it on the reverse mode

where the paper is black and the text is white, rather than having that sort of of strange and sort of white coming at you. They did a fascinating study back in Boston where they had people read a book for an hour before bed or read an iPad for an hour before bed. And what they found is that the iPad firstly delayed the release of that hormone that we were describing melatonin by three hours. So, if I did that this evening here in California, it would put me much closer to Hawaii time in terms of my melatonin release than it would California, it would delay it. Secondly, the amount of melatonin that was released was dropped by about 50% to 50%.

Third, they actually seem to have less rapid eye movement sleep or what we call dream sleep. And finally, when they stopped using the iPad, that impact on sleep didn't go away immediately. It had a blast radius of several days, almost like a wash out period, by telling impact for it was. So, television, as long as it's at a distance, not so bad. If you're going to read at night, try and use a paperbook. If it's not an e-reader, then try to make it as dim as possible. I do that sort of reverse with the screen and the text. The other recommendation you have, which you really, I hadn't ever really heard before, but you really hit it hard, is regularity.

That's right. So, going to bed at the same time and waking up at the same time, no matter whether it's the weekday or the weekend, a lot of people do this in what we call social jet lag, where you're going to bed somewhat early during the week because you have to wake up for work. And then at the weekend, you sleep in late,

maybe by two or three hours, but then come Sunday night, you have to drag your sort of 24 hour body clock all the way back, and Sunday night is usually miserable. That's the equivalent for your biology of flying back and forth from San Francisco to New York every weekend, a three hour time difference. It's torture on your biology

and it comes with health consequences. And our bodies are designed for regularity, including your sleep weight rhythms. If you give it regularity, it often can take care of itself. So regularity is king in that sense. It really anchors your sleep and sort of can improve the quantity and the quality of that. But you're asking people to fundamentally change their social lives perhaps. Some of it may require a change in social life and

I fall prey to this too. I'll typically try to have earlier social engagements than later, not quite the early bird special, but yeah I think it's if you want to prioritize that aspect of your sleep and you realize how important sleep is. You know, I'm not trying to tell anyone how to live their life. I can tell you about the science of sleep and then when you know that knowledge, it's up to you how you'd like to live your life. What I would say is from the evidence that we have right now, there's a very simple truth. This is epidemiological studies and

causal studies across millions of individuals, the shorter your sleep, the shorter your life, short sleep predicts all-cause mortality. So I cannot think of any more efficacious, freely available democratic and powerful health care system than this thing called a full night of sleep. I mean, it is Mother Nature's best effort yet at immortality. So what do you, I'm just curious about how you operate personally. What time do you go to bed? So I'm sort of a 10 to 10 30 to bed guy and usually I'm starting to wake up around sort of 6 30-ish. So I give myself a non-negotiable eight-hour opportunity of sleep, usually

eight-and-a-half hours. And again, that's not because I want to sort of seem like I practice what I preach or I want to be, you know, post-a-child for sleep. If you knew the evidence as I do, it's purely selfish. You know, I don't want to live a shorter life, nor do I want to live a longer life, but in sickness or disease. I want both a longer life and a longer health spend, not just a longer life spend. For example, my family has on both sides a very strong history of cardiovascular disease.

And we know that sleep is probably one of the best forms of blood pressure medication that you could ever want. And so, you know, I sleep that amount for selfish reasons. And what do you do if you've got something you want to do on a Saturday night? Do you suck it up? Or do you say no? You know, if I will always try and find a way to, you know, leave early in a vaguely graceful manner, people generally know what I do and so I get

a bit of a get out of jail free card in that sense. But I do, I do really prioritize it. Now it's not to say that I'm so pure technical that there aren't times when I'll stay out late and I'll get to bed late. I will still wake up at the same time the next morning because otherwise what starts to happen is you just drift forward in time. You go to bed late then you want sort of wake up late and then that following evening, you're not tired at the same time. So what happens, you go to bed even later, which means that you wake up even later and it's this self-fulfilling prophecy. At some point you have to pay the piper. You just have to cut yourself off that next morning. Know it's going to be a short night of sleep. Know it's going to be a

rough day the next day. And then get back into set the following evening. That happens more to me as with travel due to jet lag than it typically does inform by social life. Right, because you do travel quite a bit, I would imagine. And how do you how do you deal with that? So you can't cure jet lag. Well, there is a cure for jet lag, which is don't travel, but you can treat it. There are actually ways that you can emeliorate the effects. Lots of tips.

Firstly, as soon as you get on the plane, immediately turn all of your clock faces to the time in the new zone where you're going to travel to. And then your mental mindset, your operating system is already in that time zone. And it's important because it informs you as to when you should sleep. A lot of people sleep at the wrong time, especially on long haul flights. So let's say I'm traveling from San Francisco to back home to London. London eight hours ahead, I get on the plane at 4pm in San Francisco to back home to London. London eight hours ahead, I get on the plane at, you know, 4 p.m. in San Francisco, well, it's already 4 a.m. in the morning. So when I get on the plane, I should actually sleep

in the first half of the flight, which is when everyone else in London is asleep. When I see other people typically sleeping is in the second or the last part of the flight, which is now 10 or 11 o'clock in the morning, which is when everyone in London is awake, and no big surprise when you do that, you get off the plane, and then come that following evening, when everyone else is going to bed at 10 or 11 midnight, you're lying there in bed, having gone to bed at the same time, and you're wide awake, and you don't understand why, and the reason is because you didn't wake up until essentially 11 a.m. that morning.

But how did you get yourself to bed at 4 o'clock in the afternoon? So, you know, one way you can try and do it is starting to wake up a little bit earlier and earlier in the week beforehand, so try to bring yourself back to that time. Second, stay away from alcohol and caffeine on the flights. They are served liberally, but they are the enemies of sleep. And these are probably two other big recommendations I have for people for how to sleep better tonight. They make me deeply unpopular, but I'm generally an unpopular person based on personality, but this makes it even worse. Caffeine is, everyone knows, it's a stimulant, it's a psychoactive stimulant, and I think

it's the only one that we freely give to our children without too much concern. But most people know that it keeps you awake. What you don't know is how long it's in your system. So caffeine has a half-life of about six hours, and it has a quarter- of about six hours and it has a quarter life of 12 hours. What that means is that if you have a cup of coffee at noon, a quarter of that caffeine is still swimming around in your brain at midnight. So having a cup of coffee in the middle of the day is the equivalent of getting into bed at midnight and before you turn the light out, you swig a quarter of a cup of coffee

and you hope for a good night of sleep and it's probably not going to happen. So be mindful of caffeine intake I tried to sort of recommend people, you know, cut it off maybe 14 hours before bed, 12 to 14 hours. The other thing is alcohol. You know, a lot of people will say, I really enjoy a nightcap in the evening, it helps me sleep and I helps me fall asleep like that and I sleep, it knocks me out. Sadly, alcohol doesn't do that. Alcohol is a sedative and sedation is not sleep, but when you have a drink in the evening,

you mistake the former for the latter. You think that you're actually asleep, but you're not, you're just simply blunting your cortex. So you're not falling asleep faster. And if I were to look at the electrical signature of your sleep when you've had a drink in the evening and show it to you, it's very different than the signature of natural normal sleep. And the final two problems with alcohol is that firstly, it will fragment your sleep. So you wake up many more times throughout the night. Typically they're so short that you don't remember them, you don't commit them to memory. But then the next morning you wake up and you feel unrestored or

unrefreshed by your sleep. And if you have that feeling, you know, and you're having a nightcap, you may want to put those two and two things together. The other thing about alcohol, by the way, is that it's actually quite potent to, in terms of blocking your dream sleep, your rapid eye movement sleep as well. So, the advice that I would give to people which is politically incorrect is to go to the pub in the morning

and that way the alcohol's out your system in the evening and then there's no harm, no foul from a sleep perspective, but I'd never say that on film. I rarely drink or drink either alcohol or coffee and I would imagine the same is true for you. Yeah, so I- Unless you're going to the pub in the morning. Sans pub trips in the morning. I don't drink caffeine. I have decaffeinated coffee in the morning. I drink decaffeinated tea for the rest of the day. There was a time in my life when I was drinking caffeinated black tea. I mean, I'm British, it kind of comes with the passport.

But I was finding that, as I was getting older, especially as age progressed, the impact of caffeine was increasing and getting worse too. And that's in part because as we get older, our sleep just becomes more fragile. So anything that's trying to invade the sleep process just has an easier time of doing it as we get older. So, you know, this advice is only becomes ever more, I think, recommended as the age clock advances. And then in terms of alcohol, I've just never enjoyed the taste. So I don't really drink very much. So, I sound desperately boring.

Well, I mean, you're a good company. A bad company, I don't know. I don't know how to frame it. You think you'll typically lose the will to live in front of me when they hear what I do. So, what if we want to drink in moderation? What, do you basically have to pay the piper? Yeah, you have to understand that again, it's going to harm your sleep. People have done just studies with a single glass of wine,

as they've done with a single cup of coffee in the evening, and both of them separately will have that impact. So, I'd love to say otherwise, but that would be scientifically untruthful, and I'm just a scientist to give you the data, So, you know, I'd love to say otherwise, but that would be scientifically untruthful, and I'm just a scientist to give you the data, and then what you do with that data is entirely important. I'm not inclined to kill the messenger.

Let me just take you back onto the plane of four o'clock though, when you're flying from San Francisco to London. Yeah. How I know you were fraying from alcohol and caffeine, but I mean, the only way I'd be able to put myself down at that point would be to take a volume. So what do you do? So as I said, one of the things I'll start to try and do is just thin slice my sort of wake up time and to bed time in the week before, but you can only do that by about 30 or 40 minutes before it becomes unreasonable. The second thing I typically do is I will take melatonin with a caveat

though. So, firstly, many people will use melatonin as a sleep aid here in America. It's not regulated by the FDA, so you can buy it over the counter. Most people take too much, they either take 5 milligrams or 10 milligrams. The danger there is that it actually shuts down your body's own production of melatonin. So aim for somewhere between half a milligram to 3 milligrams is really advised. When you're stable in a new time zone and you're young and healthy, melatonin doesn't seem to necessarily help you with your sleep. The older that we get, the greater the benefit that we see with melatonin, once you are stable in a new time zone. But for everyone, no matter what age, when you're travelling and you're in a different time

zone within the first few days, that's when melatonin does seem to be efficacious. So what I'm going to try and do when I get on the plane is I will take three milligrams of melatonin, and then that tries to fool my brain into thinking, well it was 4pm and you know it's at least sort of five or six hours before the darkness signal is going to rise. And then all of a sudden it gets the signal saying, oh no I'm sorry, it actually is night time. And that will help sort of bring my sleep on set earlier and allow me a greater probability. It's not guaranteed but a greater probability of falling asleep. Meditation helps. And of course, you know, in some ways I wanted to discuss this. What's

interesting, probably about four years ago, as I was writing this book on sleep, I was not always asleep. Why we sleep? And you don't have to read the book, you just have to buy it. That's all I ask you to do. And I was not a meditator at that point. And I'm pretty hard to know a scientist and I thought some of that meditation, you've spoken elegantly about this before, that it had this stigma associated with it. It was a bit woo-woo. But there was lots of data coming out on the benefits of meditation to help you fall asleep and fall asleep faster. And so I started doing my research just so that I could write about it in the book and describe the science. And it was quite powerful and it was only getting more robust as an effect. So I thought well I'll

start maybe I'll start to try it myself because you know I'm not immune to a bad night of sleep. There are times when I can get anxious and stressed with work and it doesn't help me with my sleep. And we're still when you know everything about sleep, by the way, you become the Woody Allen neurotic of the sleep. Well, you're lying in bed at this point. I'm thinking, okay, so my prefrontal cortex is not shutting down. My brain is not releasing enough melatonin. I know that my other hormones are not,

you know, at that point you're dead in the water for the next two hours, it's a terrible affliction. So I started to meditate and I found it incredibly helpful. And that was four years ago, and you know, just as I was walking in here to do the interview, I got my notification from 10% happier, and I'm not trying to, I was saying, you know, it's time for your meditation. So you don't, because we're doing this interview in the middle of the day, San Francisco

time, so you don't meditate right before bed? I often will strategically meditate at bedtime. If I know, and I can sense it, I know when I'm stressed, I know as many people will, that you've just got that roller dex of anxiety and concern. And you know that sort of feeling in this modern day and age were constantly on reception. Very rarely do we do reflection. And for many people, the only time you do reflection, unfortunately, is when your head hits the pillow, and that's the last time that you want to start doing your mental processing.

And I think that's the reason that if you look at meditation and meditation apps, if you pull out usage statistics, what you'll see is this incredible spike right around bedtime. I've got our tech team in the room here and they're nodding their heads. And what's happening is that people are self-medicating the problems with sleep by way of medicine. It's beautiful. It's almost as though it wasn't initially designed for that, but the audience, suffering from this modern era of sleep difficulty, found when it was helpful and it's helpful

at all times of day, as we know, but one of the times that it's helpful is at night. I find it a little surprising and I'd be interested to hear you walk through a little bit of the science on this because if you translate the word Buddha, it means awake. Yeah. So I don't know that the original, I'm not intimate with, intimately familiar with the mind of the Buddha, if I was, my life would be quite different. But I don't know that the original design of the practice was for sleep. What I do notice is when I go on meditation retreats

where I'm meditating all day, every day, my sleep goes down to just a tiny nub. And I feel great. So I've always been sort of confused by the fact that meditation can help sleep given that when you're doing it at a high dose, you don't seem to need much of it. It's interesting that, and I've looked at that data actually, sort of, I've often been asked that question, there's this concept where if you're meditating and doing it intensively,

your sleep need goes down, the data actually doesn't seem to be quite in that directional supportive of it. There was a study that came out just a few years ago from Richie Davidson. The former guest on this budget. Yeah, fantastic neuroscientist. And they looked at sleep after a period of intense meditation. I think it was about eight hours during the day. I don't think that's enough.

And it's got to create that. It's got to be several days in to attend a meditation. Okay. Seven-day meditation retreat. You've got to be several days in to attend a meditation. Okay. Seven day meditation retreat. You've got to be really deep in and then what happens is that you're just waking up at two in the morning. Yeah. And you, first of all, you get incredibly vivid.

I don't want to say this as if it's true for all human beings. I'll just say in my own experience and in the experience that's been related to me by many people, I know you have very vivid dreams and you sleep very little. And it's not like you wake up and you're exhausted, you're just awake. Right. The one thing I've heard floated by my neuroscientist friend of mine, Dr. Judd Brewer, who's not a sleep expert, is that I know of, but has done quite a bit of meditation and neuroscience. Isn't that? And I don't know if he was speaking scientifically when he said this and I hope he's not mad at me if I quote him because I'm doing it via paraphrase.

Something about the fact that when you're suffering less, other than when your mental churn goes down, you may need less sleep. I don't know how that lands with you, but I'm just passing it along. I mean, I think that would be good logic if if the only thing that sleep supported was our mental health, but sleep supports as we've spoken about, all of your physiological systems, your cardiovascular health, but sleep supports, as we've spoken about, all of your physiological systems, your cardiovascular system, your immune system, your thermoregulatory system, your reproductive system. So all of those things continue to need to be tended, even if your mental health is still robust and good. So I don't think there is, you know, what we do know if you have people

do an intensive period, for example, of learning, there actually isn't increased demand for sleep. Or if people who are currently sedentary and do a lot of physical activity, it typically helps with their sleep and they sleep more. And in this sort of city, and I think it's really interesting what you describe, which is how long do you have to go with intensive meditation to actually see this change? What they found was that after an eight hour intensive period, there was actually an increase, there was a 10 minute increase in the amount of sleep,

and a 10 minute drop in the amount of time that they were awake. So if anything, there was actually a driving demand for more of that sleep. I buy that because just based on my own experience, the first day of a meditation retreat, you're trying too hard. Oh, interesting. So could just be a mental effort, demand, and therefore, a increased demand for sleep as a consequence. The other thing that happens on a meditation retreat is when you're doing intensive

meditation is you realize how sleep deprived you are and how the busyness of the world you're just run ragged, even if you're getting, you know, technically enough sleep. I don't want to, again, I'm saying you too liberally here. I'll just, I want to rephrase it in my own experience. I find the first couple of days of of retreat can be quite sleepy because I've described it as being on a plane that's hitting a foamed runway. You know, it's like, wow, I've been moving so fast and all of a sudden things are slowing down and it's all washing out.

You're just washing out. You're sleep dead. That's right. You're trying to get over this chronic debt that you've been building up. Now as I said, you can't, it's not like the bank. So if I take you this evening and I deprive you of a full night of sleep eight hours and then I give you all of the recovery sleep that you want on a second night and a third night, yes, you will sleep more than is typical.

But do you ever get back all of that eight hours that you lost? And we just let you sleep and sleep and we just measure you for days and days, you never get back that full hours. You may only get back about 50% of the sleep that you've lost, which is fascinating. We can describe why I think that that's the case. But to come back about meditation, I think it's interesting too that perhaps what also changes from what I've heard is when you want to be falling asleep and waking up. You're sort of going to bed, some people have been sort of suggesting they go to bed earlier and they're waking up earlier. And it brings us to a point which is if you look at hunt together at tribes for example, whose way of life has not changed for

thousands of years and we've studied them too, not only did they sleep, you know, the sufficient amount, somewhere around about eight and a half hours total during the 24-hour period. And they usually do that in what we call bifasic sleep, where they have about six and a half to seven hours at night, and then they have a C.S. Delight afternoon nap routinely. But what's interesting, it's not just the amount of sleep that's different between the lifestyle and modernity, as we sit right now, it's the timing of their sleep. Have you ever thought about what the term midnight actually means? I've heard you say this before and you were on a mutual friend Peter Ateez podcast and you brought this up.

Yeah, and it really hit me. Middle of the night. Yes, and for them when you look at their sleep phase, it really is quite close to the middle of their sleep cycle. But for many of us, you know, it's the time when we think about, you know, checking email one last time or really thinking, you know, I should probably stop watching Netflix at this point, or Amazon Prime, no, I'm not trying to talk at either one. Or Disney Plus. Or Disney Plus. Who have you been speaking to? You understand my preference. So I think, you I think it's fascinating when you dislocate yourself from the trappings of the modern world and you do that when you go on retreat, not that I have actually been, but I know I've heard a lot about it. I think that's when you start

to actually reunite yourself with so many of our natural homo sapient tendencies, one of which is a normal sleep cycle and a normal sleep phase. Yeah, because you start to go to sleep shortly after the sun goes down. Yeah. And they've done these studies with healthy people where they've said, you know, what time do you normally typically go to bed? What do you think is your sweet spot? And they would say, probably like 11 p.m. these are young kids.

Then they just said, okay, here's your phone, I'm taking it away, say goodbye to your family and friends. We're going off on a camping trip up in the Rockies for two weeks. No electricity, not even a car light, no nothing. And surprisingly, they started to sleep somewhere around about nine hours after they washed them out. They took away that sleep that to begin with. And they acclimated to about nine hours, which is what we think eight to nine hours is the typical human sleep need. And again, they were going to sleep when they

said 11pm is my sweet spot. They were much closer to about 8.30pm when they finally finished the end of the study. But to come back to your point though and the comment on the word Buddha and what it actually means and the surprise about sort of meditation being perhaps helpful to sleep, I actually think it's helpful for at least two reasons based on the data. The first thing that I think it's helpful for is the balance of your nervous system and we have two branches of our nervous system. One is sort of the fight or flight branch called the sympathetic nervous system. The other is the rest and digest the quiet branch of the nervous system called the parasympathetic.

What we see is that people who suffer from insomnia, they seem to be too far switched over to the fight-or-flight branch of the nervous system. That part of your nervous system needs to be shut off for you to fall asleep. And we see this very commonly now at my sleep center where it's this sort of, you know, the exhaustion economy is creating this wired and tired phenotype of people. Where people are coming in and they're saying to me, look, I am so desperately tired, I'm exhausted, but I get into bed and I'm just so wired that I can't fall asleep. And part of that reason is because this branch of the nervous system is too revved up, it's

like a car being in neutral, but your foot is all the way down to the floor and you can't shut it off and you're never going to fall asleep in that state. But what's lovely about meditation is that it seems to through breath work and also through sort of a practice on the mind, it actually helps you shift out of that fight or flight branch of the nervous system mode back into the more calm, quiescent branch of the nervous system. That's the first thing that we know is sort of mechanistically the way or one of the ways that meditation works. The second is a related system in the body, which is called the HPA axis, which is the stress

axis in the body. And the stress axis releases a stress chemical called cortisol. And cortisol normally has this beautiful daily rhythm. It starts to rise in the morning, it peaks in the middle of the day, and then it should drop down at night and fall to almost its lowest point in the middle of the night. And as it's ramping down, that decrease in the stress hormone cortisol helps us fall asleep. But if you measure that in people with insomnia, it starts to fall down in the evening, but then right around bedtime, it gets jagged up again, as if the stress system and the cortisol release is increasing. And we see that in people who are struggling with falling asleep or staying asleep.

But if you look at the studies with meditation, it's wonderful that levels of cortisol, because of that stress axis, seem to actually be ramped down. And so there is a second way that I think meditation comes in and just simply quiets the body, both from a nervous system perspective and also a stress hormonal perspective. And then I think there are benefits on the mind too, but downstairs in the body, those are the two reasons that I think we're actually seeing meditation being efficacious as a sleep aid.

And the sizes of the effects are considerable, as great as that he'd done just across the way at Stanford, where they took a group of insomniacs, and they placed them on a mindfulness meditation program for eight weeks. And they were meditating, I think it was around about, it's probably about 30 to 40 minutes a day. So it was a non-trivial amount. And after eight weeks, those people responded by about a 40 minute reduction in the amount of time it took them to fall asleep. Now to put that in context, sleeping pills at best can give you, you know, eight to ten minutes. Placebo gives you six to seven minutes. So sleeping pills really aren't much above placebo, and they are very much not recommended anymore now because of the deathly consequences and the

Castle and Genic Association with Sleeping Pills, which I'm happy to discuss. But in this study, a remarkable drop of, you know, a 40-minute savings in terms of your time to fall asleep and their sleep efficiency, you know, they weren't waking up as much and they felt better rested the following day, that's a remarkable benefit. You know, if you had a drug that was giving you that kind of benefit, it would be a blockbuster, you know.

You've talked about two things I want to put a pin in and get back to sleeping pills and also naps. But since we're on meditation, what's the move if you've gotten into bed and are struggling to fall asleep? Do you recommend getting up and going to sit somewhere to meditate or turning your phone on and meditating while you're in bed?

What do you think was your bed? It's a tough situation. I think I would offer three things that people, three sort of practices that you can try. The first is that you can try to meditate in bed, that if you are practiced enough and you can walk yourself through a meditation, you can certainly try that and stay in bed. The only danger though is we typically recommend that people don't

stay in bed awake for longer than about 15 or 20 minutes. If you haven't fallen asleep within 20 minutes or you've woken up and you haven't fallen back asleep, don't stay in bed. And the reason is because your brain is this incredibly associative device. And very quickly it will learn that your bed is the place of being awake and not being asleep. And this is why patients will sometimes say to me, look, I don't understand it. I'm watching television in the evening and I'm falling asleep on the couch and then I get into bed and I'm wide awake and I don't know why. And the reason is because you've learned the association that your bedroom is the place of being awake, not being asleep.

So the way that you break that association is by not staying in bed awake for very long. You get up, go to a different room, or different part of the room if you don't have that luxury. And in dim light, just read a book or try to meditate. And only when you're sleepy and there's no time limit, should you go back to bed. And that way you will relearn the association that your bed is the place of sleep. And I think the analogy there would be, you know, you would never sit at the dinner table waiting to get hungry. Why would you lie in bed waiting to get sleepy? And the answer is that you shouldn't. So the recommendation would be, take

your meditation practice outside of the bedroom and that way you're not associating that bad context of being awake with your bedroom itself. Outside of the bedroom were the bed, because I meditate in the bedroom, but in a chair in the corner. That's, I think that's somewhat safe as long as you're not thinking of the bedroom writ large as a trigger. That's the only time that the entirety of the context itself can be learned and imprinted. And if that's the case, then you really need to share that association and go somewhere different. But if that's not the problem, if you're not struggling, then staying in the room and just sort of practicing the, is just fine. So it seems like you're saying the bedroom should be kind of sacrosanct. I mean, my wife sometimes, she'll sometimes work on the bed.

Sounds like that's a bad idea. But idea, because then again, you're learning the association that when you get into bed, it's a place of active cognitive thought and engagement. Right. So your bed really should be like a cave, you know, it should be dark, cold and free of technology. What's your pre-bed ritual? And what are the what's what are the sort of pieces of sleep hygiene? Do you recommend? So I typically have a wind down schedule of about an hour. So an hour before bed,

that's it. I start working. Even their work is what I love and adore. And I have an obsession with. I just know that I'll still have that fizzing mind if I just work straight up to the point of sleep. You know, I may fall asleep, but I know it will come back to bite me throughout the night because of that roller dex of sort of concern and anxiety. So, an hour before bed I just could it short. I'll usually either read or just watch something light on television. That's where I sort of get my sort of fiction hit from and I think you've said this too. You know, I typically don't read fiction books anymore. I consume

sort of nonfiction. And so I use television as my fiction hit. And then I'll usually start sort of preparing for bed at that point. I've usually dimmed down all of the lights in the home. I haven't been looking at screens. I've removed about half of the light bulbs in my bathroom because that's usually the last point of contact before you go into your bedroom. You really don't want that glaring. And then I'll just sort of make sure that my room

is cold at least an hour before I'll start a fan. I have a fan inside of my room. I typically, and one of those people who gets hot at night in the thermal sense, just a bit FYI. And I have no chance of the other. So, and at that point I've cracked windows open, the bedroom is usually then nice and cold. I have a very dim light, I mean a light that you could probably almost not read by in my

bedroom, just so that I'm not cracking my shins on the bed frame as I go in. So I've already started to scale down the light infusion that I'm having. And at that point, I'm pretty sort of free of my work baggage. If I feel as though, and I can tell it, I've got that jag that I haven't processed and I haven't let go of something that's on my mind.

At that point, I know I'm just going to either stay outside of the room, or like you, I have a chair in the corner, I know I'm just going to either stay outside of the room or like you, I have a chair in the corner and there I'll just sit and I'll just usually do about a 10 minute meditation and that really helps me. And so what's the beef with sleeping pills? Sleeping pills are, no I should say I'm not anti-medication and I'm not against big farmer companies. I know the scientists there who do a lot of work on those drugs and everyone wants to help people and help disease and sickness.

Unfortunately, however, the sleeping pills that we have right now do not produce naturalistic sleep. They are a class of drugs and I'm not going to name them because they're all much of a muchness in terms of how they actually operate on the brain. They're all a class of drugs that we call a sedative hypnotics and it comes back to alcohol. Once again, sedation is not sleep. So when you take those sleeping pills, those prescription sleeping pills, I'm not going to argue that you're awake at night. You're not. But to argue that you're in naturalistic sleep is an equal fallacy. Now you could argue maybe that's not so bad if it didn't come with health consequences,

but unfortunately it does. There have been some remarkable studies out of UCSD where they've tracked thousands of people taking sleeping pills across just several years, compared them to thousands of match controls. Firstly, what we see is that you have a significant increase in your mortality risk if you're taking these sleeping pills. Every day or occasionally. So they found there was a significant increase in mortality risk, even if you were taking somewhere between three to 17 pills per year. So it was quite

striking. And then it scaled the more that you- And by sleeping pills, I know we don't want to name names, but there are pills that are specifically designed to sleep, or what about an anti-exhide, benzodiazepine? So, yeah, so these drugs, the sleeping pills, have very similar qualities to them. They all target a particular type of receptor in the brain called the GABA receptor. And I won't bore you with what it is.

But it's essentially the stop signal in the brain. And all of these drugs, the anti-anxiety drugs, included these benzoes that you speak about, they all essentially tickle the same sort of brain inhibiting receptors, just like sleeping pills. So I have to get up really early on Saturday and Sunday mornings to anchor a good morning America. And so one night a week, my doctor will let me take a benzodiazepine.

You would say flush those down the toilet. I can send you the scientific evidence, and you can make the judgment call yourself, but the evidence is not favorable. The other component of it is that they also found a relationship with cancer and it scaled with sleeping pill use as well. Now I want to also note however that those studies aren't causal, they're simply associational and I can give you a counter-argument. For example, it could be that people who are taking sleeping pills have had bad sleep all of their life, and that's why they have a shorter lifespan. That's why

we know that sleep is strongly lack of sleep is strongly related to numerous forms of cancer, so much so that recently the World Health Organization, by the way, classified any form of night-time shift workers a probable carcinogen, jobs that can induce cancer because of a disruption of your sleep weight rhythms. So we know that that evidence between a lack of sleep and cancer is strong. So maybe the reason I'm seeing this association, the literature, is just because those people who are now taking sleep and pills have had bad sleep all of their life and no wonder they're more likely to die.

It's not the pills themselves. Yes, but your argument against the pills is not limited to the carcinogenic effects. It's not. It's not. It's the fact that you're not getting, as you say, naturalistic sleep. But, of course, you're not truly asleep. You're not getting the rest you need. Yeah, and we'll probably never be able to do those causal studies in humans, because the evidence is so powerful of a link between your death risk and your cancer risk that, ethically, it may not be possible. We have some evidence in animals studies though.

One of the critical things with sleep is that it helps actually with learning and memory. So when you learn information during the day, it's at night during sleep when you essentially hit the save button on those new memories, so that you don't forget. And sleep actually helps increase the strengthening of the circuit, the memory circuit.

And one of the studies that they did in rats was looking at the effects of these sleeping medications. So they had a learning experience and then they let the rats sleep. And normally what you see with healthy normal sleep is this strengthening of the memory circuit. But then they also dose them with sleeping pills. Now the rats slept longer, so you would imagine that if sleep is good for learning in memory and it helps strengthen the memory circuit, then if they've slept more they should have an even stronger memory trace. The opposite was true. Not only did that sort of sleeping pill induce sleep not strengthen the memory, it actually unwired the memory circuit. There was actually a 50% reduction in the strength of the memory circuit.

So there's a good example that you can be thinking that they're helping you sleep, but the benefits of that non-natural sleep are not only sort of not sort of increased or amplified. If anything, they're actually taken away. It's interesting. I invoke this name before Peter Atia or mutual friend. You did a fantastic six hour three session. He is. You did a six hour three session podcast that I recommend people listen to with him on sleep. And one of the things that I heard you say is that you're pretty conservative to say the least about sleep aids, but you think if I'm getting you right, if I heard you correctly,

you think there may be, maybe some promise to CBD. So right now, I think there is, I I mean there is a, if you think about our conversation regarding meditation apps and the self-medication of sleeping difficulties with meditation, the same seems to be true with marijuana, that if you look at some of the usage, a lot of it happens at night to try and help people again medicate their difficulties with sleep. Now there's been a lot of work on the psychoactive component of marijuana which is called THC tetrahydro-canebinole. And the data there is not favorable. It may help you lose consciousness more quickly so it may fool you into thinking that you're

falling asleep faster, but THC unfortunately actually disrupts your rapid eye movement sleep, again your dream sleep, and that's not ideal. Also what you do is you build a patolerance, and so when you stop using, not only do you typically go back to the bad sleep that you are having, but you can often have what's called rebound in some near, which is that your sleep is even worse. And it's not good to build a crutch and a tolerance and a dependence on a sleep aid. However, CBD, which is the non-psychoactive component of marijuana, which is now starting to explode on the scene, the studies that look interesting, I think I would say. We don't have anywhere near enough data yet for me to be in public saying definitely

recommend CBD. But firstly, there seems to be evidence that it can help sleep and not necessarily come at a cost in the same way that THC does. We also don't seem to typically see the development of tolerance and thus a withdrawal profile when you stop, which is beneficial as well. And in the studies in animals, there again, there seems to be a benefit. And those studies in animals, and I know for some people, animals studies, and I completely understand it, you know, are difficult to feel good about.

But one of the upsides of those is that it's very difficult to sort of think about a placebo effect there, because, you know, they don't know what they're getting, and they typically have a sugar pill or, you know, an active drug, and it's difficult to sort of argue that that's a placebo effect there too. So, I think firstly there needs to be a lot more work that should happen. And I'm actually kicking around the idea of just doing this myself, you know, trying to do a Kickstarter or get some funding, you know, if anyone out there would like, you know, has a little bit of money in their pockets and they would like to try and fund this type

of study and do it scientifically. I really think it would be a good service to the field because if it's promising, even if it's got a stigma now, we need to know about it because people are desperately struggling with sleep and I'm committed to trying to help them and if this is a promising thing we need to find it out but do it scientifically. Especially since there don't seem to be many other sleep bays out there that you can recommend comfortably. Right. Exactly. And so that's, you know, if it does hold promise, we should know, if it holds dangers, we should know. I think the other big problem, though, right now, is that just as with melatonin, because it's not regulated by the FDA, even though the FDA is now starting to get much more interested in CBD and it's starting to think about legislation, it's a wild west out

there. So, you know, having a trusted brand is very difficult to come by. And there's lots of brands that are saying, you scan this QR-i code on the bottle and it will give you a lab report from the Interprint. And I think that's a good start. But even then, how can you trust it in an unregulated space? As promised though, let me ask about NAPS. You pro-NAPS are against NAPS. Four and against.

If you can NAP regularly and you're not struggling with sleep at night, the NAPS are just fine. That's the bifasic sleeping that you were ever trying to do. Yeah, exactly. And you see this in Mediterranean cultures as well, sort of the CS Delight behavior. But if you can't NAP regularly and especially if you're struggling with sleep at night, the advice is don't nap during the day.

And again, this is a rule, but let me sort of unpack the reasons behind that rule. From the moment that you and I woke up this morning, a chemical has been building up in our brain. That chemical is called a dynacine, and it's a sleepiness chemical. And the longer that we've been awake, the more of it that builds up, the more of it that builds up, the sleepier that we feel. So it's a good healthy sleepiness game. It's what we call sleep pressure. But then at night, what's wonderful is that the brain gets the chance to essentially jettison all of that

healthy sleepiness chemical. And it takes about eight hours to remove about 16 hours of accumulated adenocy. So after about eight hours of sleep, what you should do is wake up feeling refreshed without sleepiness because you've given the brain the chance to sort of remove that sleepiness. And by the way, that's probably one of my best tips for if you, how do you know that you're getting enough sleep? If you didn't set your alarm, or your alarm didn't go off, would you sleep past your normal alarm time? And if the answer is yes, you're clearly not getting enough sleep, but I digress. Well, just on that digression, and I should have asked this earlier, what is the minimum amount of sleep that we should be aiming for? Somewhere between seven to nine hours for adults over 25 years. The number of people based on the data that can survive

on less than seven hours of sleep without showing impairment rounded to a whole number and expressed as a percent of the population is zero. But coming back to a dinner scene in NAPS for a happier, jolly, a story. So what I was describing there is this kind of removal of that healthy sleepiness as we sleep, and so we wake up refreshed. But here's the danger with naps that you've been building up all of this healthy sleepiness, and then you take a nap in the afternoon, and it's like a pressure valve on a cooker. You will release some of that healthy sleepiness, and that can mean that when it comes time to

fall asleep at your normal bed time, it's a struggle because you don't have that same amount of healthy sleepiness weighing you down wanting to push you into sleep. And that's why I always recommend if you are struggling with sleep at night in general, then don't nap. You want to build up all of that healthy sleepiness, so it gives yourself the best chance to get to sleep. Does your power through even if you feel like crap, just power through? Yeah, and avoid the caffeine because what caffeine does is that it actually comes into the brain and it latches onto the receptors of a denocene and it hijacks those receptors and it essentially hits the mute button on the sleepiness signal. That's how caffeine works. It's no big surprise that they sound very similar at the end of their chemical names, caffeine adenosine. Caffeine races in and it essentially just picks up the remote inside of the brain for

sleepiness and it does hit the mute button. So now even though you've been awake for 16 hours, your brain with caffeine circulating inside of it says, oh, I'm going to second, I thought I'd been awake for 16 hours. I'm not getting that signal anymore. I feel like I've only been awake for eight hours. And that's why you get the jag of alertnessness and that's why caffeine can be damaging to sleep. Okay, so there are people out there who have struggle mightily to get to sleep. You know, insomnia is real and a lot of people deal with it

and I know you see these folks directly in your, I would imagine in your sleep center. So what is the recommendation for people of chronic insomnia? So right now, the first line recommendation is not sleeping pills, and this is not my recommendation. It was a recommendation made in 2016, a landmark recommendation by the American College of Physicians. They said that, and they reviewed hundreds of placebo controls to these, based on the weight of the evidence from sleeping pills and the nominal benefit above and beyond placebo for most people Together with the dangers that we've spoken about the first line recommended treatment for insomnia must not be sleeping pills

It must be something called cognitive behavioral therapy for insomnia or C.B.T.I And here you work with your therapist, it's a psychological intervention. And across several weeks it ends up being just as efficacious as sleeping pills in the short term. The benefit on sleep is just the same. But what's better is that when you start working with your therapist, the sleeping benefits continue for now, I think the last study showed up to a five-year benefit That was maintained Whereas with sleeping pills, it's a little bit like with THC when you stop them

You go back to not just the bad sleep that you are having but typically your sleep is even worse when you come off those sleeping pills so if you are struggling with sleep, you can go and speak with your doctor and ask about a way to try and seek out cognitive behavioral therapy for insomnia. It is typically reimbursed here in the United States under many health insurance policies, increasingly so. You can just go online, you can go to the National Sleep Foundation, and you can sort of Google around and you can learn more about CBTi cognitive behavioral therapy for insomnia, wonderfully efficacious. Stay tuned, more of our conversation is on the way after this.

Okay, so that was part one. And as I said at the beginning, that we recorded this several months ago, the part one. And then I had a bunch of other questions that I wanted to ask, Dr. Walker, and I also wanted to test my own sleep. So I got a ring. It's called the Aura Ring. Oh, you are a ring. There are other, I'm not pitching this particular product, there are

lots of sleep crackers out there, that's just the one that I happen to get. And so in this part of the episode, which we just recorded recently, we sent Matthew my data and we go over that. We also talk about the impact of irregular schedules on sleep. we talk about the impact, a new study he just did about sleep and anxiety. And we talk about a fascinating and I suspect controversial idea of a sleep divorce, where couples sleep in different rooms. And I think you'll be surprised to hear where he comes down on that. So here we go with part two of Dr. Matthew Walker.

Thank you for doing round two. apparently we didn't scare you off. It's a true pleasure and delight to be chatting with you again. I think it's the opposite. I was surprised that you even wanted to speak again. I think some people have described both my voice and personality as one of the best prophylactic snowman so it's a delight to be back with you. So I have to take every invitation I can get. Not true at all. In fact, I have a mill, I walked out of our last meeting with a million more

questions, so I've written them all down. So brace yourself. I'm going to ask you with a lot of questions. Question starts at 10 fingers on buzzers. I'm ready. Okay. All right. So let's start with I wore this sleep ring for a while because I was too much of a chicken to go get a sleep study because I really didn't want to do that. But we should talk about sleep studies in a second, but you've had a chance to look at my data from my sleep for a couple of weeks. So I'd just be interested to hear your response. I think it's really interesting because sleep is one of those things firstly that we are

largely not aware of because we're typically not conscious, not at least in the waking sense of it. And so it's one of those areas of the sort of the wearable or the quantified self movement that I think is quite informative. There is a side of it that can be problematic where people get overly anxious because they start ruminating about their data and they can start catastrophizing. But for the most part, I think it's largely a good thing. And your data was actually quite interesting.

There are, I think, a number of important features that the public actually can benefit from. The first is that your sleep opportunity, meaning the amount of time that you are consistently in bed, is fantastic. You typically have about eight, even a little bit more eight hour sleep opportunity. And that's great because we know from the National Sleep Foundation recommendation is for most adults, seven to nine hours. So let's be conservative and say you're trying to get seven hours of sleep in total. But one of the things that people can flate is, time in bed is time of sleep and that's not true.

And in fact, that's what your data was suggesting too. When you are healthy, if you have good sleep, you typically have what we call a sleep efficiency score. And that sleep efficiency, if your healthy is about 85%. What does all of this mean? There are three things, sleep opportunity, sleep time, sleep efficiency. Sleep opportunity is the amount of time that you're in bed and as we said you have a sleep opportunity routinely about eight hours, which is which is wonderful. Then if you have a sleep efficiency of 85%,

which is healthy and you're in bed for eight and a quarter hours, then you will get your minimum of seven hours of sleep. And I think that's one of the problems people will say, you know, I go to bed at 11 p.m. and I wake up at 6 a. work. That means that I got seven hours of sleep. It's not true you had seven hours of time in bed, but even if you have a healthy sleep efficiency, probably means that you only got about six and a quarter hours of sleep. And we saw that with your data that you were getting about eight hours of time in bed, but because of your sleep efficiency, which was perhaps a little bit lower than we would expect. It was sort of around about 80%. And again, this is just based on a device that I think is a good device, but it's not quite

the accuracy that we would have in a sleep lab. But let's take it for truth. Your sleep efficiency was a little bit lower. So on average, your total amount of sleep that you were getting was a little bit less than seven hours of sleep a night. So I think we can start to think about ways of trying to perhaps improve the efficiency of your sleep. Your time in bed is great, but we just need to increase the amount of time that you're asleep whilst you're in bed. So what would you say I could do because I've definitely been tracking the data myself. I look at it every morning and I've noticed too that I'm in bed for eight to nine hours and often I'm very rarely cracking

the seven hour mark of actual sleep. I think there are probably a number of things that we could think about. Some are just physical, some are mental. So typically the things physically that keep us awake more during the night, especially as we get older, unfortunately, are bathroom breaks getting up to go to the bathroom. And then the second is physical pain. They're the two things that typically people struggle with from bodily perspective. And we could think about those for you. The second component, of course, is mental, and you know so much about this, which is, and those two are not sort of independent, by the way.

Often you get up, you go to the bathroom, you come back, and now the mind just sort of unleashes this rolladex of anxiety, and you start thinking, okay, well, what didn't I do today? What should I have done? What do I need to do more of tomorrow or less? And at that point, then it shifts from being a physical fracturing of your sleep onto now a mental impairment of your sleep because of that catastrophizing, because of that rumination. That's where things I think like meditation are so powerful, just to try and take the mind off itself as it were and see if you can just try to relax back the body, bring down that fight or flight branch of the nervous

system which gradually creeps up the more that we sort of go through that anxiety process. And when that branch of the nervous system is active it's very difficult to get back to sleep but things like meditation will actually quiet that branch of the nervous system down, and that's when it's easier to start to fall back asleep at night. So I don't know if any of those two pillars, the sort of the physical components or the mental components, play into the time that you're awake during the night, either of those two feel relevant? Yes. So for me, I just jotted down. There are three things that I think are getting in the way of sleep efficiency.

One is exactly what you said about having to go to the bathroom. I'm nearly 50 and apparently I have the bladder of a, you know, like a kitten. So I'm, I go to the bathroom. I get up and I have to go to the bathroom. So that's annoying. I don't know what I can do about that.

The other is noise. I have to go to the bathroom. I have to go to the bathroom. So that's annoying. I don't know what I can do about that. The other is noise. So we have a five year old, and he gets up a lot in the middle of the night. He won't accept me, which is bad for my ego, but sometimes good for my sleep. But he's, we hear him on the baby monitor

and my wife has to get up and go often sleep with him or comfort him. But I wake up when that happens. And then the third thing is restlessness. This is usually as I'm trying to fall asleep, but I often, I always meditate before I go to bed and then, and maybe often, I always meditate before I go to bed and then and maybe often stretch too. But even after doing both of those things, I find that there's can be from 60 to 90 minutes of tossing around. And yeah, so those are the three things.

And I think for, you know, the bathroom breaks, it's just, it's very difficult. That's just one of the things that we all know as we start to get older, increases in frequency. How to deal with that? There are some medications that people can prescribe to try and help, but the other thing is to try and think about what is my fluid intake in the evening. And often the trick is not to actually decrease the number of cups or glasses of fluid that you're taking in. Full your brain into thinking, I'm still having the same number of those glasses of X or Y, but just try to half the amount of the fluid volume that you pour into those in the evening. And in that way you sort of psychologically still think, no harm, no foul, nothing has changed, but decreasing the amount of that fluid can sometimes also help as well.

But medications are there too, should people want to explore that? Yeah, I'm pretty militant about not drinking any fluids after six or seven. So, maybe it's something where I want to explore with medication, but yeah, it's not awesome. And the restlessness, yeah, that's difficult too. You know, I think there are certainly stretching is something that helps, but is it a restlessness of the body or is it associated with the restlessness of the mind? The mind is quiet, it's just the body. That's restless. Yes. And do you, are you physically active during the day? Do you typically work out during the day? Yeah, well,

I'm a borderline narcissist who has to look at his own face on television all the time. So, yes, I am quite active in the gym. It's not pretty, but I insistent six to seven days a week of workouts. Okay. Usually early in the day, because I knowent six to seven days a week of workouts. Okay. Usually, early in the day, because I know that working out later in the day can disrupt the sleep, but I am pretty active. Okay. Yeah.

I think, you know, trying to think about the body probably going into a repur as it moves into that sleep phase, maybe associated with some of that restlessness, and then just doing more of the stretching and rolling out as well, the muscles can also help in that regard. Like a foam roller. That's right. Yeah. Because some of that restlessness may just be the muscles in that state.

One thing that I've found helps, and I... I wonder if this might cut against your advice, but what I've found that helps with wrestlers' sister, two techniques I've used. One is just get back out of bed and meditate again, although sometimes on two wrestlers, Steven sits still. But the other is to read. And I've found that reading, especially some boring Buddhist book that is both boring and puts me in touch with fundamental truths that have a way of relaxing the mind can knock me out. It can take a while, but that can work.

I think the latter is almost a distraction. It's moving the focus of your attention from perception of the body to actually internally thinking within the mind. When you shift that, it's almost like a spotlight focus from the body to the mind. And when you shift that's almost like a sort of a spotlight focus from the body to the mind, then all of a sudden, you know, the entire organism is ready for sleep. I think that's definitely one of those things that can help. The other thing we talked about was noise. Obviously, I'm not going to give my kid up for adoption, so that's not an option. And obviously, I'm not going to give my kid up for adoption. So that's not an option.

So I'll have to live with that for a little while. But my wife and I do wake each other up quite a bit because when I go to the bathroom, she's a light sleeper. She often wakes up and sometimes she comes to bed later than I do. And that process will wake me up. And so you've, before we started rolling, you told me about something called a sleep divorce. Can you say more about that?

Yeah, so it's something that is now becoming a little bit more common as people openly speak about this, which is having a sleep divorce to potentially prevent you from having a real one. And we know that from survey data, anonymous survey data, that up to 30% of people in couples in partnerships will report sleeping in separate rooms. And of those remaining, let's say, 70%, there's a non-trivial proportion of them who will go to bed in the same location, but will wake up in different locations. And I think this tells us that there is some kind of attention here going on

in the public regarding partner disruption of sleep. And in fact, it's something that myself and my partner, she, she's a very light sleeper and she typically has a longer sleep need. She seems to have a sleep need of around about nine hours. A night, my sleep need is about eight hours a night. sleep needed around about nine hours, a night my sleep need is about eight hours a night. So we're often offset in terms of going to bed and also waking up, which would always cause problems from sort of me getting into bed after she's asleep and she wakes up and getting up early. So we agreed to go through a sleep divorce. And I think one of the problems with having, and I should, you know, there should

be a better term for it because it's a very negative connotation in that sense for a very beneficial, potentially good upside. But the stigma is that if people say, well, goodness, you know, if you're not sort of sleeping together, then you're typically not sleeping together in that regard. But often the opposite is true that when a couple starts to get good sleep, what we see is things like reproductive hormones actually improve your physical vigor and vitality improves the emotional connections and the emotional stability of your relationship improves all of which typically leads to actually improvements in the intimacy and the physicality of a relationship.

So I think that's one aspect. It's not a one size fits all. I think some people find great comfort in having a partner with them at night and there's a huge benefit there. So I think it's find which of those two buckets that you may fit in and explore it. I think if you are going to go through the sleep divorce, is it worth? You have to think a little bit more about what it actually means in terms of that intimacy link. What most people miss about getting in to bed together is just that moment where you're saying goodnight or you're having a cuddle.

And then in the morning waking up and saying good morning to each other. But what's interesting is that for everything in between those two buck ends, you're mostly non-conscious and not aware unless you've got sleep disruption going on. So you can sort of hack the system as it were. If you do have a sleep divorce, just try to find a system where you, you know, whoever gets into bed first, the other person will come in and say goodnight to them, so you have you do have a sleep divorce, just try to find a system where you, you know, whoever gets into bed first, the other person will come in and say, good night to them. So you have that routine. And then whoever wakes up first, you can go into the kitchen, make your

decaffeinated tea or coffee. And then the other person can text you and say, I've just woken up, come and say, good morning to me. And you can still get the benefit of those two beautiful moments, but also have the benefit of getting full undisturbed sleep in between. I love this concept, and I'm grateful to you for bringing it up, and for having the courage to talk about your own personal situation. I think there's real value in you not presenting yourself as the, you know, perfect, you know, avatar of sleep hygiene. And I, it's funny because I've been thinking about this a lot and feeling sheepish. The idea of sleeping in a different room for my wife feels like down in Abby or, you know,

the crown where you see these stodgy British couples that sleep in different rooms. Although at least in town, Naby, they seem to have a healthy relationship. And I worried about that. So, you know, I, for example, some nights, when I'm restless and I wanna read so I can fall asleep and my wife doesn't like the light, some nights I will go sleep on,

go fall asleep on the couch and then it'll, it's not uncommon for that to last all the way into the morning and then my son and my wife wake me up and I go back into the bedroom and sleep for another 45 minutes. And I've worried what message is this sending my son? Is he going to think that we're, you know, mommy and daddy don't love each other? We do. We have a great relationship, but I just need to sleep and I don't want to mess up her sleep.

And so I think it's quite freeing for me at least personally for you to talk about this thing as a potentially healthy move. Yeah, I think people should feel that liberation. And it's so deep sleep is such a stigmatized topic in and of itself. It has an image problem and we associate it with people being slothful and lazy and then take a step down, speaking about a couple and intimacy, that's perhaps even more of a violation of the norm.

But I think people have to understand that sleep is just such a biological necessity. And when the two of you are getting good quality sleep, you'll just have a seemingly better quality relationship on all aspects of those things. So I think there is, you know, a discussion to be had, and as I said, it's not necessarily for everyone, but the more that we're open about this and the more that we speak about this, I think the more people will actually start to come with their own

stories. You know, when I've mentioned this before, before, to a public talk or a public speaking event, it will always be those people who wait till the very last moment, till the last question, and then they sort of sidle up and they whisper to you, you know, I'm actually one of those people. And we actually do so. You know, as if it is just this terrible embarrassment and it shouldn't be, because it's just simply people trying to obtain a biological necessity. Yes, amen. So back to my data. So we were, I can't remember what the numbers were, but it's something like a sleep opportunity

of north of eight and a actual sleep time of around six and a half with all the caveats that apply to the reliability of data that comes from a ring rather than a sleep study. If I lived the rest of my life with those numbers unchanged, would I be in at real risk for all of the health problems that you've enumerated that are associated with insufficient sleep? I think what we know from epidemiological studies which are not, you can't infer causality from those, these are simply associational studies, but what we know is that usually relative to groups who are getting sort of seven to eight hours of sleep a night, risks for things such as

cardiovascular disease, diabetes, aspects of mental health as well, together with cancer and Alzheimer's disease, those things typically start to increase once you start to go lower than those amounts. And so I think trying to think about ways to improve that sleep efficiency, I think it wouldn't, and this sounds counter-intuitive, I wouldn't start necessarily suggesting increasing the amount of time that you spend in bed, because you would think, well, okay, if I need to get more sleep, all I should do is just spend more time in bed.

I think that that's probably the wrong suggestion because you mentioned it before. One of the things that we're very mindful of in sleep medicine is not being in bed awake for too long. And your point about saying, if my body is restless, I typically will just get up and go somewhere else. That is a great piece of advice and the reason is because your brain is such an incredibly associative device. It will start to learn the association that your bed is this place of being awake

rather than being asleep. And so breaking that association, as you suggested that you do, is a very good piece of advice. And that way you will actually start to relearn that your bed is the place of being asleep. And I think the analogy there would be that you would, you know, you'd never sit at the dinner table waiting to get hungry. So why would you lie in bed waiting to get sleeping? And the answer is that you shouldn't. So I think constantly practicing that and enforcing this improvement in your association with the bed, being the place of sleep, may also help. Paradoxically, we could almost take it to the opposite end because there is a practice in cognitive behavioral therapy for insomnia, and I'm not suggesting that you actually Paradoxically, we could almost take it to the opposite end because there is a practice

in cognitive behavioral therapy for insomnia, and I'm not suggesting that you actually have insomnia. I don't think you do, which is actually you start to constrain the time in bed to enforce better efficiency. So for example, let's say that looking at your data, your embed for eight hours, and you will typically spend about an hour and a half of that eight hours a week. But then I were to give you only two hours of sleep tonight and then keep you awake throughout the following day.

And then I put you back into bed that following evening. What we would typically see is that you will actually spend a lot less time awake that following night because you have this sleep rebound where you try to recover from that sleep debt and you don't repay it all, but you'll try. And so we do a sort of a more subtle version of this where we can actually say, let's have you spend perhaps only seven and a half hours of time in bed. And gradually your brain will learn, my goodness, I used to have this luxury of an eight hour in bed sleep opportunity time. And, you know, I was driving at about

80% sleep efficiency. Well, if it's constrained, I now need to actually sleep in a much more efficient way to get what I need. And you can actually improve your sleep efficiency and in fact improve your sleep duration by constraining your sleep opportunity a little bit. I'm not suggesting that that's the case for everyone. Most people are in the opposite bucket where they give themselves too little sleep opportunity. But that's another way that we can try to play with improving sleep efficiency. It sounds paradoxical, but spending less time in bed for those people who are spending

at least seven hours or more time in bed can actually mean more time asleep. So I'm hearing three things that you think potentially I could work on given my data such as it is one is trying a medication to that would reduce the trips to the bathroom. The other is along with stretching using a foam roller and the third is and this would be the most sort of aggressive which would be perhaps examining a restriction around sleep opportunity. That's right. Yeah. And I think all of this, you know, it's very difficult to do, you know, firstly a diagnostic from so many miles away. And also one would want to sort of make sure that we got you in the sleep laboratory so we could actually see, you know, are there any other sleep disorders that were perhaps missing that could be constraining your sleep efficiency? You know, we've already

spoken a little bit offline about snoring and I don't think that that's an issue for you, although it is an issue for many people. Things are just restless legs syndrome as well. Those are the things where people just get these stretchy legs and sort of just an itchy need to move them around and that can disrupt sleep quality. So, but I think you're right. I think those things trying to implement those things. The other aspect of sleep efficiency is alcohol and caffeine, and I know that we've spoken a little bit about this, but for the most part, tell me a little bit about those two things and how they

play out throughout the day and the evening for you. Neither. I don't either of them. You know, so that's one of the other things that can certainly constrain people's sleep efficiency. They can be spending a lot of time in bed, but that's fantastic. In that case, no problem to think about those there. Yeah, I appreciate you were saying that you're on the West Coast. I'm on the East Coast. You've looked at a little bit of data, but I'm not in front of you. And I haven't done a sleep study, so you can't do a total diagnostic, and I wasn't expecting that.

But let's talk about the value of a sleep study. I really didn't want to do it because I had these phantasmagoric projections of spending all night with all this stuff. All these wired, and I'm gonna have to get up and pee a million times. I'm not gonna get any sleep the next day. He's gonna suck. And I'm going to have to get up and pee a million times. I'm not going to get any sleep the next day is going to suck. Am I wrong about that? And what's the, what's the real, can you, can you really, how much can you really measure if I can't imagine I'm actually going to get that much sleep in one of these sleep studies?

So typically those sleep studies will help clinicians understand what potential sleep disorders that you have and we've already mentioned really the sort of the heavy hitting three. The first is snoring or what we call sleep, severe sleep, sleep apnea. The second restless leg syndrome, the third is just sort of insomnia really having difficulty falling asleep or difficulty staying asleep or waking up the next day in feeling unrefreshed and unrestored by your sleep. So often a sleep or waking up the next day and feeling unrefreshed and unrestored by your sleep. So, often a sleep laboratory test, as you mentioned, is not going to give you the perfect snapshot of what that person's sleep is like at home. It's more of a diagnostic tool to say, okay, come on in and let's see if there's anything glaring in terms of a sleep disorder that we can see.

And the sleep disorder will typically still be expressed in a sleep disorder that we can see, and the sleep disorder will typically still be expressed in a sleep clinic, even under conditions of a bad night of sleep. So that's really where those sleep clinics that are usually probably beneficial for people. And by the way, I mentioned those three sleep disorders, but there are many tens of different sleep disorders that we now recognize. So they are just the three probably largest, but there are many others. So what is your, you talked a little bit about this, but I'd love to hear you say more on wearables. I, I wore this ring called an aura ring. Oh, you are a ring. Yeah, I have one. You have one too. Yeah, I have one. Are you with the company? I have no affiliation with the company.

I have no connection with them. What do you think about wearables? Is this the one you would recommend? Or are there others you would recommend? How much stock should we put in the data that we get from wearables? Et cetera, et cetera. Yeah, it is interesting.

I think about wearables in two sort of different verticals. The first is about obviously accuracy. And right now, for the majority of wearables that you place on your wrist or on your finger or you strapped to your bed, they all typically try to do the same thing where they're measuring your respiration and your heart rate and using algorithms, they can try to stage the different types of sleep. Are you awake? Are you asleep? And if you're in sleep, are you in light non-rem sleep, deep non-rem sleep, or in rapid eye movement sleep or dream sleep?

And for the most part, right now, they're all much of a muchness out there. They probably have about a, you know, 70%-ish accuracy if you look at some of the data. So I think that's one way of thinking about them, and that's why, you know, I'm a little bit reticent to fully embrace the data that we have from you and saying, you know, that is exactly what I would find in my sleep abroad tree. I think it's a good proxy, and I think the ring does a pretty good job of that, but is it 100% faithful?

It's not there yet, no. So I think that's one way of thinking about it. What is the accuracy of these devices? The other way I think about it, though, is from a more pragmatic perspective. I think one of the difficulties with wristwatches or even headbands is that when we go to sleep we typically take things off, we don't put things on. And as a consequence, if you're going to be worse something that tracks your sleep,

it's really only going to be meaningful if you're constantly doing it, you know, multiple nights a week and for many months if not years. But with some devices, if you're constantly doing it, you know, multiple nights a week and for many months, if not years. But with some devices, if you don't feel very comfortable with them, if you have to put them on your head or around your wrist, then the stickiness of them, the adherence to those devices decreases quite significantly. And as a consequence, I think that can be a challenge for people. The reason I like the ring as a form factor is that people are not uncommonly going to bed wearing rings. And in that regard, I think it's less intrusive. So I think that as a result is perhaps a better form factor for tracking sleep than some

of these other devices. But there are the two different ways that I think about wearables in sleep technology right now. Yeah. I mean, I don't have any problem wearing the ring at night. I did get tired of wearing it during the day, so I just only wear it at night, which limits the amount of data I can gather on the picture it can get of your overall activity levels and et cetera, et cetera, but I just don't feel like wearing it during the day. What about, I'm sorry, did you have something you wanted to say? No, no, no, I think that that's a perfectly good policy because I think for the most

part, and I don't want to speak for the company, but I think that one of the prime focus areas right now is sleep. And so I think that if you're going to wear it at some point, the night and sleep is the place to do it. What about people who, I mean, these are expensive. So if I don't have the resources to get a tracking device, what would you recommend? At that point, maybe just get a prescription for a sleep study? Um, yeah, certainly these devices, not of the commercial devices right now are claiming

to be diagnostic from any clinical perspective. So I think if you feel as though you're worried that you have a sleep disorder, that's absolutely the thing to do. Go see your doctor, see if you can get a sleep test. If snoring or sleep apnea is the potential concern, you may actually not have to go into a sleep laboratory. Now they have these at-home diagnostic tests where they send you a box out and you sort of, you've got instructions and you can strap on a chest band and put something on your finger and put something up, you know, and you can do it at home. So there are lots of more convenient ways that continue to emerge if you want those types of sleep diagnostics, some of which are happening now at home. There are a couple things that you mentioned in this second interview that I want to

follow up on that don't necessarily flow out of that last question, but I just want to make sure I get to them. One is the idea that a problem for folks is not waking up refreshed. And I will say even when I get a quote-unquote good night's sleep, or even if I'm close to, or even north of seven hours of sleep, it's not uncommon for me to wake up and still feel pretty groggy. It's not necessarily that I feel awful, but I, it's not like I'm leaping out of bed.

How big a problem is that? Not leaping out of bed. How big a problem is that? Not leaping out of bed, that's a huge problem. I like to see people leaping constantly. If you're not leaping, come see me. No, there are two aspects I think to clarify here. The first is feeling refreshed throughout the day. So I think if you feel as though you're constantly needing caffeine to sort of keep you away. I know this is not the situation for you, but when we speak about feeling refreshed

and restored by your sleep, we're really talking about the entirety of the day, not that sort of Goldilocks time in the first hour or hour and a half after you wake up. It's very natural for people to have that gruggingness in the morning. It has a name, it's called Sleep Inertia. And we know some of the neurobiology. I actually am someone like you, I suffer from quite severe sleep inertia.

So, you know, my partner, she will sort of know that basically in the first hour in the morning, don't talk to me too much. I'm not the best version of myself. I'm just pretty gruggy and a little bit grumpy. And that's just sleep inertia. And part of the reason is that when we're asleep, different parts of the brain start to switch off, almost as though they get this recycle and this chance to rest and reboot. And one of the parts of the brain that gets taken offline is a

part of the brain that we call the prefrontal cortex that you've spoken a lot about on the podcast and in your writing. And that part of the brain is the last part that really starts to sort of come back online after we wake up. So think of your brain almost like an engine in a classic car that you can't just kind of for some people, you know, turn the key and then just floor it and drive it hard. You actually need the engine to warm up a little bit. You need to get it up to operating temperature and then it's good to go for the rest of the day. So if that experience resonates with people listening and resonates with you Dan, then I would say there's perhaps nothing too much to be concerned about regarding restorative sleep or the opposite which is unrestaurative sleep. The problem is more about saying,

well I just don't feel refreshed or restored or fully awake for most of the day. If that's the case, that's more of a problem. I think you're, let's say that you're getting your solid seven hours of sleep an night by way of having at least an eight, eight and a half hour sleep opportunity. Why would it be then that even if you're getting seven hours of sleep, you still feel unrefreshed throughout the day. Another possibility there is a mismatch between when your body wishes to sleep and when you are giving it the chance to sleep. This comes onto a topic that we call your Croner type. Are you a morning type or are you an evening type or are you somewhere in between? Often what you'll find is that evening types people who

would like to go to bed, you know, if I were to say to you, if you on a desert island, you have no commitments, nothing to wake up for. What time would you typically like to, I think, drift to go to bed and what time would you like to wake up in the morning? That's your typical natural biological chronotype. And it turns out that it's largely genetically determined, or there is a significant part of it that's genetically determined. You don't really have control over being a morning type or an evening type, it's not really a choice, it's gifted to you by your genetics. And this comes back to the idea that you may be positioning your

sleep opportunity window at a time that's not really aligned with your biological preference for when you would like to sleep. So if you are an evening type who likes to go to bed at midnight and wake up at 8am, but you're going to bed at 10pm and waking up at 6am, well they're the same in terms of total sleep opportunity time, but the quality of sleep that you will get as a night owl trying to sleep on an early schedule won't be as good as the quality of sleep that you would be getting if you were going to bed when you wanted to and waking up when you wanted to, and that will lead to a feeling of being unrestored

during the day. So that's a very long description, but sleep inertia, perfectly normal. We understand the biology, but if you're feeling unrefreshed throughout the day, you may want to think about asking yourself, well, what type am I? Am I morning type, evening type? And am I in synchrony with my biology

or am I sort of misaligned with my preferential biology? Got it. And thank you for using the term schedule, I appreciate that. It's scheduled. Sorry. The other thing I wanted to loop back to that you mentioned earlier was the link between lack of sleep and anxiety. And I know your team just put out a study on this. So I wanted to give you an opportunity to talk about that a little bit. Thank you. Yeah. So there is certainly an emerging literature now on the relationship between sleep and anxiety. For a while, it's really been in one direction.

We certainly know that people who are anxious, who are just innately anxious, who have what we call high-trade anxiety, typically don't sleep as well at night. And I guess that's no big surprise. If you're wired, if you're nervous, if you're anxious, you're not usually going to be consistently having a good night of sleep. But we actually wanted to ask the opposite direction, what if we were to disrupt someone's sleep at night, can we actually see if that causally increases their anxiety the following day?

That's exactly what we found that if you restrict someone's sleep or you deprive them of sleep, you get an immediate increase in the amount of anxiety that they're experiencing. For some of those people, somewhere between 20% to 30% of those people, after just one night of no sleep, they had actually transitioned to a level of anxiety that would be classed as a clinical disorder, so it was a non-trivial increase in their anxiety. Second we found perhaps what the underlying biological cause of that anxiety was. When you're not getting sufficient sleep, that prefrontal cortex that we spoke about

before, which is almost sort of like the CEO of the brain, it's a high level controller of our deep emotional brain centers, that part of the brain when we're not well-slapped actually is impaired. And as a consequence, those deep anxiety triggering emotional centers of the brain actually erupt in their activity, triggering the anxiety. In other words, if you're not getting your sleep at night, the brain isn't well positioned to control those emotional anxiety triggers the following day, and so you get this anxiogenic, this escalation of anxiety during the day.

What we also found, however, is that when you record people sleep at night and you give them the opportunity to get the sleep that they need, what is it about that sleep that actually provides an anxiolytic, a calming influence on our anxiety? And what we found is that it's actually the deep quality of sleep, what we call deep non-rapid eye movement sleep or deep non-rem sleep. The greater the amount of your deep sleep at night, the greater the next day reduction in your anxiety. So sleep and particularly deep sleep offers this sort of almost palliative soothing balm

on the brain and it just tapes the sharp edges off those sort of anxiety triggering events. And so it's perhaps not time that heals all wounds, but it's time during deep sleep that provides the type of emotional convalescence. And so interesting, an anxiety, a huge problem in our culture right now, so this is useful data. a huge problem in our culture right now, so this is useful data. We're in the middle on this podcast of a big January series about healthy habits. And one of the questions that my colleague Samuel urged me to ask you is, what is the impact Samuel John's one of the producers of the show, with whom you've been in contact. Fantastic, yeah. He is fantastic.

One of the questions he asked me to ask you was, what is the impact of sleep on all of the other habits that we, many of us, are hoping to improve such as exercise, diet, meditation? So there's some really good data on both diet and exercise regarding sleep. What we know is that when you start to under-sleep, when you start to get sort of 6, 5, 4 hours of sleep a night, firstly your appetite will start to increase. And the reason is that there are two hormones that control our hunger. One is called leptin and one is called ghrelin. And despite sounding like hobbits, they are actually real hormones. Leptin is the hormone that is released and when it's released it says,

you're full, you don't want to eat any more, you're satisfied with your food. ghrelin does the opposite. ghrelin is the hunger hormone. It says, you're not satisfied with your food. You want to eat more. Continue to eat. And when we deliberately deprive people of sleep or short sleep them, let's say for a week and put them on four or five hours of sleep for a week, we see increases in the hormone that says, you're hungry, you want to eat more and that's growling. But a lack of sleep will impair the other hormone that says, no, you're full, stop eating, don't need to eat anymore, which is laptain. So they go in these deleterious opposite directions.

It unleashes your appetite and you start to eat more. The second problem is that it's not just that you start to eat more, you also have a change in your preference for what you want to overeat when you're under-slapped. And specifically, you lean towards increasing your consumption of simple carbohydrates, sugary foods, things like ice cream, candy, and also you increase your intake of heavy hitting stodgy carbohydrates, bread, pasta, pizza, those types of things as well. So there's some really good evidence that when you don't get the sleep that you need, you can actually start to increase your appetite, you can start to sort of move towards what we call an obesity genic profile. But the good news is that if you're getting the sleep that you need, then you can actually eat a certain amount and feel satisfied with that food.

And so it can actually be a solution towards prevention of obesity, or at least it can be a weight gain sort of preventor. We also know that people, for example, who are dieting, but they're not getting sufficient sleep. Almost 70% of the weight that they lose will actually come from lean muscle mass rather than fat. And what we've found is that when people are under-slapped, the body becomes particularly stingy in giving up its fat. It's much more likely to give over things like muscle and hold on to fat, which is exactly the opposite

of what most people want to do when they're dieting as well. So when it comes to diet, certainly we know that getting the sleep that you need is going to promote you towards healthy sort of body mass index and healthy sort healthy dietary profile. Exercise is another great one. We know that when people are getting better sleep, firstly, their motivation to even exercise increases. That's probably one of the biggest factors that simply your desire to actually get on the treadmill or go out for a run or go out for to the gym

you can go on a hike that increases secondly when you do exercise the intensity of your exercise is typically higher when you've been getting good sleep and there's lots of components of that that people have looked at your sort of your muscle contraction, your applied force, even things such as how good your lungs are at expiring carbon dioxide and bringing in oxygen. Those things are benefited when you're getting sufficient sleep. In fact, even your body's ability to perspire when you're exercising, which turns out to be a critical thing, cooling your body, improve your ability to work out more intensely. Perspiration is impacted by insufficient sleep.

On all of those factors, we know that a good night of sleep is going to make you more likely to exercise, and when you do, you're going to do it in a more intense, more efficient fashion. Yeah, I'm not the brag, but I'm looking at my data right now. I got six hours and 47 minutes to sleep last night, and this morning I actually hit a personal record on Peloton, so. Wow.

So let me ask some questions from the perspective of a parent. I'm interested in both sides of this. One is, do you have an of you on how we can get our kids to sleep through the night? And second, what do you, what's your advice to parents who are sleep deprived? So on the latter on sleep deprived parents, it's such a difficult issue. I think there are, you know, the reason that it remains a problem in our society is that we don't typically have good solutions.

I think if you're lucky to have a partner, then trying to think about, for example, going back to Chrono type, who could take the early shift and who could take the late shift, you know, I think firstly understanding what your biological tendencies are. If you have that luxury independent of work, which sometimes is not the case, but But you know, if you're someone who says, like, I can sort of stay up pretty late, I can take that night shift if it happens from here to here. And then you're someone who typically will sleep deep in the first half of the night, unlike me, where I would like to be sleeping late into the morning. If you take the second shift, we can try to pattern match that sort of coverage as it were based on our biological

tendencies. That's one way of doing it. The second, particularly for new parents, try to get the sleep that you need whenever you can. So even if that involves daytime naps, and we can speak a little bit about naps because they do have a double-edged sword, but under those conditions where you are chronically sleep restricted, just trying to get your sleep whenever you can, it can also be beneficial too. So I think it's a very difficult problem to solve, however. For children, perhaps a little bit easier, there was a great study that was published probably about a year or two ago, and they were looking at the factors that for young kids seem to promote better sleep. The first was regularity, so trying to put

your kids to bed at the same time and having them wake at the same time, and they typically naturally will wake at the same time, but going to bed at the same time regularity was absolutely critical as it is for adults by the way too, but that was one of the key factors. Another one of the interesting factors was trying to remove as many toys from the bedroom as possible, and this comes back to something we were speaking about, which is how does your brain associate itself with the bedroom and sleep? And if there are sort of lots of toys around the bedroom and sort of these stimulating triggers, even a child's mind will learn that the bedroom

isn't necessarily the place where sleep happens. It's a place where sometimes sleep can happen, but sometimes, you know, exciting play can happen too. And by removing those toys out the bedroom, they seem to find an improvement in sleep. And then also the other component is physical activity and by removing those toys at the bedroom, they seem to find an improvement in sleep. And then also the other component is physical activity during the day and also daylight. I think I've spoken at times both in the book

and in public about how we are typically a dark deprived society at night, and that's true, and that darkness is critical at night to release a hormone called melatonin to help regulate our sleep. But I actually think I've done a very bad job of speaking about the opposite which is the critical importance of light during the day and the some data now starting to emerge that how much light that you're exposed to both as an adult and as a child can actually promote better sleep at night. So thinking about wake and sleep as sort of really nice load,

valleys during the night and high peaks during the day, you want lots of darkness at night to help you get deep sleep and that's the same for children. And then you want lots of light during the day to take you to a nice peak of wakefulness and sort of keeping it in that sort of sinusoidal wave will help you rather than having just this sort of more flat line where you know were constantly stuck inside during the day so your brain is confused it sort of gets this electrical light which is nowhere near as powerful as daylight so it's not quite sure what's going on during the day, and then at night we switch those lights back on and it's confused again, is it nighttime, is it daytime, same confusion

for children too. So those things can typically help with child sleep and also human sleep with the exception of the bedroom toys, which hopefully are not present in the bedroom. I'm intrigued by the more daylight thing is interesting. I mean, it gets me thinking, I work in rooms mostly that have a lot of windows, so there is daylight there, but it also is another reminder for me that going out and taking a walk, even if it's cold, and it can be pretty miserable here in New York City in December and January and February and beyond.

But taking a walk might have really salientary effects on a number of levels. It's very true. We often think, well, even on a cloudy day, it seems about as bright as the office that I'm in right now. That's not true. It's log orders of magnitude stronger in terms of the light even on a cloudy day relative to a somewhat vaguely well lit office room. The other thing I wanted to ask you about was the impact where upping or sleep could

have a big could could affect really positive changes on society. So school start times for kids should we be looking at later schools, start time for kids? What about medical residents? I was married to a woman who was a medical resident, and that was challenging for her to get through that. And also, we've got lots of car accidents in this country, and that's a big killer, and could more sleep help in that area too. Gosh, yeah, great topics. I think, certainly, you know, the later school start times is a really pressing issue right now here in California, Governor Newsom,

just signed into to law that for high schools. The first period, Bell, could occur any earlier than 830 in the morning, in other words, shifting the start of schools later. And there's now such a great collection of data that supports this logic. We've seen this time and again that when schools delay their start to a later point, firstly, we typically see academic grades improve. We know that sleep is essential for functions of learning and memory. So that's not really that much of a surprise that academic grades would increase

when you give the kids the chance to sleep more. What was perhaps more surprising is that we also started to see secondary effects. Firstly, we started to see that truancy rates actually decreased as well as absenteeism rates. We also saw that psychological and psychiatric referrals started to decrease. And then the other aspect was in fact that you could argue that the life expectancy

of some students actually increased. And the reason is because one of the leading causes of death in late stage adolescent teens is road traffic accidents. And here sleep matters enormously. What we've typically seen in these prospective studies when a school changes its times, pushes its times to later, in that narrow age range of just 16 to 18 years old, on average we see about a 40% reduction in car crashes that following year. A great example happened in Tedden County in Wyoming. They shifted their school start

times from about 7-30 in the morning to almost 9 o'clock in the morning. And there was actually a 70% drop in car crashes that following year. Which, you know, to me is just striking if you put that in context the advent of ABS technology in cars, anti-lock braking systems, that dropped accident rates by about 20 to 25%. But here is a simple biological solution, you know, getting enough sleep that can drop accident rates on average by 40% in some cases even more. So I think that the evidence is really quite clear if we as educators really truly wish to educate and not risk lives in the process, then I do worry that we are failing our children with this model of early school start times and we're going to get

success in delaying them. And for any parent out there, there was a study published just last year from MIT. They tracked the sleep of students across an entire semester using these sort of wristwatch devices. And what they found was that the sleep quantity and quality in the last month before the exam and the last week before the exam explained about 25% of the success of those students on the exam, on the final exam. So yes, studying is important, but up to 25% of that grade can be accounted for simply by how much sleep those students were getting. So I think it's a powerful force that we need to continue to lobby on and make change on. What about medical residents or people who... Well, actually, let me, let me, before I unleash you there.

I'll just read the aforementioned Samuel John, producer of the show. One of the producers on the show, his wife Haley is a resident. She sent this question, which I think we might have sent to you in advance. As a medical resident, she writes, when doing a call shift where I work a 28-hour shift, if I have the opportunity to nap for 15 to 20 minutes first during the night, should I do that? Or is it better to power through the night and then reset once the night shift is done?

Apparently, she notes, a more broad question could be, what advice do you have for people who work on irregular schedules or even the regular night shifts? So for night shift workers, what we're starting to see now is the frequency with which you flip, flop back and forth between day and night shifts, that's the worst scenario. So all of us in society need to be incredibly grateful for people like this. You know, if I have a burst appendix at four o'clock in the morning, I desperately want someone there to operate on me and help me. So I'm immensely grateful for their service. But we do know that night shift work is associated with worse health outcomes. We know that night

shift work that is constantly, as I said, going back and forth between different shift periods around the 24 hour clock face is the worst form of night shift work and trying to at least sort of go on the night shift for a long period of time and then come off for a long period of time or long as you can, that seems to be the better approach to that. Coming back to medicine in general, the data is actually quite powerful. Firstly, we know that medical residents who are working a 24 to 30-hour shift can make upwards of 460% more diagnostic errors in the intensive care unit. We know that if you're having elective surgery and the attending surgeon has slept less

than six hours in the previous 24, there is a 170% chance of a significant surgical complication happening relative to a surgeon that's been well slept. And then finally, there was a fascinating statistic coming from a study at Harvard Medical School and it brings us back to car traffic accidents. They found that medical residents after working a 24 to 30 hour shift when they finish that shift and then they get back in their car and they drive home, they are 168% more likely to get in a car accident themselves driving home because they are under-sled, finding themselves perhaps back in the emergency room from which they came,

but now as a patient rather than an attending resident. So I think that area is an area that needs to have change. We've seen some of that change, but I don't think it's quite enough yet based on the data. I mean, the idea of irregular schedules is the problem of a regular schedule resonates with me because I, one of the things that I think skews my data is that

there are Friday and Saturday night, I don't get a lot of sleep because most nights during the week, I go to bed at 10 or 11 pretty regularly, but on Friday and Saturday nights, I try to go to bed much earlier, and I have to be up at 3.45 to anchor weekend, good morning, America. A job I love, but the sleep ramifications are quite severe. I wonder if you can see that in your data on sort of, you know, that those nights it dropped precipitously on those two nights and that's exactly what was happening, but yeah. What would you recommend? Because I'm not

the only one, I mean, a lot of people have irregular schedules. It's so challenging and again, I don't think there are any simple solutions here other than just to simply be aware of the science. I mean, I think, you know, one of the problems I have is when you provide this type of data and the issues around insufficient sleep, I want the public to be aware of it because I think knowledge is not necessarily a burden and I'm not trying to tell anyone how to live their life. I just want to empower you with the knowledge and then people can make their own decision. But I think it is one of those difficult things where if that is your profession and it's a job that you desperately love and you're incredibly good at it, how do you think about

balancing those two tensions? Because what you essentially experience every weekend is something that we call social jet lag. And this typically happens in a less extreme version where people are working during the week that are up early and they need to sort of go to bed early. And then come the weekend, they sort of sleep in late and they're awake in the night, sort of they go to bed late, they wake up late. And then come Sunday evening, they have to try and drag their body clock all the way back by maybe 2 or 3 hours.

And that's happening every weekend, and you have a version of that social jet lag too, but it's actually professional jet lag in this regard. But to put that in context, if you're trying to shift your body clock every weekend by 2 or 3 hours, that's the equivalent of you flying back and forth from San Francisco to New York every weekend from a biological circadian perspective. And that really can be, you know, quite torturous on your biology. And we know that people working night shifts do have significantly higher risks of things such as diabetes and obesity and the some evidence there regarding cancer as well. In fact, I believe the World Health Organization has classified nighttime shift workers a probable cost

inagin because of the association between that circadian sleep disruption and cancer risk. You said a few paragraphs back, something about not wanting to tell people how to live their lives. I think you're in a tough position from a communication standpoint. I know you've referenced not wanting to be the sort of grim sleeper. There are a couple things that have been worth exploring here. One of them is that, you know, wearing this ring has been humbling for me because I do a lot of things right.

I don't drink alcohol or caffeine. I meditate quite a bit, in fact, right before bed. I stretch right before bed. I have a cooling pad on my bed. I keep the room cool. For your advice, I don't expose myself to a lot of light before bed. You know, I wear a retainer. I, I don't know, lots, lots of things that are would seem to be to up my odds

of having a healthy night's sleep. And yet I'm not cracking seven hours that frequently. And I do feel a certain sense of like helplessness creeping in and I can imagine many listeners do as well. It's so difficult. And I should note by the way that, you know, I'm no poster child for sleep myself, you know, I do all of the things that you do too. And I, of course, know a little bit about sleep and hopefully how to get it. But I have nights where I struggle with sleep as well I have phases of my life where I've gone through insomnia because of a number of different triggers so I know how difficult it is and I know you know I'm the worst person I essentially knowing all that I know when I'm not sleeping well, I become the Woody Allen neurotic of the sleep world. It's terrible, you know, I'm lying in bed and I'm thinking, well, my dorsal actual

prefrontal cortex is not shutting down. I'm not sort of tamping down my erexin, chemicals in the brain and melatonism. And at that point you're dead in the water for the next two hours, it's a disaster. So I genuinely feel for people and I think it's been, you speak about having a humbling experience and I'm glad the ring has had that effect. I think, you know, it comes to something we often say in medicine, which is what gets measured, gets managed. And I can ask you how well did you sleep last night and you could tell me, but if I were to say, well, how well did you

sleep last Tuesday and the Wednesday before that, but if I were to say, well, how well did you sleep last Tuesday? And the Wednesday before that, and the Saturday before that, it's very difficult for us to know what our historical record of sleep has been and how we actually should think about our sort of trends. And I always think it's much better to follow, you know, trend lines than it is headlines. And that's why if anyone has had a bad night of sleep, let's not focus on it. Let's just say last night was last night, let's look to the future and just let's try to make a trending improvement overall. But to come back to your point, you're doing so many things right, what could be the other aspects that are coming in to play. One of them is the difficult issue of just getting older.

That as we get older, it is one of the most potent physiological signatures of aging, which is that our sleep gets worse. And we've done a lot of work in this area. We know in part why that's occurring. I do think, however, that this weekend, weekday difference between your sleep is another thing to keep in mind. I think that that can be confusing your body and specifically your body clock, your 24 hour circadian clock.

And that's why you could have less optimal sleep efficiency than you are nevertheless capable of even at age 50. And then also, I think, the other factors of what is your chronotype, are you sort of sleeping at the time when you naturally would like to sleep? I know that's so difficult when you have a family and you have a job and those forces will prevent you from that luxury of just sleeping biologically when you want. So those aren't necessarily solutions, but they are at least perhaps reasons that may explain why that sleep efficiency is a little bit lower

than we would wish for. What I'm hearing you say mostly is it's good for people to have the information and that's your job to give people the information. And once you're informed, really try to do your best. Yeah, exactly that. And, you know, for those people who are anxious about sleep, I think, you know, trying not to sort of catastrophize and think it's a lost cause. If you really are struggling, there are now some fantastic programs that can really help people with insomnia and one in particular which is called cognitive behavioral therapy for insomnia or CBTI, cognitive behavioral therapy for insomnia. It seems to be just as efficacious as sleeping pills

in the short term, but what's better is that when you start working with your therapist, not only do you go back to the bad sleep that you are having, which is what happens when you stop taking sleeping medications, you actually continue on that journey of good sleep. And so there are helpful methods out there that people can embrace if they want to, but also just try not to get so overly anxious about sleep that ends up being counterproductive for some people as well, of course. And that's one of my greatest fears. I still struggle. I don't know the right balance yet between being a communicator of the science of sleep and truthfully telling people about sleep. I don't want the World Health Organization or the CDC to stop publishing material about the deleterious effects of substance abuse or stress

or obesity. But you know if I'm stressed and naturally I am an anxious person and I read Robert Sapolsky's book that you know Zebra's don't get ulcers and that you know provided me in great detail all of the health that provided me in great detail all of the health consequences that were happening because I was a stressed, anxious individual. Did it make me more stressed? Yes it did.

But did it motivate me to try and make behavioral changes to try and reduce my physiological stress and lower anxiety? Yes it did too. And so I still don't know, I'm still finding my way as, you know, I'm just a scientist and I'm for the most part, a very private person. It's not very easy to be in public and communicate. But I do feel passionate about sleep and I do think that there is, it's a message that unlike diet and exercise has yet to have its time in the public spotlight. And I hope that I can try and do a little part of that.

But I struggle with knowing that raises edge balance between being helpful to people versus, you know, causing anxiety and stress. A comment, and then two last questions. My comment is, in my opinion, actually, you're walking this line very nicely, and which leads me to I'm very nicely, which leads me to my penultimate question, which is for those of us who have just spent several hours listening to you and are tempted to go, you know, light our hair on fire and talk to everybody we know about the importance of sleep and you know, convince our partners that they need to sleep board, et cetera, et cetera. How do we do that without, you that without making everybody mad at us? I think trying to do it in an interesting way is always helpful. But the best piece of advice I got was actually from my partner, which is, as I was starting

to release the book and realize that I was beginning at Journey as a public communicator of science. She told me something that was great, which was, don't give people rules, people don't respond to rules, people respond to reasons, not rules. And so you can tell people that yes darkness at night is important, it's important to keep a bedroom cold, alcohol and caffeine, it should be avoided. But don't stop there, explain the mechanism, explain the reasons behind those things. That's when I think people connect with the information and realize why they're being told to do what they may want to do. And so I think if you're going to be, you know, a sleep ambassador out there, simply telling people you need to do this

and you need to do this and you need to do this is usually not going to go down very well from my experience at least, but explaining people or explaining to people the underlying reasons behind those rules, that's when people I think that the eyes light up, they get this connection, they say, well gosh yes, I've definitely found that when I have alcohol, you know, it seems to knock me out, but then I wake up many more times throughout the night and I don't know why I feel, you know, so unrefresh the following day, I never made the connection, I didn't realize alcohol fragments your sleep, I didn't realize that it's a sedative and what I'm experiencing is not sleep, I'm just simply sedating my brain and

sedation isn't sleep. And that's when people I think connect and bond with you and feels though you're not simply wagging a finger, but you're genuinely and authentically trying to help them. Final question. The first nine days of my sleep data took, were from a retreat, a meditation retreat that I was on. And the data was pretty weird.

And I just wonder if you had any thoughts, it would be, it looks like my sleep was quite fragmented and short and actually sometimes it's gave me more credit for sleep than I deserve because it was saying that my meditation was sleep. That's right. And sometimes I do fall asleep during meditation, but there's no way

and I was wearing the ring all day when I was in retreat. And I was having, especially toward the end of the retreat, very clear, vivid meditation sessions. And I know I wasn't asleep, and yet the ring was registering it as sleep. So there was there was a lot there from my view. One was thinking that I was sleeping when I was in deep meditation. The other was that my sleep, I was not sleeping much at all while on retreat, which is not uncommon, and yet I felt perfectly well rested. So I think this is where we're getting to the limits of what these types of devices at present can actually do. The algorithms usually use a combination of movement as well as your heart rate and your respiration rate to try and determine is this person asleep are they are awake and if they are in sleep what stage of it

are asleep are they in. And it seems as though by sitting in a very still position meditating where your heart rate starts to decelerate and your respiration starts to decrease, it falls the ring into thinking, actually this person seems to be asleep. And that's a very harsh criticism because I think any device, any sleep measuring device would fall into that. It's not necessarily this ring's fault. I think you would see that with many of the other sleep tracking devices. That's where if I had electrodes on your head, I would still be able to tell, okay, this person still has wakefulness in them. They're not asleep. They may look in a slightly odd state of wakefulness. This beautiful thing that we call meditation, but it certainly doesn't seem to be sleep. And what about the fact that I wasn't getting much sleep?

And yeah, I asked you about this in the first part of our interview. It's very common on meditation retreats for people to only sleep three, four, five hours a night and be quite awake. I mean, the word Buddha translates into awake. What do you make of that? I think it's fascinating. I know Richie Davidson, who you are good friends with and well connected with. He's done some studies out at Wisconsin with another sleep research called Julio Tanooni.

I just don't think we have good enough data yet to really understand what is going on with meditation. I've heard this so much as I've been speaking with the public people will say, you know, as I go on these retreats, my sleep need typically decreases, is that because, you know, there's, for example, a change in the way that you're eating, and is it the change in the eating that sort of changes? You know, is it that you're eating and is it the change in the eating that sort of changes, you know, is it that you're eating less and typically when people start to eat less and when they fast, that usually is a trigger for the brain to actually stay awake more because from an evolutionary perspective, when food has become scarce, the animal is in danger. So the animal releases a chemical

called erexin that is wake promoting. It decreases the releases a chemical, a chemical called a rexin, that is wake promoting. It decreases the amount of sleep and it allows them to spend more time foraging and a broader perimeter for food. And sometimes when we go into a state where we're eating less or we're fasting, it is telling the brain artificially, my goodness, food has become scarce. So I'm going to release this chemical and keep you awake longer. So it may not necessarily be simply the idea that often people say to me, which is meditation is replacing my sleep and my sleep need has decreased. I think that is a possibility, and I think we need to explore that. But there are also these other possibilities, other things that are changing in and around

a retreat that could also be the trigger. I just don't think we know yet, but it's something I hear quite commonly, and I think often those things turn out to have some degree of truth to them. You know, cliches are often cliches because they're typically true. Next frontier of research. Indeed. Matthew, I just want to say in closing here, I really appreciate all the time you've given to the show and to our audience, I think you to say in closing here, I really appreciate all the time you've given to the show and to our audience. I think they're going to love this. I really appreciate the work you're doing. I agree with you that we know a lot about exercise and diet and to a less extent

meditation, but sleep has not gotten the airtime it deserves. So good on you for doing this work. Thank you. Thank you for having me on. Thank you for giving me the opportunity to speak to the public about this. You know, I do want to try and help people, but I can only do it with fantastic partners who allow the message to be communicated to their audience. And this is the gift that you've given me. So thank you so much, Dan. Sleep well. I will really appreciate all of his time. That was great interview. Had a big impact on me personally. Let's do some voicemails as teased at the top of this episode. We've got a ranger this week, orange A Sofer, who's been a previous guest on this podcast. Episodes 28 and 165 and is a very popular teacher on the 10% happier app and he's got two great courses up on the app one called

Relationships and the other about working with emotions So check him out on the app in the meantime He also has a bunch of meditations up on our popular sleep tab So he's we got him to answer three questions related to sleep from you. Here's number one. Hey, Dan. Bill here calling from Fort Lauderdale, Florida. I have a question about building a meditation habit. I'm finding that sometimes when I'm doing a guided meditation, particularly a little farther

into the meditation, maybe I'm doing a 15 meditation and about eight minutes. And I find myself sometimes falling asleep. Is that a horrible thing? Am I going to go to meditation jail for doing that? When I do, you know, wake up usually at the end of the 15 minutes, I feel extremely refreshed and I feel like it was a positive experience. But I'm just not quite sure how I can get a refund on that or what I should do to prevent it. Thanks a lot. Bye. Hey, this is Oran J. Sofer. Thanks for the question, Bill.

It's a great question. And also a really common experience. So if you think about it, when our eyes are closed, our body is still and we're relaxed, most of the time in our life that means go to sleep. So it's really common when we're meditating and we start to feel more relaxed and calm that our body gets the message, oh, it's time to go to sleep. So, it does take time with meditation to learn how to be still and relaxed, yet still

have a quality of wakefulness and alertness in the mind. There's kind of an art to it. Now it sounds like you're finding the meditations, energizing and refreshing in the end, which is a really good sign. So what I would say is try to pay a little bit more attention to things like your posture during the meditation. You might sit up a little bit straighter. You can also focus more on your in-breath, which is naturally activating. So you're bringing a little bit more energy into your body. Your out-breath is naturally going to be more calming and settling. So if you focus on that, that's going to tend to take you more into that zone of feeling a little bit lulled and moving

towards sleep. Another thing you can do is try to turn the volume up a little bit on your level of interest in what's happening. So we don't fall asleep in life when we're actively engaged in something, watching a really interesting movie, having a conversation. So see if you can start to relate to the meditation itself with a quality of really alive interest. If you get curious about the breath or whatever meditation you're doing, that's going to bring more energy and help you stay awake too. The last thing you can try Bill is to reconnect with your sense of purpose or motivation for meditating. You know, why are you doing this? When we feel a strong sense of purpose,

that also brings energy into the meditation. So thanks so much for your question again, and hope this is helpful. Good luck with the practice. Big thanks to Orrin and Bill on that. Here is Voice Mail number two. Hey, Dan. My name's GC, I live in Reno, Nevada.

I gotta say, man, love your show. I love what you're doing out there. But my question will be, I started meditating at night, and I've noticed that I've had a significant increase in dreams. I do about a 20-minute practice at night and a 20-minute practice in the morning. I'm just wondering if you've ever heard, if that was a typical experience,

or if there's any literature or anything out there, like that, that'd be great. Thanks, Dan. Thanks so much for the question, JC. It is really common as a matter of fact. I don't know if there's been any research on increase in dreams with meditation, but there is a lot of literature about it within various meditation traditions. So there's a whole form of meditation practice, for example, in some Tibetan traditions called dream yoga, where one consciously and intentionally practices to have lucid dreams and remember your dreams and so forth. You might be familiar as well.

There's forms of psychotherapy, like Jungian analysis that also work with dreams. So for me, in my own practice, I've certainly experienced that, and it's pretty easy to understand why. You know, meditation practice heightens our awareness, and it sharpens our senses. So it would make sense that that increased awareness and sharpness would start to carry over into our dreams and result in more vivid or deep or captivating dreams. Meditation also tends to help us to process things that might be unresolved in our psyche. Emotions, things from the past, difficult experiences maybe that we haven't dealt with. And even if that's not happening consciously in your meditations, things can be

shifting or getting worked out in the background. And sometimes what can happen is our mind will start to work things out through our dreams. And it's as if the meditation practice is sort of priming the ground or laying the conditions for our subconscious to begin to work things through while we're sleeping. So just a few tips if you're interested in working with it, when you notice that this is happening, it can be interesting when you wake up in the morning or even during the middle of the night after a dream to reflect on the dream. And just take a few minutes to think about like what was the overall emotional tone or quality of the dream. Oftentimes there's a message there just in how we're feeling either in our life or about a particular situation. You might consider like if there are any words or images that you remember that stand out that have particular or images that you remember that stand out that have particular force or power to them.

And then you would just kind of consider what do those bring to mind when you think of that word or see that image, what's the association that comes. And what I find in myself is if I take a little time and just reflect on it, usually some kind of a meaning or a connection becomes clear. Not all of the time, but much of the time. You can also get better at it, taking the time to reflect on the dream. You start to get a feeling for how your psyche is communicating and processing things. Thanks so much again for the question, JC. Thanks for your practice and good luck with it.

Thank you, Orrin and JC, and now VoiceMail number three. My name is Jeff out of the Boston area. I'm a meditator about six months. I have been trained in mindfulness and locally, and I've been practicing almost daily. And my question is, when I'm getting into a very deep meditative state after usually a good 10 minutes or so, I've noticed that sometimes it feels like I'm falling asleep, a pre-sleep feeling, and sometimes I even catch myself jerking awake with a little hipnick jerk.

And so I know, in most cases, that I am actually on the edge of falling asleep, I'm wondering that should I be meditating at a level where I'm very, very what I would consider deep and almost zoning in almost a pre-sleep condition or should I be as I am in other times, very wide awake, very aware of what's going on in my practice and being really mindful in what's around me or should I be again more in a transplant-like condition?

Thanks very much. Thanks so much for the question, Jeff. That's a great question. The name of the game here with meditation is balance. We're really looking for balance on many, many levels. We want the posture to be balanced. We want to balance our sense of trust with the quality of skepticism and investigation. And we want to balance the quality of wakeful

alertness that you're talking about with that sense of real tranquility and ease. So meditation practice involves two parts. On the one hand, there is this aspect of it that's really about soothing and nourishing ourselves and just kind of recovering from the stress and the incessant friction of life. So I think it's helpful and important to allow ourselves in meditation when we do feel at ease, when we feel those feelings of pleasure, even a little bit of drifting, to not jerk ourselves away from it, to let yourself be nourished by it, let it replenish you. At the same time, we don't want to be drifting off to sleep.

Over time, that's going to be counterproductive. Every now and then, yeah, of course, you know, we drift a little bit. You catch quick catnap, great, no worries. But if that's what's happening all the time in your meditation practice, I would encourage you to try to balance that with more awareness because ultimately, in these two parts of the meditation, there's the nourishing, calming, kind of settling part, but then there's also the understanding, the wisdom, the clarity, and really the sense of calm and nourishment is in service of the transformation that comes from wakefulness, clarity, and understanding.

And that kind of wisdom only develops when the mind is aware and awake. So you want to see if you can bring in more of that quality of alertness without it being uptight, without it being frenetic or forced. So that the two start to blend together. You have a really clear, steady, bright awareness that's also easeful.

That's really what we're going for. So one of the metaphors that I like to use is you can think about a radio receiver, like on a stereo, on a high-fi stereo, where you've got the bass and the mid and the treble, and you've got all these little dials that you can adjust. So what we're trying to do here is we're trying to become more familiar with the energies, the qualities and the intentions in our own mind and body, the amounts of energy and interest and curiosity and ease and kindness and patience. And just adjust those ever so slightly here and there so that we find the right balance

and things come into focus on their own. So it sounds great. I would say keep going with it, keep investigating, being curious, and you'll find that balance on your own in time. Thanks so much for the question Jeff, and good luck with it. Big thanks to Orrin for joining us for this week's special voicemail section on sleep. And big thanks to the folks who put this show together. Ryan Kessler, Samuel Johns, Grace Livingston, Lauren Hartzog, Tiffany O'Mohundro.

And thanks to you for listening. We'll be back next week with another episode. Hey, hey, prime members. You can listen to 10% happier early and add free on Amazon Music. Download the Amazon Music app today, or you can listen early and ad-free with Wondery Plus in Apple Podcasts. Before you go, do us a solid and tell us all about yourself by completing a short survey at Wondery.com slash survey. you