Modern Wisdom - #027 - Dr Greg Potter - The Definitive Guide To Sleep

Episode Date: August 27, 2018

Dr Greg Potter is a PhD graduate at the University of Leeds & Content Director at HumanOS. His research focus is on sleep and chronobiology; looking at circadian rhythms, light-dark cycles and the potential for meals to entrain peripheral circadian clocks. The unsung hero of health is hiding under our pillow every night and today we learn just how important a good night's sleep is to our short & long term fitness, our mood, cognitive output, physical performance, injury risk, weight and pretty much everything else. Discover the best approach for dealing with sleep deprivation, how to optimise your sleeping environment, how meal content & timing can affect our circadian rhythms and a lot more. Further Reading: Follow Greg on Twitter: https://twitter.com/gdmpotter $1 for 1 month of Premium Membership at: https://www.humanos.me/ (Code: modernwisdom) Check out everything I recommend from books to products and help support the podcast at no extra cost to you by shopping through this link - https://www.amazon.co.uk/shop/modernwisdom - Get in touch. Join the discussion with me and other like minded listeners in the episode comments on the MW YouTube Channel or message me... Instagram: https://www.instagram.com/chriswillx Twitter: https://www.twitter.com/chriswillx YouTube: https://www.youtube.com/ModernWisdomPodcast Email: https://www.chriswillx.com/contact Learn more about your ad choices. Visit megaphone.fm/adchoices

Hi friends, how was United Sleep? Was it good? Hopefully after today's episode it's going to be better. Today we're going to speak to Dr. Greg Potter who is a PhD graduate from the University of Leeds and a specialist in sleep. His work has been featured absolutely everywhere from Reuters to Time Magazine, Washington Post, USA Today, Daily Telegraph, BBC Radio. He's, he's pretty prolific. And he's also the content director at humanos.me. Now, the guys at humanos haven't sponsored this episode at all. However, it is a fantastic service that you should check out and later on in the episode Greg explains what it's all about. But if you do want to go and have a look, treat the sign up and with the code

Modern Wisdom, you can actually get their premium version for one dollar for the first month and there's no minimum term. So check it out. Now many people take a lot of time researching their diet or their exercise and making sure that they're trying to live a healthy life but quite a lot of us overlook just how important sleep is in this equation and having read Matthew Walker's book Why We Sleep I was struck by just how little care I was giving to my sleep habits. The implications on your health, mood and performance both in the short and long term are pretty drastic and I don't think that there can be enough weight applied to just how important sleep is. Now, hopefully today, we're going to convert you from a non-believer to a sleep paragon who is armed with some new tools

to improve their sleep and a passion to actually make it better. Essentially, what I'm saying is that if you live a long and healthy life with all of your faculties still intact, at the ripe old age of 95, you can be on your deathbed, incredibly mobile and full of zen, and look back at this podcast and think, thanks Chris and Dr Greg. Dr Greg Potter, welcome to Modern Wisdom. Thanks very much, it's great to be here. How are you today? Yeah, I'm very well, how are you? Fantastic, thank you. Did you get a good night's sleep? Not bad. I've been up for a while. By who's standards? Did you have a not bad night's sleep? By my own not particularly good standards, rigorous sleep standards, right? Well, I didn't set the bar too high, but the last few weeks have been a bit ripe at times. Is it do as I say not as I do? Yeah, it's one of those. So can you

explain to the listeners what your speciality is, what your what your focus on in your research area? Sure, so I have just passed my PhD. Congratulations. Thank you very much, which was at the University of Leeds, and I'm in Leeds right now, and during my PhD I focused on sleep, diets and metabolic health in UK adults. So I focused on studies of human beings and in my PhD there were several different parts. It began with the validation of a dietary recall method. So if a nutritionist is interested in how diet affects health and risk of various diseases, then they need accurate ways of capturing what somebody eats and And to that end, you need to validate the tools that you use. And I was involved in the validation of one of those

tools, which is called My Food 24. And it's the first validated tool designed for you, specifically with adults in the UK. It's very comprehensive and that people is just being published. And I then used that data set to look at associations between when people eat relative to when they sleep and their metabolic health. I also did some work looking at how sleep duration is associated with risk markers that are associated with diabetes in the UK and also how people eat. And then at the end of my PhD thesis, I did a randomized control trial of long-term melatonin supplementation among people who are at high risk of type 2 diabetes. So let's say, for example, Chris, that your dad has type 2 diabetes, that would increase

your susceptibility to that disease. Question was can you use melatonin as a pro-calactic agent against you developing type 2 diabetes? So just wrapped all that stuff up and now I work for human OS as content director and I've been working with those guys for at the last 18 months or so and I've more or less been working with those guys for the last 18 months or so and have more or less been working full-time for the last four months. And the CEO also has a strong background in sleep research so he's here then in common. You're in good company then. Yeah, I would say so for sure. That's fascinating. Well, I mean, there's an awful lot an awful lot to go through there But I know that a lot of the people who are listening will have heard me

mention a number of times Matthew Walker's book why we sleep I think that's probably up there with my most ever listened to podcasts between him and Joe Rogan and It's gonna be it's gonna be really really interesting to be able to dig into what I've heard and and read about so much and try and actually elicit some of the answers that I think are maybe missing from my body and knowledge and then give the listeners a little bit more of an understanding of why sleep is important and what it does to people. And then I'm super excited to talk about human OS as well. Earlier on today, I had a pretty comprehensive browse of the site so we'll be able to finish up with that

at the end. So a lot to get through today. Fascinating, sounds good. Fantastic. So to get started, do you know why we sleep? No, not really. That's great. So, it's a long-standing question in sleep research, and there are many different ways that you can try and address it. What I'll say is that there's no real consensus right now. And I think it's worth thinking about why we sleep from evolutionary perspective. And when you think about sleep, and this is something that Matt discusses

at length and with great clarity in his book. Sleep's very strange and while you're asleep, you can't eat, you can't gather food, you can't have sex and you're vulnerable. And for all of those reasons, there should have been very strong evolutionary pressure against the development of sleep-life behaviour. You're incredibly vulnerable, right? Yeah, absolutely. But as far as we can tell, more or less all species studied have sleep-like behaviour. We spend a third of our lives doing it. So the question is, why is that the case?

And I think that in reality, it probably serves different functions in different species. What's interesting is that different organisms have very different sleep patterns, both the time you have their sleep and also how long they sleep. And there are various things that seem somewhat predictive of sleep. So things like the complexity of social networks, nervous system, complexity of the type of diets that animals consume. the system complex to the type of diets that animals consume, but no one thing is strongly is a strong determined of sleep in animals. So anyway, what happens during sleep? Well, it's a period of adaptive inactivity and one of the functions is probably to optimize the timing and duration of abouts of activity to do things like produce a risk of predation

and also to ensure food acquisition. Another function is energy conservation, but actually if you look at the amount of energy that you save by sleeping versus just being awake and relatively inactive, it's very, very small, so that's not a particularly persuasive. So evolution hasn't given us this because it lowers our requirement for food. So evolution hasn't given us this because it lowers our requirement for food. Doesn't seem to be the case. Not only humans, if for example you look at all of the studies that have been done on the effects of sleep restriction on energy expenditure, the effects are negligible. We're speaking about the amount of energy that's contained in the slice of bread. Just have another bit of bread you'll be fine, honestly.

Stay up all night, off your face on bread, and then the next day you'll be fine. Well, bread has gluten in it, and that will probably get... Oh, no. I'm going to trigger everybody. So anyway, there are also different things that we pass through during sleep and each of those serves related but distinct functions. So if for example you look at non-rems lead, non-rem meaning non-rapid eye move and there are three stages at this type of sleep, each of which becomes progressively deeper by which I just mean that it's harder to wake someone.

which becomes progressively deeper, which I just mean that it's harder to wake someone. Don remeber sleep. There are processes like nervous system restoration, energy conservation, and pruning away connections in your brain that you use during the day, but weren't highly used, and therefore don't seem to be necessary to hold on to. During this stage of sleep, there's also a kind of waste disposal system that becomes active in the brain. And there was a study that's published about five years ago showing that during sleep and mice the plumbing in the system effectively opens up and cerebral spinal fluid washes toxic debris out of the spaces in the system that's accumulated during the daytime. So that seems to be one of the functions of that particular type of sleep.

Does that explain an increase in clarity of thought the next morning after you've had a good night's sleep to one degree? Yeah, it would do. It would do absolutely. And then another stage of sleep that you'll enter after that deeper stage of sleep is the stage with which most people are most familiar. Rapid eye movement sleep, which is that stage in which you dream. It's called rapid eye movement because of the ways that your eyes start from side to side during the stage. It's quite strange in that even though parts of your brain are as much as 30% more metabolically active at this time than they are during wakefulness, your muscles are

completely paralyzed so that you don't act out your dreams. What this creates is an environment in which you can take information that you've accumulated during the day and then consolidate it during deep sleep. And you can collide all these different sources of information in your brain to form new connections. And through those new associations, you seem to be able to generate creative ideas. And what's very interesting actually is that if you look at humans specifically, then we spend maybe 20 to 25% of our sleep in REM sleep,

which is more than any other primate, but we sleep less than any other primate. And some people speculate that this disproportionately large amount of REM sleep that we have as humans has been fundamental to the development of our intelligence and our complex social structures. So that's quite interesting. That is interesting. I'd seen the study that you're talking about to do with or want a study that related to new connections in the brain when you're asleep and recently did a podcast with the author of Make It Stick, Peter C. Brown. And during that, he said that one of the key determinants of your capacity

to learn is doing focused, concentrated work, and then going away from it and then coming back. And I think that generating new connections and viewing anecdotally, you'd say you're viewing something with a new perspective, but it seems that that's actually being reflected physiologically within the brain. Yeah, and there are probably a couple of things to touch on there. So one is learning during the day and the importance of spacing because it's been years and years, more than a decade since I looked at any of this research but in psychology there are so-called primacy and recent CFX which just means that you tend to remember what you learn at the start of a learning bout and the end of it too and you don't remember what you learn at the start of a learning bout

and the end of it too, and you don't remember the stuff in the middle so much. So what that means is that, let's say you've got six hours in which to learn, you're better off taking regular small breaks and then by doing so you create more opportunities for these primacy and recenty effects, And then while you're not doing learning, you want to take your mind entirely off the task. So that's one component to the puzzle. But another component to the puzzle is about during learning or between learning periods themselves.

OK. This is something that you want to return to later. But the way that that happens is relatively well understood. There are specific aspects of the process that are controversial and there's not complete consensus on, but it's something that's probably worth understanding because actually it is information that you can use to improve your ability to learn. That's fascinating.

Is the sleep industry of researchers, is it quite dogmatic? Are there some pretty sort of standoffish camps? I don't know how militant the sleep world is. Well, you're speaking about a bunch of academics and I'll put them quite firmly in the passive category as individuals. Okay. Never seen a fight at a conference.

Okay. Okay, that said that there is contention over some things and I think that it's often the case that somebody's view will be ingrained early on and then it will go a period of time without being challenged. And there's been this so-called replication crisis in science recently and it's received an awful lot of attention in the media. I think psychological research in particular has come under fire for the inability to reproduce the results of previously done studies. And what's nice now is that more

and more journals are necessitating that people make their data open access after publishing. So people can revisit what other scientists did to me, but they did in fact do what they said they did, and to make sure that they haven't dredged through their data and try to come up with a way of analyzing their data to support their hypothesis, rather than going in there beforehand and saying, okay, this is how I'm going to look at my research question. And regardless of what the results are, I'm sticking to my guns. Well, that's the scientific principle, right? You shouldn't be trying to make the research fit a previously held hypothesis.

That's not the way it's supposed to be. But I can imagine that a lot of people, once they've got the teeth, once they're certain about something conceptually, they want the research to then reflect that. Yeah, and an issue is that it's difficult to publish negative findings in scientific journals. By negative findings, I don't mean that they're disheartening or anything like that.

I mean, there's no effect of A on B. Yeah. And it's less glitzy, right? It's not as much of a... of A on B. Yeah. And it's less glitzy, right? It's not as much of a... Melatonin doesn't affect sleep quality. Isn't as much of an exciting title. Oh, that might actually be.

But something else that A doesn't affect B, it's not as attention grabbing, right? Yeah, it's not going to be on the from page of the Washington Post anytime soon. I got you. So we understand, oh, we have a beginning of an understanding of what we think sleep is required for from an evolutionary perspective.

Do we know how much is optimal? Is there an agreed upon time? It's kind of this wives tale anecdote that eight hours is how much we need a night? Is that, is that correct? There are guidelines, but you can't take the guidelines and assume that you're correct, that they are correct for you as an individual. The guidelines vary according to how old somebody is. So if you look at young people, they need more steep than adults. And for adults, according to the National Sleep Foundation on average we need 7 to 9 hours per night but there is relatively substantial variability between people in sleep

need and one other thing that I'll add is that the amount of sleep that you need is a moving target of sleep that you need is a moving target. So I don't know what your experience is, but for me, for example, I generally find that I sleep more in the winter than I do in the summer. And I think that's probably somewhat related to the photo period. Also, if I'm going through a period in which I'm exercising particularly intensively, then I'll need more sleep. If I have a cold, then I'll need more sleep. If I'm stressed about something and I have a deadline on the horizon, then it's just as if the alarm clock in my brain just comes online a little bit earlier. Yeah. For that reason I sleep less. So even though we have these generic targets, I think that actually fundamentally we have these generic targets, I think that actually fundamentally, you give yourself the opportunity to get the sleep that you need by getting in bed on time. You focus on

preparing for sleep as well as possible by getting in the right framed mind and also supplying with your body with what it needs, ensuring that your environment around you is conducive to good sleep. And then you don't wake up to an alarm and you see how long you sleep. And it sounds facile to explain that way, but I do think that that is how it is. With all of that said, 79 hours is a good baseline for most people. And we understand more and more about some of the things that do influence why some people need more or less sleep. But some people I think historically have thought that there are those lucky few out there the Margaret Thachs of the world who need three hours of sleep

and they function just fine and that just doesn't seem to be the case. So of all of the genetic variants that have been identified so far, the particular variant that's associated with the shortest sleep phenotype is on average a variant that has adults sleep about 6.2 hours per night, which I think is probably far more than most people would expect the shortest leaps to sleep. Is that the phenotype which is present in the same percentage of people that get hit by lightning? Is it the incredibly rare one? You hit that sounds right.

Is it like I think it's one in 120,000 or something like that? It's very repaid. Yeah. Right. So I think it's safe to assume that you don't have that. It's like for the vast majority of people that are listening. So what that means is you need to be aiming for between seven and nine hours. And just how important is sleep to our short term and long term health? That's a very big question.

Okay, so where would you like me to start with that? We can speak about metabolism or... Let's take it from the top. Wherever you think's best to set the scene and go from there. Okay, well, there are different ways of looking at it. Obviously, you can't have an intervention in which over a very long period of time, you have one group of people short in their sleep and you have another group sleep as much as they like. So, in order to get at the effects of sleep on the population level, people use epidemiology, the study of populations. And typically those types of studies will just have people answer questions about sleep and then researchers will associate how long people report sleeping with various health outcomes and preferably they will also follow them up over time. So in those circumstances

prospective studies like that can be used to see whether short sleep at baseline predicts greater development of chronic disease further down the line for instance. So that's one way of looking at things. From the fact is that there are all sorts of confounding variables. It's self-reported, right? It's hardly a scientific approach. Well, it is a scientific approach, but it's not objective. Well, it is a scientific approach, but it's not objective. Okay. That's the point. And in order to get a more objective handle on the effects of disrupted sleep, on various

outcomes, you need to look at sleep studies in which people come in the environment, into the laboratory environment. And they are given a certain amount of time in bed and then you assess various outcomes of interest. So if we start with metabolism for example, then we've known for about 20 years now that as little as five nights of shortening somebody sleep to four hours per night, results in otherwise healthy young people temporarily becoming pre-diabetic. Wow. Not only that, they also tend to eat differently. So that effect is seen when somebody's

diet is held constant. But if you let people choose what they eat, then on average, restricting somebody's sleep duration to a period of say four to six hours per night tends to increase the amount of energy they consume by about three hundred and eighty five calories a day. Okay. Which doesn't sound like much, but of course health is the consequence of your behaviors over a long period of time. So the cumulative effect of all of the small impacts adds up to something meaningful. And 385 calories a day, over the course of the year, that's the amount of energy that's stored

in about 18 kilograms of fat tissue. And I'm not saying that. I'm not saying that. You would gain 18 kilograms of fat tissue because you have this liposetant in your brain which will actively try to defend how much fat you carry so it's relatively unwavering but you are likely to gain weightless, put it that way. So sleeping less means eating more and I'm going to presume that people when they are tied, I know for myself, if I've had a really bad night's sleep or if I haven't slept enough,

I'll reach for less healthy foods as well. That's exactly right. Yeah, so it's not only the amount of food that people are eating, but it's also the quality of food that seems to be affected by sleep loss. And in the last maybe decade, people have started to look at the effects of sleep loss on patterns of activity in the brain in response to food stimuli. So for example, you can have somebody come into the lab. You can completely deprive them of sleep over the previous evening and then

show the images of cupcakes and cookies. And you can compare their brain activity in that situation to when they're allowed as much sleep as they would like. And after the sleep deprivation, areas of the brain are involved in motivation and reward to acquire food. Lides up like Christmas tree. And after only that, but the prefrontal cortex, which is the most recently evolved area of the brain.

You can think of it as the brain CEO or the part of the brain that lets you do the right thing when it's more difficult things do, is less well connected to other regions of the brain. So it doesn't have the ability to override those urges. And some of the more primitive parts of the brain and the limbic system tend to be more active too. So you have this double whammy of brain activity that makes it increasingly hard to avoid succumbing to the temptations of things that our bodies are hardwired to gravitate towards, like lots and lots of calories. That's interesting. So I know a lot of my friends that do sports and some of them will be prepping for bodybuilding competitions, fitness shows, cross-fit competitions that are coming up,

specifically when they're in a deficit, if they're dieting, hard, trying to cut before a show, I know that they struggle with their sleep. So what you're saying is that the poor night sleep that they've potentially got, perhaps because of being hungry or perhaps just because of stress about the show or whatever it might be, is making the next day of deficit eating even more difficult, requiring even more willpower

to not go and get a cookie from the cupboard. Yeah, and fortunately that is a vicious cycle. That is a very, very vicious cycle. So apologies to the guys that are getting ready for shows that are listening, but you just need to go to bed a little bit earlier, I think. So what about the effect of sleep on mood? So if you look at sleep duration

and neurodegenerative disease and also various mood disorders, bipolar disorder, major depression, there seems to be strong associations there. So it appears to be the case that almost no mood disorder, in almost no mood disorder, people experience normal healthy sleep. There's always some sort of disruption. And what I'm most familiar with is the effects of circadian system disruption on mood and also how circadian rhythms are misaligned in certain mood disorders. But can you briefly explain what a circadian rhythm is for us please? Sure.

So organisms evolved in this 24 hour light dark cycle that we experience each day. Not only that, that's nested within the context of these seasonal changes in various environmental conditions. And to thrive in those environments, they needed to develop timing systems that help them anticipate daily changes in the environment, change in temperature, change in light exposure, because with that came changes in food availability

and predation risk and so on. And over the course of millions of years, almost all not all organisms, evolved these internal timing systems. And a circadian rhythm is a rhythm that has a period of about 24 hours, but it's not precise in 24 hours. These rhythms are self-sustained, so they repeat of their own accord day after day. They're persistent and they're intrainable so because they're not exactly 24 hours they need to be reset each day and the strongest

entraining agent in the environment that resets our biological rhythms as humans is the light-dark cycle and that does so by way, it's called the photon-euroendic system, but it's just the way that light is perceived by specialized cells in the eyes. And these specialized cells then relay information about light exposure to a so-called master clock in the supercarsamatic nucleus in the hypothalamus. And this master clock just sits atop where the two optic nerves

that come from the eyes to the visual chord C's is placed in its samples information about light environment. Over time, it then knows what time of day it is outside roughly. And it uses various ways of sending this time of day signal elsewhere in the body. So perhaps the best known of those is via the pineal gland and subsequently melatonin synthesis. So as light comes in to arise, this signal was then transferred back to the pineal gland via via the master clock, and light exposure, offset melatonin synthesis.

During darkness, that signal is no longer coming in, so the pineal gland synthesizes melatonin, and then melatonin relays this signal of darkness throughout the body, because many of your body's tissues have their own melatonin receptors, and through that

mechanism they know that it's dark outside and they should be performing nighttime activities but it's not only melatonin that the system uses it also uses things like changes in body temperature each day another very important hormone in the circadian system is cortisol. And if you look at the daily rhythm of cortisol, then in anticipation of waking each day, you see this big spike in cortisol in healthy people, maybe an hour or so before waking up.

And what that does is mobilizes stored energy reserves in things like your muscles, it increases your blood pressure, your heart rates, and it redies your body for the day ahead. So that's one other key agent. And then the mast cock itself also sends out all the creeds at its own substances that then reach other areas of the brain

and help coordinate the timing of all these different body systems. So circadian system as a whole optimizes your body for the needs of the present moment and in this way for example. You will be at your strongest during the daytime you will digest the system is best set to digest food during the active period and at night time your appetite will naturally wane. You'll have a dropping core temperature and brain temperature and that improves your ability to fall asleep. You will see a spiking growth hormone which will help you preserve your knee and body mass overnight and overall the net effects of this symphony if you, is to make sure that if everything is working properly, then your whole body is optimized for the needs of the present moment.

Okay, so that's what a circadian rhythm is. I'm going to guess that that requirement for light and dark to regulate our sleep is why seasons, specifically in places like the UK, where we do have quite a big disparity between summer day lengths and winter day lengths. I'm going to guess that that's one of the reasons that people may struggle to wake up in the morning or may find sleep different between seasons, is that right? Yeah, it is. There's not actually very strong evidence of seasonal differences in people's sleep patterns in artificially lit environments because everywhere you go in the UK, you can't escape a street lamp or life and buildings or whatever.

But if you take people and you haven't go camping during the winter, you have to go camping during the summer, then you will see quite rapid changes in people's sleep patterns that track changes in the light dark cycle. One thing that you mentioned there, which is relevant to move the soil is to circle back to that, is how that changes over time and how some people may find it hard to wake up a certain times of the year, or just feel worse. So seasonal affected disorder, for instance, is quite commonplace, and it's more commonplace the further from the equator that you move, so about higher latitudes. And what you find is that around the time that we transition and the clocks switch back each autumn. You tend to see a spike in people who report experiencing depression at those times.

And actually the skating system is a point at which you can intervene in order to try to help those people. Do you think that the reports of depression are to do with the single night of lack of sleep or that that is a marker that the days are getting to a length where that would occur. Yeah, I think it's probably a bit of both because that's crazy that a single change in time would elicit a response from a general population. Yeah, I think the strongest evidence of the change in time producing that kind of response from a general population? Yeah, I think the strongest evidence of the change in time producing that kind of response is daylight savings time. So during the spring time, when we lose an hour of sleep each year, you tend to see a spike in traffic accidents at that time of the year,

for example, there's also some relatively weak evidence that you might see an increase in cardiovascular incidents at that time, so an increase in things like heart attacks. Of the back of one night? Well, it's one night acutely, but of course, people have to keep waking up early. So let's say that the first night you lose an hour of sleep, and then you start to adjust to being a little bit earlier. You never fully adjust. So maybe the second week you're losing 45 hours of sleep and so on. Yeah. I think that there's a cumulative effect there over time. So I think that's probably the best evidence of that type of acute disruption to the having long-term consequences for lots

of people. But also, there is this change in photo period that seems to independently affect risk of people experiencing certain things. And I think particularly up at the polls, people are very high risk for that. Yeah, definitely. I mean, there's period entire months where the sun doesn't set. If you're ever going to be somewhere and stuff with season effective disorder, it's going to be either of the poles. So going back to moods. Is there any research which shows a link between someone with sleep deprivation and depression? That's an interesting question because actually, historically, sleep deprivation has been used as an antidepressant. Really?

Yeah, a single night of sleep deprivation. So quite often it's the case that people with depression will experience poor sleep. And if you deprived somebody of sleep over one night, then they have this really strong increase in the pressure to sleep. And then in subsequent nights they sometimes find it easier to get back onto some sort of consistent sleep schedule. Wiping the etch or sketch board clean, so to speak. Kind of. Yeah, but but also during that night of sleep loss, people's mood does tend to improve acutely and we don't really understand fully why that's so.

I haven't looked close at that research. I know that somebody who I've collaborated with University of Surrey's published some work on that. And they looked at the metabolome, which is where you basically take a biological sample. So let's say you take somebody's blood and you look at all of the metabolites that are in that blood sample at that particular time of day.

And you can take them at various points during the day and look at how the metabolites that are in that blood sample at that particular time of day. And you can take them at various points during the day and look at how the metabolites respond to various interventions, so for example, diet or sleep loss. And if you look at the effects of sleep loss, and I think that there's evidence that you see changes in serotonin signaling, serotonin metabolites, and serotonin's a neuromodulator, neurotransmitter, which is important to things like mood and sexual function, motivation, all sorts of things. But I think that the strongest evidence, of course, that serotonin is critical to that, is the fact that what's the most common anti-depressant

medication we've used is... SSR, yeah. We're up taking hivitors, which basically prolong the amount of time that serotonin is in the synapse between neurons and the brain, it reduces the clearance of the serotonin from those. So sleep deprivation does have the short term anti-depressant effects, but those effects aren't sustained over time

and actually as I alluded to before what you tend to see is that over the long-term, of course, where sleep is associated with foreign rude. And the tricky thing as I briefly touched on is just that The thing as I briefly touched on is just that often somebody sleeps poorly, but how do you causally tie that to some specific outcome in an observational study? When people who sleep poorly might be smoking more, they might experience more stress at home, perhaps they drink, they have all of these other lifestyle behaviors that negatively affect the health outcome in question. Yeah, it's very difficult to isolate, right? Yeah, that's it.

So one thing that's interesting here, is there a way that sleep scientists have been able to detect the arrow of causality between sleep and issues or issues and sleep? Am I sleeping badly because I'm depressed or am I depressed because I'm sleeping badly for instance? Yeah, I think it's easier to address the former question because you can disrupt somebody's sleep and then look at that on an outcome. But you can't improve, for example, one particular outcome and then it could be effective that honestly. Does that make sense? Absolutely. Yeah, absolutely.

If you're looking at something like diet and sleep, then you can. You could do an intervention in which some people consume a specific meal three hours before sleep for a period of time and then cross them over into another group in which they consume different meal and look at the effects of that on their sleep. It's just that if you have something like mood, then that's a much more difficult construct to try and get at. Incredibly subjective, right? Yeah, that's right. Very much so. So we've touched on sort of short and medium term effects of sleep. What about when we're talking over a lifetime

for someone who potentially does shift work or has got chronically underslapped? What are the sort of things that can happen there and then conversely what are the effects of someone who's sleeping well over that period? Yeah, so over a lifetime the best data that we have really are those types of observational data. And if you look for example at obesity then people who reports the being less than I think seven hours per night are at 45% higher odds of developing obesity later in their life. That's based on results from meta-analysis, which is a study of studies which was published last year. That's seven hours, which I think for a lot of people would they'd consider, oh well, you know, only one hour off eight and eight, what I'm supposed to get.

Yeah, yeah exactly. And of course, there could be misreporting, but when you're speaking about, in this instance, 11 studies on nearly 200,000 people, then that's actually quite persuasive. There's got to be some proof in the pudding, yeah. Yeah, I'm sorry. But then there are also lots of other conditions that you could look at. So neurodegenerative diseases like Alzheimer's or dementia. And again, you see that same type of association. Is there an increased risk?

There is an increased risk with people who report porously. Yeah, absolutely. And there are different ways in which we can think about porously too. So in this conversation so far, we've mostly focused on sleep duration, but also there's of course sleep efficiency. So let's say that you go to bed each night at 10pm and you wake up at 6am, you're in bed for eight hours, you're not going to be asleep the entire time. Sleep efficiency is the proportion of that sleep period in which you are actually asleep. So there's efficiency there. There's also sleep architecture, the way that you cycle through

the different stages of sleep. There are specific sleep disorders, of course, of which there are over 100. There's sleep timing and something that's gained more attention recently is sleep time and variability. So, consistency in when people go to bed and wake up does seem to be important. Regardless of duration and quality, just an upset in the regular cycle of the sleep times of sleeping and waking. Yeah, I think regardless of duration, I'm not sure I would say regardless of quality because actually when you go to sleep, influence the quality of that sleep.

That's related to the way that sleep is regulated. And I can just speak briefly about that if you'd like. I'd love you to speak deeply about it as I know that a lot of the guys who I work with, to give you tiny little bit of background, my job as a club promoter means that if I've tracked my sleep for around about 1300 nights using the sleep cycle app on my phone and if you look at the data, the variability that you have in my sleep and sleeping and waking time is almost 20, it's almost global, it's almost 24 hours that very regularly throughout the week, I'll go to bed when I don't have work at around about 11 o'clock or 12 o'clock

and get up at sort of between, anywhere between six and eight, but then when I go to work, I'll be working until three in the morning, I'll get home, got a bed at four, wake up at 10, or wake up at 12, and you know, this is, I'm only one person out of a massive, a massive night life industry, then adding shift workers and, you know, all manner of other people.

There's a huge, a huge proportion of the population that this will affect, I'm gonna guess. Yeah, absolutely. And if you look at shift work, for instance, and that is a former shift work, of course, then, yeah, roughly 20% of people in Europe and North America do shift work. And it doesn't just affect those people. It affects their loved ones too.

So you have all the second hand shift workers. You have to tolerate you poor shift workers who do that work. And it's really important. You wake the misses up when you get in at 4 a.m. And then that's right. Yeah. So what are the effects on shift work? And what are the effects on shift work and what are the effects of

variable sleeping and waking times on long short and long term health? Yeah, so shift work, if you look at all of the studies that have been done and then compile those results, then it's associated with all sorts of native outcomes as you might imagine. Well, give it to me, frankly, Dr. Tell me what it is. imagine and well give it lay it to me frankly doctor tell me what it is. If you look at the strength of those associations then it varies depending on the outcome but shipwork, night shipwork specifically is associated with things like obesity, diabetes, heart disease, risk, stroke, breast cancer has received some attention, certainly some cancers have stronger evidence than others. I think that whether it's associated with breast cancer has come into question

recently, because there was a large report that was published that suggested that might not beat the case, but almost everything does seem to be effective. The question is that the question is what is it about shift work that predisposes people to? That because it's a complex exposure scenario which is not just sleep that's disrupted, or circadian rhythms that are disrupted. You also have people doing all of these things and often working stressful jobs, for example,

that will also affect their risk of various diseases. So that's all important to understand. One thing just to circle back to why when you sleep affects the quality of your sleep is that if we look at how sleep is regulated, then there are two processes. And one of those processes influences how awake you feel at any given time. That's regulated by the Cadean system. And what happens is that each day you wake up in the morning and then over the course of the day you see this increase in the drive to stay awake and then around the time that you normally fall asleep.

There's a sudden drop in this wakefulness drive. The other process is the sleep process and that's a process that builds with prolonged wakefulness. So, the longer you've been awake, the more sleepy that you are. And that's not a perfectly linear effect, but that's true to some degree. And there are various physiological currents of that, and these are called somnogens. You can think of them as chemical barometers of how long you've been awake. So, as I'm having this conversation with you, these are accumulating in our brains right

now and they're increasing our pressure to fall asleep. Summarygians. Yeah. Summarygians. Exactly. And if you look at shift work, let's say that somebody does a slam shift. So they're used to being up during the week and then they have a single night shift. They get in at 5am and for the last five single night shift. They get in at 5 a.m.

and for the last five days they've been waking up at 6 a.m. What that means is that whereas at 10 p.m. the previous evening, they had the sudden drop in weight from the drive and they were desperately trying to stay awake at the start of their night shift. Now at this time of day at which they're trying to fall asleep, they're just starting to enter a period where the weight from the strive is increasing. So is there a sort of a lag, but with the sleepiness, the somnogens and the weight from the strive, there's a lag behind what's actually going on. It's got like a delay on it for it to catch up.

So there's now this big pressure to sleep because of the accumulation of these omniscience in the brain but they've missed that opportunity to sleep the time in which the wake from the strive was very low. So they've got this combination of an increasing drive to be awake but also very high sleep pressure and for that reason it's not it's not quite as easy to fall asleep as it would have been otherwise, but let's say that they do fall asleep. What will happen is that as they enter sleep,

the weight from this drive is still increasing, and they're starting to pay off all of that sleep that they've accumulated. So as somebody falls asleep, all of those somnogens that are accumulating in the brain are then paid off back to normal levels. So over the course of a good night of sleep, what should happen is that the brain is restored, you wake up next day and you've got this big increase in alertness because you now have

an increase in weight from the stride when you've paid off all of the sleep debt. The problem is that now these people, they're going to sleep at 6 in the morning and they're starting to pay off all of that sleepiness from the previous day, but they've got this wakefulness drive which is kicking back in. So now they're experiencing an increasingly strong weight drive and less and less sleep pressure. What happens? They can't stay asleep.

So maybe they get a couple of hours into their sleep episode and they just can't consolidate it. Yeah, I can certainly, I can certainly attest to that. Yeah, they're sleep fragments and if you pull in all night and don't even try to go to sleep, let's say that you just, you go out and you're promoting your event and you get in and you just think, I'm not sleeping tonight. What you'll experience over the next day is that how sleepy you are doesn't just build predictably over the course of that day. It waxes and wanes. Yeah, it comes in waves. Yeah, and around lunchtime, we have this so-called post-lunch slump.

And I think a lot of people have historically have thought that that's the result of eating a big heavy lunch. And that's not really the case. Well, there's an argument that this is due to an evolutionary, bi-phasic sleep tradition, is that right? Or there's some people who've claimed that? Yeah, there are some people that have claimed that. And you do see that in certain groups of people who haven't been affected by the effects

of industrialization yet. So if you look at the heads of hunter-huntered gatherers, for example, then what you see with them is that during the winter they have monofasic sleep. So all of their sleep is consolidated in one nocturnal boutique night. But during the summer they have a siesta. So the Spanish have got it right? Well, it's quite interesting in Spain is a lot warmer than somewhere like the UK and The Spanish have their cestars at lunchtime when it's hot they get out of the sun and they take advantage of that post lunch lump and

Meanwhile, it's not quite so hot here and we carry on about our working days. So Anyway, some people do seem to naturally have that pattern. I think if you're consistent in the habit of sleeping in that way, then it's a perfectly healthy way to go. But also, what I would say is that if you're not used that particular pattern, then during that lunchtime nap, you'll see a reduction in the pressure to sleep as you fall asleep. And what that means is that when you then try to fall asleep that evening, you might have a hard time nodding off. Yeah, I could definitely attest to

that as well. So to give you some, this is probably like patient zero for bad sleep for you, but I'll give you the example anyway. Very typically for me, if I've got a long day in the office followed by a trip to Manchester from Newcastle to run one of our events. I'll wake up at maybe, I'll try and push my waking time a little bit further back so I'll wake up at 9, I'll work and then I have to drive back from Manchester to Newcastle. I'll go to bed at 6am and then looking at my clock, I'll think to myself 24 hours from now, I'm going to want to be getting up because it'll be a Monday and I want to start my week on a good note. But that means that at 6 a.m. on Sunday morning, I need to fall asleep, wake up, fall asleep and wake up in the space of 24 hours. And, you know, as much as getting up and getting after it can be viewed as an admirable quality in a 21st century

corporate society where everyone's trying to be successful. It doesn't sound like that's the best thing for my health. No, it probably isn't. It's unavoidable in that particular scenario. So the question is, what do you do to cope with that sleep loss? And I think that what you try to focus on is getting some sleep and coping with the sleep loss during the way, but doing so in such a way that you don't interfere

with your ability to fall asleep the following evening. And another thing to consider is that you can try and preemptively prepare for those episode by banking sleep beforehand. So banking's an apt analogy here in that, let's say that you're trying to accumulate a certain amount of wealth in the coming week and each minute of sleep that you get represents one pound, okay? This week you try to bank as many pounds as possible by getting as many minutes of sleep as possible, knowing that next week you're not going to get that much sleep and subsequently next week you're going to be in debt. So that's how you try to prepare for it. So with Eucharist,

let's say that you've got a really good week this week and you can try to be consistent in your patterns knowing that next week you've got several events, that will help protect you in certain ways against the negative effects of the sleep loss that you will experience next week. That's crazy. So it is literally like a savings account. Well, it is, if you have a history of incomplete sleep. So let's just say that there's a fairy tale scenario which somebody's always

let perfectly. That person couldn't necessarily bank sleep because they don't have any sleep that from their previous life. However, that person doesn't exist as far as I can tell, at least. And for that reason, we probably all have something of a sleep that to pay off. And banking, although it might not be the case that it's technically possible, it is effective nonetheless in terms of what we're trying to achieve. So you could, would you aim to push maybe an extra half an hour or an extra hour for the couple of days preceding a late night? Yeah, I'd go about it in a few different ways and I think the one thing that's important

to recognise is that trying to force yourself to just go to bed earlier might be a fool Darren. The reason is that the way the drive that I mentioned before is at its highest just before you try to fall asleep and some sleep researchers refer to that as the forbidden zone for sleep. You just have a really hard time falling asleep at that particular time. That's lying awake staring at the ceiling, right? That's exactly right, yeah. So what you would do then is potentially try to shift your body's internal clock, your circadian system a bit earlier and you'd do that by exposing yourself to lots of bright light early in the day, perhaps doing some exercise early in the day too and then trying to reduce your nighttime light

exposure and starting your sleep routine a little bit earlier. Okay, so that's that's one way of intervening. Another thing is to address your caffeine and take. So while you're trying to bank sleep, trying to the tape of that will maybe go cold turkey and don't do it to me, Greg, please. That doesn't make sense because I know what you're killing me. Caffeine is an adenosine receptor antagonist. So one of the somerjans, which we spoke about earlier is adenosine, which is a breakdown product of ATP.

So as your brain expands energy during the day, it releases ATP from pre-synaptic neurons into the extracellular fluid that fades brain cells. Okay. And this ATP can act directly on sleep circuits in the brain to promote sleep, it can disenhibit, sorry, can inhibit weight promoting circuits too, or the ATP can be broken down to a denocene, and that can also have similar effects. And anyway, caffeine blocks the interaction of that adenosine with its receptive. It binds to the same receptor, right?

So basically, you've got all of this, that's exactly what it does. So you've got all this leap in a signal, but it's like somebody shouting, and there are no ears there to hear the person shouting. Okay. So avoid caffeine for those couple of days. Try and get yourself up and get moving. So you're almost artificially, artificially moving the daylight a little bit earlier in the day and then closing the sunset off a little bit earlier as well. Yeah, and then try and avoid waiting to alarm if possible during that time. And you can also

use banks to try to, sorry, you can also try to use maps to bank sleep during the day. If you're very short on sleep during that time when you're trying to bank sleep and using a map during the post-lunch lumb can be useful. Okay, well that's a really cool, a really cool little bit of advice there. So, I want to, we've touched on the effects of sleep and how important it is, I want to talk about enhancing your circadian system function and sleep, and then also how we can cope with sleep loss and then we're going to finish on some stuff to do with human OS.

So if you were to write a prescription for someone who wanted to have as good sleep as they could, have you got some principles that they should be sticking to? Yeah, many principles. And I think that it's worth starting with the daytime. So during the day you want to be physically active, and the reason that she comes back to a denocene, and the fact that as you burn more energy, you accumulate more adenocene, and then that helps you sleep more deeply at night. During the day you also want to expose yourself to lots of bright light and because the amount of energy

that your brain burns, you want to do cognitively demanding work. And also that can include other activities, so things like meditation are actually quite taxing and do consistently improve sleep, not just because of bad effect, but also because they probably have roles on things like stress regulation. I was sympathetic nervous system and stuff like that, right? That's right. Yeah. And then during the nighttime, I think that it's valuable for somebody who's not in a very

consistent pattern to set an alarm in anticipation of their bedtime. So let's say that your sleep routine takes you an hour, then you would set your alarm for an hour before bedtime. Yep. Regarding your bedroom itself, you want to make it stress-free. So keep it unclattered and use it for sleep and sex only. And then light exposure is really, really important. So during the day, get outside, lots and lots of bright light, and then probably around

two hours before you intend to go to bed, you want to start reducing your light exposure. And where possible, I would avoid artificial lighting, but I know that that's often not possible. So, what can you do in those circumstances? You can use apps on your devices, so things like Twilight for Android systems or Night Shift mode for iPhones. You can use F.lux on your laptop, which is online right now. You can also use things like blue blocking glasses. I don't personally use them. I just don't have the self-confidence. We're getting in a Ben Greenfield territory with blue blocking glasses, aren't we? Yeah, a little bit.

blue-blocking glasses, aren't we? Yeah, a little bit. So there's that too, and then as you fall asleep, are these blackout lines in your bedroom? Good curtains? Or just use a sleep mask? Is there any substance to photoreceptors in your skin being able to detect light. In short, I don't think so. There was a paper that was published in the Journal of Science in 1997, which received a lot of air time. This was the kind of journal art school that would get on the front page of the Washington Post because it was novel.

But it wasn't replicated. And what they did is they shone light on the back of somebody's knee, I think, and supposedly it was able to shift the timing of the circadian system. It hasn't been shown since. So as far as I'm aware, that's not the case. I know that there are these devices now that do things like shine bright lights in your ears.

Yeah, there's all kind of weird and wonderful sleep aids now, isn't there? Yeah, and not just for sleep, because light actually has a variety of other effects, the non-image formula effects, but effects that are either related to the circadian system, or they have effects on things like cognition. So bright light exposure during the daytime, routine evil, acutely boost someone's mental performance if they haven't been exposed to bright light before that. And that's why actually one of the ways the coat of the sleep lost that we're coming to is making sure we spend some time outside. So that is part of the picture, but these devices anyway, that shining lights in your ears.

Yeah, I'm not sure about them. I haven't looked close to the research. You don't have a pair? I don't have a pair, no. And I'm not aware of any sleep researchers, but seem particularly persuaded by their utility or put it that way. Okay, so I mean there's definitely going back to a couple of Ben Greenfield podcasts that I've heard in a few other anecdotal bits of evidence, people that go into hotel rooms and will put tape over microwave and air conditioning LEDs and stuff like that because even if they've got a they've got the sleep mask with them they're not happy with the darkness of the room.

Yeah, I think that a lot of that is overkill. Is that sweat in the small stuff? It's sweating the small stuff and the point actually is that these photo receptors in your eye that are involved in the regulation of your escadian system. Are quite sluggish. They keep a track record of your light exposure over the course of the day. They don't respond very acutely to it. So if you spend lots of time outside during the daytime,

you've had lots of bright light exposure, which is of a blue wave length in particular, then a little bit of light exposure at night from a microwave is a drop in the ocean. Yeah. It just won't shift your system. With that said, if you'd been in complete darkness for the previous 16 hours and then you went to the toilet and you switched the light on when you went to the toilet, then

that actually probably would shift the phase of your skating system. That's interesting. So you kind of become your sensitivity to light is increased based on what the most recent period of your day has been like. Strongly so. Yeah. That's crazy. I guess for people in certain professions, that's going to be a very important fact for them to take away. Yeah. It has strong implications for the shift work Yeah, it has strong implications for the shift work and for things like jet lag team because you have situations in which you want to go to shift work for instance, but just there for one evening to adapt to it. What did you, you referred that as a slam shift?

Yeah, and you've got all these different shift work schedules and in some instances, particularly in remote environments, people will want to go somewhere and they will always be on night shifts and in those rare circumstances, you want to fully adapt your circadian system and all you do then is you manipulate your environment such that you make that as easy as possible and you don't go outside. That's not most people. So the question in those situations is how do you go to work, maintain vigilance during that time, but not screw yourself up too much in the long term in the days to come?

With difficulty, it sounds. So we've got the black up lines, we've tried to expose ourselves to light during the day. We've had, I guess what you would, what's commonly referred to as a digital sunset, that two hour period before you're going to sleep, starting to reduce your light exposure, specifically to blue light, which is what's emitted from things like phones and iPads and TVs and laptops and stuff like that.

If you do have to use them, use a huing program, like phones and iPads and TVs and laptops and stuff like that. If you do have to use them, use a huing program which is night mode on an iPhone or similar application elsewhere. What about sleep posture and sleep temperature and the sleep environment that you're actually laid on? Have you looked into this much? Yeah, I've looked at temperature. Posterures interesting. And it's funny actually, I'm into being a guy for our podcast, Stuart McGill, who's arguably the world's foremost expert in spine biomechanics

in a few days' time. And I'm curious to hear his thoughts on that. I think that the best sleeping posture is likely highly dependent on the person. Probably the most comfortable one, right? Surprise, surprise. But anyway, some people find it very flexion intolerant if they bend over to tie their shoes or whatever if they sit at a desk all day, then they're spines really don't like being

in that position. So, creepy on their back over time, might not be wise. Other people are really extension intolerant. So if they arch back and look up at the ceiling, then they experience pain as a pattern that you see in people like gymnasts and for those people sleeping on their front is going to be unwise.

I think for most people, sleeping on the side is probably smart. And I generally find that people often benefit from having a pillow between their knees during sleep too. Something between their knees, just to keep them slightly jar. And I suspect that that's related to the spine. But I don't actually know what the mechanism is. It's just that many people seem to be more comfortable in that position.

But you and Mr McGill will hopefully find that out by the time that we've published this. I think yours will be up as well. So I'll make sure that I'll link that in the show notes for the listeners who want to go and do some further reading or further listening it should be. So how about temperature? Yeah, so temperature is interesting in that what we want to do is raise the temperature of the skin by a couple of degrees, shortly before sleep. And this is counterintuitive because during sleep, the temperature of your brain drops as you progress into deepest late stages of sleep.

So during deep sleep, it's at its lowest. And then during REM sleep, as the metabolic activity and brain rise, it goes up again. Is that just as a byproduct of the activity or is that? Yeah, it is partly a byproduct of the activity but things that you can do to facilitate that drop. Yeah. So help you fall asleep.

And by raising the temperature of your skin, you create this gradient between your core temperature, deep within you and the temperature of your brain and the temperature of your skin. And that helps you radiate heat out from your core temperature deep within you and the temperature of your brain and the temperature of your skin and that helps you radiate heat out from your core, improving your ability to drop the temperature of your core and your brain. So a simple way to achieve that is a hot shower, typically about 10 minutes at about 40 degrees C is about right within maybe an hour of when you go to bed. And then right within maybe an hour of when you go to bed. And then the parts of your body are also relevant too because your hands and your feet and probably your ears too are relatively unique in their structure. They have a very big surface area but not such a big volume and that makes them

very effective at transferring heat to the environment. The body's radiators, right? Yeah, exactly. So when you get out of the shower, you want to keep your feet warm. So stick some socks on. And that seems to consistently help people both fall asleep faster, stay asleep, and perhaps leave a little bit long with too, there's been some research published on that in the last few months. By keeping by keeping their socks on. Yeah, well in that instance there was actually using these special socks

that warm the feet slightly during sleep. Okay, so all of the all of the girlfriends that are listening who absolutely hate their boyfriends going to sleep in socks. They actually need to side-line their concerns about fashion and focus more on the fact that they're potentially getting a little bit of sleep. They need to stick their sleep masks on. Yes, and then they can't see the socks. Yes, we found the solution. So you've had the hot shower before you got a bed, and that is going to help you radiate heat away right from your core. Yeah, but then of course you don't want the surround

temperature to be too high and you want your bedding to let you continue to lose heat. So you need to be able to effectively transfer heat. And I know there are some companies out there that say that their sheets are better than other sheets are doing this. I'll just look into them. There are a couple of companies I'm familiar with, one of them is called Sheeks. And... Good name for a sheet company. Absolutely. And you can look into those. but anyway, the point is that you don't want your bedroom to be too warm. You also don't want it to be very cold, because, again, thinking about evolution,

if the environmental temperature was very hot or very cold, then that's a stressor to the body. And it's a signal that you don't wanna hang around, because otherwise you're gonna disrupt your ability to regulate your internal environment and for that reason the bedroom needs to be comfortable but cool. So you would err on the side of cooler than warmer? I would. Yeah and actually one thing that I love is using a fan because it serves two purposes. It keeps you cool. I would aim at your torso.

And also, it's a form of white noise. So, if you're in a relatively busy place, then it just drowns out all of the extraneous disturbances that could otherwise wake you up from sleep. Well, I'm glad that you've actually hit upon one habit that I've had for about seven years, which is a tiny little steel desk fan, which is next to my bed and I've kept with me since uni. And yeah, I couldn't attest to that more. It's nice to have the breeze and also you're totally right about the white noise in the background, especially if my sleep partner's been thrown out a little bit and I'm trying to then sleep through a morning where I've got housemates that might be moving around

and cars going up and down outside yet. It's definitely a double whammy on that front. So what else can we do to enhance our sleep or our circadian system function? Okay, so just sticking with the couple more things. One is related to diet, so it's both about caffeine really for the earlier. I would just say caffeine typically is metabolized relatively slowly. And for that reason, you don't want to consume too late in your day as an arbitrary cutoff. I would say try to not consume caffeine any later than about nine hours before you plan to fall asleep.

Oh wow, that is potentially very early for a lot of people, isn't it? Well, it's going to be hard for shift workers in particular. Yeah. But I think also the caffeine is something that when you go through the initial period of cutting a caffeine and taking sucks, many people have a lot of caffeine in it. But it passes. Yeah. And over time, as your sleep quality improves, the nice thing also is that you become more sensitive to caffeine again.

Yeah, so you need less. So you net a benefit on a number of different fronts. Yeah, exactly. And then when you do use it for those night shifts, in frequently, it has a very strong alerting effect on you. So you improve your sleep. You feel terrible for a couple of days when you're over the ham, it's all good. So anyway, I would say no more than about two milligrams of caffeine, a kilogram of body mass, if you're 80 kilos, then that's a bit more than a coffee. I know that's not an awful lot, but eat that by nine hours before bed. The half, the half life is, it tails off very slowly, doesn't it? Half life's about six hours, yeah.

And the half life for listeners is just the amount of time that it takes for the capping constation of your bud stream to reach half of the peak value of the experience after consuming the capping. So another thing is alcohol. And a lot of people use alcohol as a sedative and alcohol does reduce the amount of time that it takes people to fall asleep. It increases the amount of deep sleep that people get early in the night but then later in the evening as you'll live a clear the alcohol, your body

tries to frenetically catch up on the last rapid eye movement sleep and what tends to happen is you have these bizarre dreams and your sleep also fragments. So the quality of your sleep is reduced. I think this is something from the Adred with Matthew Walker's book, which is the important distinction between sleep and sedation when using substances to assist you. I think the same came up with regards to marijuana. Yeah, that's right. Many sleep drugs are hypnotics, so they put you in a more suggestive state and you can fall asleep more easily from that, but they don't necessarily produce physiological sleep. It's time under the curve that you're after, right?

Not just the planting the flag in the ground of I am no longer awake. Yeah, yeah, and it's a real issue and actually for people who struggle with sleep, one thing that I always say is that if you are in Somnia, the first port of cruel, is always CBT icon to behavioral therapy for in Somnomnia. If you're in the UK and you haven't insomnia, then I think that the NHS will subsidize an online CBT program. And what it is is a sleep education module teacher about sleep hygiene. It's very effective. Very, very effective. It's as it's effective online as it is in person too. So go that route before you touch any of the sleep drugs. I think sleep drugs occasionally have their place.

So let's say that Chris, you fly out to Hawaii and you're there for two days and by the time you go to bed that evening, it's the time at which you normally wake up back at home. And there's no way that you're going to fall asleep. Yeah. In that instance, I personally wouldn't mind taking a small amount of one of the other account sleep aids that you can take. Do you have a list of ones that are Dr. Greg Potter approved? I'm not going now. Do you have a list of ones which you use?

Or would you use? Well, this isn't advice. This is not advice, okay, to be incredibly clear to everyone who's listening. This is a hypothetical situation. This is not advice. And it's so probably actually not what I would take if I had access to sleep drugs because many of them are unavailable under subscription. Okay.

And the prescription, sorry. Yeah. So, you can get diphenhydramine over the counter, which is just the stuff that's in Nytol and that is what's called an inverse agonist that histamine H1 receptors in the brain. It just means that instead of just blocking the interaction of histamine with its receptor, histamine is a wake promoting neuromodulator. And instead of just blocking that interaction, it actually has the opposing effect. And thiphanyhydramine seems to help people fall asleep a little bit faster and they're sleep slightly longer. And it is available over the counter. The recommended dose is 50

milligrams in the research and you're only buying 25 milligrams tablets and they'll say start with that and increase your dose up to a maximum of 50 milligrams. So I think that can be useful. The problem with all these things is that when you target one particular neuromodulator in that way, you can quickly produce depends and which is to yeah, actually it's funny because there's a discordance Between people's perceptions of natural substances and medications So people will often resort to herbals, the paid thinking oh it's natural. It must be safe If they're targeting the same chemical pathways in the brain, then just because something is

from a plan, it doesn't mean that it's magically going to be okay and that it's going to have fewer negative consequences than it's synthetic counterparts. The potential for it to carry along with it some byproducts that might have unintended consequences as well is probably a little bit higher than something that's been synthesised purely for the purpose of being that particular pure compound. How well regulated is the supplement industry? Incredibly not. But the drug industry is also well debatably, but at least a little bit more, I think. So what about, I'm going to touch on it because I was recently in America, and this is, this seems so widespread.

I knew that I was gonna have a sit down with you, so I wanted to ask some people. Of a group of five men and ten women that I was sat around a table with, which is definitely not a representative sample, but ten out of the 15 of them all use melatonin every night and all of them reported using the tablets at least a couple of times per year. The tablets that they were referring to mostly were sublingual ones, which are dissolved under the tongue. I know that melatonin isn't available in the UK,

so this may be a supplement that a lot of people who are listening have never tried. Have you had a look at much research to do with melatonin? I guess it's external melatonin or? Yeah, I have, well, the final chapter of PhD was on this topic. Oh, well, you should know a little bit about it then. HD was on this topic. Oh, well, you should know a little bit about it then. Yeah, I really think that, but for any way, that's interesting. And what you're saying is that those people take it when they're at home on local time, but they think that it helps their sleep.

Exactly that. And multiple multiples of this group were combining that with wine and of that a smaller subsection, we're combining it with wine and weed. Yeah so so polypharmacy isn't smart and I don't recall this specific interactions for melatonin. I think that it competes with caffeine so so anyway melatonin is metabolized by the liver by some cytokarymenzyme. So I think people 50 and there are various other zenobiotics, so just foreign compounds, chemicals that are metabolized by that same enzyme. And what that means is that if you take it at the same time, something else,

then often the melatonin ends up being broken down far less efficiently than it would be, ways taken by itself. So you definitely shouldn't be drinking and melatonining. It's just a weird combination too. Well, being frank, you know, if that's the worst thing that the people sat around the table were taking from America, it's potentially not as bad as some of the stories that you're coming out. But it could be an awful lot worse. Actimellatonin as a sleeve age. I think that it's useful for helping people to synchronize their circadian systems when the circadian system is misaligned. So jet lag or adaptations, correct shift work, great, perfect use case scenario.

With very old people, sometimes they experience things like calcification of the pineal gland and in general their circadian rhythms become more disruptive, more disrupted at many levels. Are we talking 60 plus 70 plus? It's like anything else. If you look at the loss of skeletal muscle mass with age or decline in cardio-respiratory fitness, it's a gradual process. It's not like there's some sharp cutoff, but there could probably be with some disease dates, but that said. Okay.

As you see these dampening of circadian rhythms with age, I think that those people would sometimes benefit from melatonin. And there's a little bit of evidence to that end too. So for example, there's been work on people with insomnia who are also elderly taking a slow release form of malatone and called circadian at two milligrams and it seems to help those people maintain their sleep over the course of the evening. There's also some work on post-menopause women and the effects of taking malatone over the course of a year looking at bone mineral density in particular in body

composition, and actually melatonin seems to increase bone mineral density and reduce fat mass. At the end of the year, their weight was relatively stable, but the composition of that weight had improved. Oh, yeah, okay. So with those LDPs, I think that it can be useful, but for most of us who have relatively well functioning circadian systems, I don't see it as being very useful. I personally would use it at a five milligram dose

during jet lag, jet lag being when you travel from across at least three time zones. And I would take it about two hours before bed, typically. And you can use it preemptively too. So if you want to help you start preparing to adjust to a different time zone in advance to flying out there, then you can take it in the days before. So let's say that you want to fly three time zones to the east

and you'll need to wake up earlier and go to bed earlier. You can start taking malatown and progressively earlier in the days before. Yeah, start to align yourself with the time zone that you're moving to before you get there. Yeah, so I think that's useful. Okay, and then shift, shift work potentially as well. Chronic shift work, yes, to help stabilize their patterns, because it's just so easy for

people that consistently work night shifts to finish up and then start driving home and the sun's coming up, and it's coming up at exactly the wrong time. Regular when I'm driving back from Manchester if it's during the summer, that I'll need to put my sunglasses on because I'm driving down in the Sun setting and then around about 3 30 or 4 am I'll need to put my sunglasses back on because the Sun rises hitting me in the face since I'm trying to get home. Yeah, well it's smart. That's exactly what you should be doing with sunglasses on. Yeah, well, I'm making sure that you stay awake and of course, Chris, shouldn't be driving drowsy. I'm not sure. I'm, yeah, but I also can't have, you've told me that I

can't have caffeine up to, ideally up to nine hours before bed in the half life, six hours, but my usual plan of necking a monster three hours before I get home, which is the exact time that the journey takes me is, I'm kind of fighting it's a movable object and unstoppable force here, isn't it? I'm kind of fighting it's the immovable object unknown stoppable force here, isn't it? So what I like is before we just return to melatonin, you can take a very brief nap and actually to have the biggest short-term effect on your alertness, all you need is a 10-minute nap. If you take a longer nap then you start to progress into deeper stages of sleep and

the issue with that is that as you go into deep sleep, you have this sleep inertia afterwards, so you wake up and you feel drowsy. You have this later boost in alertness, which is ultimately of a greater magnitude than the shortening of the nap, but if you just want a brief nap and something that's going to give you the kind of increase in alertness that you get from the caffeine,

10 minutes by the side of the road, if you stop off, will give you much the same effect and it won't impair your ability to fall asleep later either. That's fantastic. So I'll know that my business partner, Darren, he'll be listening. He absolutely loves, I think, whether he services or scotch corner of his two favourite spots on the A1, so he's got it right. I think he takes one of his two favorite spots on the A1. So, you know, he's got it right by, I think he takes one of his socks off and drapes it across his eyes if it's too bright, I'd say. I'm not sure how scientifically accurate using a sock for a face mask is, but it needs most, I suppose. So, going back to the melatonin use, do you think then that a lot of the dependence on this is just that that it's a psychological dependence rather than a physiological one? Well, there's

lots of interesting preclinical by which I mean studies on animals research that's been done showing all of these positive effects of melatonin on various outcomes. There's actually a journal called the Journal of Penial Research and everything in that journal, more or less, is about melatonin. And melatonin does all sorts of cool things to other animals. You get them a fattling diet, melatonin reduces the fattling effects of that diet. You induce diabetes temporarily, Melatonin protects against the development of diabetes or helps reverse it. So, with that in mind, I think a lot of people have looked

at some of this early research and thought, oh well, melatonin seems innocuous. So, I think it's a panacea. Yeah, but I suppose what I will say is that it is remarkably safe, melatonin. And whereas the other sleep aids that people take will lead to that kind of tolerance and withdrawal effect that I mentioned,

melatonin's unusual, so it doesn't really seem to have that effect. So if you, for example, as a guy take testosterone, then there's this negative feedback cycle. You have this exogenous or, from outside the body testosterone that's floating around your bloodstream, and your body will naturally shut down its own production to help you maintain relatively normal levels within your bloodstream. But with melatonin, that's not really the case. If you take melatonin from the outside and actually a common melatonin dose, let's say two milligrams, that will produce melatonin levels in your blood, which is orders of magnitude higher than the natural levels that you would produce.

And actually, there are some people who have absolutely no detectable melatonin in their blood during the day at any time and they sleep okay. So, melatonin, whereas people think about it as a sleep hormone, isn't really a sleep hormone. If you take in this big dose, then it does reduce core body temperature and help people fall asleep a little bit faster. And you do sometimes see that effect in healthy people, but apart from that, the effect on sleep seems to be quite negligible. And there's also some emerging evidence now that melatonin does play roles in metabolism as you would expect because it's carrying this nighttime

signal throughout the body. And in people with a particular variant of the melatonin receptor, having too much melatonin floating around at the wrong times is not a good thing because for example it will impair their ability to dispose of glucose in their bloodstreams effectively. So with all of that said, healthy young person taking melatonin, they might fall asleep a little bit faster, that unlikely to do themselves any harm in the long term. If they have this melatonin receptor variant, then it might be contraindicated. But save your money and spend it on something more fun or more valuable to your health. Yeah, so save the money on that tub of melatonin

or something similar and buy a pair of blackout blinds. Much smarter. Okay, just because we're on to draw a line into substances, compounds like 5HTP, I know that they're very, very popular. Have you had a look at anything to do with that? I have, yeah, but not this year actually. I did until about December last year have a relatively close look at the literature on

all sleep supplements. So some of the herbs that are out there, various amino acids, so 5HGP, trip to fan, glycine, they're all sorts of ones that people have looked at. What does the research say about them? Triptophan might be the most interesting to me, other than glycine, we'll come back to glycine. So, Triptophan, there was a lot of research on in the 1980s also, and it's a precursor to melatonin ultimately, but via serotonin.

And it's funny because people once thought that serotonin was a sleep hormone, and it's not, it's actually the exact opposite. It depends on the path of the brain that you're looking at, but in general. Wait for this hormone. Yeah, serotonin is involved in weightfulness this. So taking tryptophan the view towards increasing melatonin levels doesn't make that much sense if it needs to go via serotonin. But anyway, some of those early search studies

on tryptophan did show some effects on sleep. I don't recall specifics of tomayello. I think we might have fallen asleep slightly faster. And they were some well-done studies, two people using polysumnography, I don't recall specifics of Tom Meadow, I think people might have fallen asleep slightly faster and they they were there were some well done studies to people using polysumnography which is where you measure things like the electrical activity in someone's brain and their eye movements and that gives you the most objective measure of different sleep stage that people cycle through. So, trip to fan is interesting but there hasn't been the kind of

Rigger in the research that I would want to see before I would recommend it glycine is interesting for various reasons not just related to sleep and I think the glycines relatively nice for only things that you can take and it's unlikely to hurt the glycines relatively ignites, one of these things that you can take, and it's unlikely to hurt you. Glycine might help with sleep by binding to receptors in the master clock in the brain, and by doing so it actually increases peripheral vasodilation. So blood flow to your extremities, and by doing so, it increases that radiator effect that we spoke about. Core temperature manipulation again.

Yeah, it facilitates that drop. And there have been a couple of studies showing that taking glycine helps people fall asleep faster and sleep slightly longer. Again, the quality of that research isn't that high, but if you look at the effects of glycine and other things that's being studied for things like life, span extension and also joint integrity, then I wouldn't really hesitate to recommend. The other thing is that the amino acid composition and most people's diets now is probably quite different from our distant ancestors in the once eight nose to tail. People nowadays don't really,

and the majority of meat people eat is muscle meat. And for that reason, they miss out on the types of, or the same proportions of amino acids that they once would have got in their diets eating in a more natural way. And glycine is one of those amino acids that they may be skin-pun. Interesting. I wouldn't hesitate to try glylyce. It also tastes like sugar and

you can take three grams of that about an hour before bedtime and see if it helps. It's very cheap too. I'd recommend that before taking melatonin. Fantastic. Okay. Well, we've got some nice bits to follow there. So I want to ask, you've mentioned this word earlier on. I've got no idea what it means. What's corononutrition? Yeah. So corononutrition is the study of the interactions between your diet and your body's clock.

So how, for example, does when you eat, influence the timing of the various clocks in your circadian system? Or what are the implications of when your circadian system is best prepared for various activities on when you should eat? It's that reciprocal relationship. I understand. So, we're going to go on to ways to enhance circadian system function and chronic nutrition ties in quite nicely here. How highly would you place chronic nutrition on the list of ways to enhance your circadian

system function? For most people, I would say that it's probably quite important. It's a very nascent area of study. There aren't many researchers that have spent many years looking at it. But so far, the evidence is very interesting. And I don't think that many people think about it. And for that reason, it might be a low hanging fruit. Everybody historically is focused on what they should be eating

and not when they should eat. And being more consistent in eating patterns and restricting them to your biological daytime. So not the time of day at which your body is saying, I should be sleeping now. Is smart for many reasons. And there are many different directions that we could go with this.

One more thing that I'll mention is that whereas the light dark cycle is the main time queue for the master clock in your brain, your diet seems to be the main time queue for many peripheral clocks by which I'd just mean all of those clocks outside the master clock in your body. So that actually means other clocks in your brain too, but the clock in your liver and your guts and your skeleton muscles and so on,

and your fat tissue. So many people they eat in very haphazard ways. One day they wake up in the morning and they have breakfast at 6am and they have dinner at 10pm. The next day they skip breakfast, they're the first meal at 1pm in the morning and they have breakfast at 6am and they have dinner at 10pm. The next day they skip breakfast, they're the first meal at 1pm in the afternoon and then they have their dinner at 6pm. And that type of inconsistency seems to be a bad thing. If you take people on the very rigorous conditions and in one, they have a consistent number of meals each day. And in another condition, they take exactly the same food and they distribute it into a varying

number of meals. Then at the end of those two periods, the people who've had the varying number of meals were tender, burn fewer calories in response to eating, their blood sugar regulation will be worse, and their blood that could profile as we worse too. That's interesting. In healthy young women. So consistency is important. Another consideration is the duration of the caloric period. And I say caloric period because I can talk about eating period. However, many people now will have some sort of concoction from Starbucks that has 800 calories. And they might as well be drinking a blended lasagna or something because actually it has the same

things in it. You have large quantities of fat in it and calories and so on. I think it's more useful actually to think about a caloric period. When am I consuming calorie containing items, and even more useful to think about when are my consuming items that aren't just water and trying to make that consistent? I was going to say so you'd included in cal-o things that aren't just what would be coffee, for instance. Yeah, and I would throw things like coffee and tea in there, even if it was coffee without milk and sugar because coffee contains caffeine. And we haven't really spoken about this, but caffeine per se does seem to influence the

skating system too, at least in cells and probably in humans too. It's been showing that if people consume caffeine later night and they delay their melatonin synthesis onset in the evening in constant conditions. Okay. So anyway, that period probably is relevant to you for a lot of people. I think consistency might be the most important thing, but people now are looking at the so-called time restricted eating studies. 16, 8, so like 20, 24s and stuff like that with intermittent fasting, right?

Yeah, exactly. And there's been, there are a few people who are very vocal about its benefits, but actually if you look at the entire body of literature on the subject, there just aren't many studies points at the moment. I mean, anyone who's pavade read it recently will know that between intermittent fasting and no fat, you have like the two most militant dogmatic cultures, subcultures of people who swear that they get superhuman benefits from eating four hours out of 20 or eating after 24 hours of fasting or not touching the penis. I don't know. I wonder how many people are doing intermittent fasting and no fat together. That must be a pretty miserable existence. But yeah, it's, um, both of them seem to be from a similar kind of camp. Yeah, and I, I think that it, it probably is useful in some circumstances. So,

what does the evidence show so far? It shows that if you take people and in one condition, they're allowed to eat when they want, and in another condition, they restrict their eating period. Typically, what happens is the people who restrict the eating period or the cloric period will consume fewer calories, but they'll also expend less energy over the day. So they specifically tend to engage in non-exercise activity pharmacosis, which is just fidgeting,

and probably take a few fewer steps each day too. And the net effect of that is that they burn less energy, they consume less energy, and therefore remain in energy balance as they did in the other condition in which they just eat when they want to eat. So that doesn't seem to be beneficial. And there are a couple of very nice studies that are showing that too coming out of the inverted bath,

and also some work from the US too. So body weight seems to be relatively unaffected. Then there's blood sugar regulation. If anything, skipping breakfast specifically, there's one way to shorten the eating period. Seems to impair your ability to regulate your blood sugar later in the day. Your blood sugar levels in response to consuming meals are more variable. And that variability is somewhat predictive of the development of metabolic disease a day. Your blood sugar levels in response to consuming meals are more variable, and that

variability is somewhat predictive of the development of metabolic disease, and subsequently like diabetes. Okay. So that's not a beneficial effect. And then almost everything else that's been studied, it doesn't really seem to be having a strong effect on. If anything, it seems to increase inflammatory responses to feeding, which also probably isn't a beneficial effect. Am I saying that it's never going to be useful? Absolutely not. But I think that these kind of compressed eating periods aren't necessary for a lot of people. I think that at the moment there are too many people jumping on the bandmagon and saying that this is enormously important when so far the science doesn't really show that.

It does show that in rodents. If you look at mice for example, then it is very protective against metabolic disease development. It's a long-gevity, right? It's a 30% increase around that number in terms of longevity. Yeah, all sorts of things. And one of the really difficult things that people are only just starting to tease apart is the effect of restricted, chloric periods as the stints from the effects of energy restriction

because often the two have gone hand in hand historically. Yeah, is it that you're eating less food or is it that you're eating within this special window? Yeah, and only very recently have researchers developed the types of methods that they need to answer those questions even in laboratory animals. So it's going to be very exciting to see what the results of some of those studies are. But anyway, these types of restricted cleric periods are really, really beneficial in other animals. So far, the effects on humans don't really seem to be particularly remarkable as far as I'm concerned from what I've seen.

But I do think that they will prove to be very valuable for certain people in certain circumstances. Is that in the same way that keto can be useful for people who suffer from epilepsy, for instance? Yeah, that's a very good analogy. I think probably actually people with things like gastrointestinal disorders will benefit from restricted eating periods because you just give the whole track to break for a consistent period of time each day. So that's one example of a use case which to me makes perfect sense. So there's that. And then there are also certain circumstances in which people are unavoidably inactive and if they're just sat at the desk all day and they restrict their caloric period and they end up eating less

because they restricted it and what they have absolutely no bearing on their activity regardless, then that might be useful too. So I think that my key takeaways would be that you don't want to eat too late at night or as soon as you wake up in the morning, especially if you wake up to an alarm. You want to wait until shortly after you would naturally be awake before you start consuming anything other than water in my opinion. And then also consuming late at night. So let's say within five is going to give you an average of cutoff within two hours of when you plan to go to bed. There's probably a rise because one of the things

that you see in response to calorie ingestion is that your body has to use energy to break down all of those nutrients. So you call temperature rises and that's going to negatively affect the drop in brain temperature that's necessary to helping you initiate sleep. It's there's so many nebulous little elements that are contributing to sleep and the quality of sleep and then you

know earlier in the discussion we we went through just how important it is and why it's important to get good sleep. I think it would be quite easy for someone who's listening to hear any of these individual, individual points in isolation and think, well, you know, like, do I really need to avoid eating, do I really need to do the hot shot shot, I really need to have the cool room and the fan, sun and so forth. But you think it's one thing that you're going to do absolutely every day. Habit setting to clean your teeth was done when you're a child and now you don't think twice about it. But if I told you to do it, if I told you that you had to spend two minutes, three times a day sticking something in your mouth and you'd never done it before in your life, you'd think, oh, well, that's probably a little bit of a pain in the ass. And, you know, to look at optimizing and drilling down

to its constituent parts, a process which all of us need to do, and which we've already identified is really crucial for short-term performance and health, and then long-term health and longevity. You know, I think the can't really be too much weight applied to people trying to do this. Especially with Matthew Walker's book, Why We Sleep, it's been pretty widespread. Can you feel a change in the tide of the interest in sleep and the appreciation for how important it is in the wider populace?

Yeah, there's been an enormous shift actually. And I'm grateful in a way because it's coincided with my PhD. I was going to say, do you feel like you're riding the crest of a wave at the moment? Yeah, I think so. And I don't want to sound, this could easily come across the wrong way. But anyway, I had a paper published in the second year of my PhD, and the paper is entirely unremarkable. It's an OK publication. There was nothing revolutionary about it whatsoever. Basically found that people who sleep less, people who report sleeping

less in the UK are, on average, heavier, have bigger waistlines and tend to have lower levels of HCL cholesterol, which is just a type of cholesterol that's involved in removing fatty deposits in your blood vessels from where they shouldn't be. And my supervisor decided to send out a press release on the back of that paper. And people went absolutely nuts for it. It was very, very strange. I was interviewed by the BBC World Service. It was in the New York Times. It was in USA today. Were you shocked? I had no idea what was going on. So that's, idea of what was going on. So that's, I'm not saying that to make it out as if I did something great because I fully recognised that I absolutely didn't. It was just fascinating to behold.

It's a marker for how interested people are becoming in sleep, right? Yeah, it's a perfect marker for it. But what a fantastic development because we have spoke to people like Matt Walker who is a fantastic scientist. There are very few people in the world if anybody in the world who knows more about sleep and memory specifically than Matt Walker, but he's also a great communicator. So the nice thing is that we have a handful of people like him who are spreading the good word about sleep and they're actually generating a lot of momentum and getting in front spreading the good word about the, and they're actually generating a lot of momentum and getting in front of the people that they want to be

in front of and starting to instigate some change by raising awareness and over time more progressive employers and so on are starting to think more about this, okay, if our people are sleeping better, then they're gonna spend less time absent, they're gonna be more productive when they're at work and so on. So one of the things that we can do in the workplace to make it more conducive to having people meet their sleep needs.

So the tide is definitely there at the moment. And what's interesting is that, whereas with diet, things are repackaged every few years into another fad, and the fad itself, more or less, delivers the same information in a new way. Like calorie deficit. So, calorie calories. Eating more vegetables for most people is probably smart. Protein helps keep you full and don't eat pizza.

If James Smith PT is listening, he'll be shouting at the mic at the moment because he is the number one proponent of Don't Buy Into Fads. You just need a calorie fucking deficit mate. you just need a calorie fucking deficit mate. That's... You've had famous instances of that haven't you? Like, off the back of what was that film with the famous journalist who went to the name of Donald's for a period of time? Was it a fast-fungation? Super size me.

Super size me. So, he was in really bad shape after that. It was fucked. And then there was a smaller documentary by small I mean in terms of the amount of attention that it generated in response to that in which somebody consumed fast food for a similar period of time, but ensure that they were in an energy deficit and almost all of the health outcomes that they tracked and proved over that period of time.

So calories are important and there are these fundamental things. But what I was getting at is that with diet you have all these different factions of people at the moment, everybody is absolutely bonkers for keyed genetic diets, which completely battles me on a personal level, but at the same time, I do understand it. And that will pass, and there'll be another one that pops up. Well, I mean, to interject there, the listeners will know how much I adore Jordan Peterson, and as a thinker, he's fantastic, but as a dietician,

I would not, personally, I would not take his advice. He was sat on Joe Rogan saying last a couple of weeks ago that he'd started the carnivore diet where he eats juice. He'd cut greens out from a ketogenic diet and was never really doing the fat. He eats steak and salt and that's it. And he was saying to Joe, he was like, I couldn't bloody believe it, you know?

I lost 10 pounds in the first month. And then, you know, I lost 10 pounds in the first month, and then the second month, I lost 10 pounds, and that continued every month for five months. I'm the same weight I was when I was in college, I can't bloody believe it. Like, do you understand how many calories you're having per day, Jordan? Your my fitness pals say is probably 1500 calories, or less. Like, where did you think was going to happen? Your body's starving. Now, I know that your daughter's autoimmune disease has been cured absolutely fantastic and

yourself, depression, mood regulation, all of those things, but you can't attribute the weight loss to some magic manipulation of what you're putting in your mouth. It's the fact that you're not eating very much. He said, oh, my, he literally says two minutes after that. Hey, you know, my hunger's dropped by 70%, at least, I'm never hungry. I'm like, well, are you fucking surprised? Your body's starving. I actually watched that.

Just as an aside, I'm not sure if that was a Canadian accent or a knife. That's me trying to do Canadian, okay? That's my best Jordan Peterson. No, but I think there's a very accurate recollection. In fairness to Jordan, he did say, I am not a dietician and not giving people advice, but the problem is that if it's true in his book is the best-selling book in the world in the last 12 months, then he has this enormous peep, the enormous number of people listening to him, and people latch onto that.

And all of a sudden we're going to have the Jordan Peterson beef diet, beef and so on. And that's probably not smart. But anyway, to go back to the original point, Steve isn't something that you can re-package in that way. Yes. So it doesn't, I don't think it has the fad potential. I think that various steep technologies do. And sometimes the fads themselves aren't a bad potential. I think that various sleep technologies do. And sometimes the

fads themselves aren't a bad thing. Insofar as they continue to engage people with the behaviors that they need to carry out on a regular basis to be healthy. So I don't care if somebody uses a new toy in order to accomplish that. If it keeps them doing what they need to be doing, and that's great. If the focus is on, so if the blue blocking glasses mean that you're thinking about your sleep

as a byproduct, then cool. Exactly. If you're taking melatonin an hour before bedtime, and that's the start of your pre-bedroom team, and it's a signal to ingrain that habit and get in the right mindset for sleep, something we didn't touch on earlier is the mindset and just making sure that you have a clear mental conscious before sleep. That's great. And it's as long as that particular behaviour isn't counted productive. I'm all

for it really. It's a very holistic view of the subject area and of the market or industry if you want to call it as a whole from yourself. I can imagine that for some people in other industries this level of attention would actually be quite threatening. Oh well here we go, the charlatans are rubbing their hands together, ready to capitalize on this and start spreading disinformation. But as you say, because it's quite specialist field, heavily researched to one degree or another, although perhaps not entirely understood yet, that there seems to be less opportunity for this disinformation to be pushed. Yeah, I completely agree.

And anyway, I just hope that that particular engagement with the importance of sleep is something that's sustained over time. Fantastic. So I want to finish on two things. We're going to go on to the human OS in a moment, but the cognitive function and how your sleep affects that. Are there any final ways that you think that people can improve, if they've had a bad night's sleep,

what can they do the next day to just kind of get themselves moving a little bit? Okay, so I'm just gonna park that for one second and just say first, if it's possible, try to bank sleep before, if you know that you're gonna go through one of those days. Yep, another thing is that you should plan the menial tasks for these days, you're going to go through one of those days. Another thing is that you should plan the manual tasks for these days.

You're not going to beat your best. You shouldn't be sending important messages that have long-term consequences. Also, on these days, you don't want to do things that are going to impair your ability to get good sleep that night. So with all of that said, what can you do on those days? One thing is release the temperature. So slightly uncomfortable temperatures do boost vigilance, and they're

not going to impair your sleep at all. So if, for example, you can expose yourself to slightly colder temperatures, then you're going to raise your alertness in the short term. So that can be things like cold showers, but also if you're in an air-conditioned room, then maybe just adjusting the settings will help you maintain alertness during that period of time. Another thing is light exposure, so I mentioned the effects of bright light on cognition.

So you spend lots of time outdoors, that's going to be really important if you're up during daylight. Naps are something that we touched on and I think that they can be really useful. So why would you use a NAP? One reason would be improving your ability to form new memories and they improve various types of memory formation. So you have these procedural memories which are memories of how to carry out specific tasks, how to write a byte, how to hit a cricket ball, whatever it might be. You have the clarity of memories,

which are memories of facts. So I know that 8 plus 6 is 14, whatever it might be. Another purpose would be to temporarily boost your energy. So we spoke about how that 10 minute nap seems to have the greatest short-term effect on your energy levels slightly longer naps will have this sleep inertia consequence Immediately afterwards, but that will dissipate and then later they'll have stronger alerting effects Is there a is there a period of sleep inertia that? How long is that is it half an hour? Is it a couple of hours?

It's it's probably once you pass about 20 minutes or so, as soon as you enter into deep sleep, especially if you wake up from deep sleep, you're going to experience that sleep inertia. Yeah. So these sleep cycles, they tend to last about 90 minutes on average. So let's say that you had a 90 minute sleep cycle and then you woke up at the end of a period of in a sleep cycle and then you woke up at the end of a period of REM sleep in which you're dreaming. You probably actually feel okay. After this, but half hour nap when you woke up from one of the deepest age of sleep, then you'd experience that sleep inertia. Another function of NAPS is your ability to learn new things. So while you're awake,

your brain is forming all of these new synaptic connections and during sleep those are scaled down. So your brain figures out what do I need to hold on to? What's useful information for my long-term viability and what's not? And it retains the useful information and then it frees up new space by pruning away the connections that it doesn't think are important. So it will actually have very valuable effects. If for example, you're a bit short on sleep and you're studying hard for exams, just

taking that nap will both enhance your memory consolidation, but then also free up some space for you to learn new things too. It's also boost your immune function temporarily. And after sleep deprivation, for example, having both mock turn on sleep and a nap has an additive boost on a immune function. And then that's what buffer against the effects of losing sleep. So if you've lost some sleep. So what you're saying is that sleep's the panacea, the nap, the daily nap is the cure.

Well, I'm very sure on sleep, then actually just having a brief nap, however brief it is, is often going to be really, really useful. I mean, who'd have thought that if you if you're short on sleep, that the solution was to try and get some sleep? Yeah, I know. So I want to move on to human OS. Can you try and explain for the listeners what that is? Yeah, so we live in an age when we have different apps for everything related to our health. So you have a meditation app. You have a Fitbit on which you track your physical activity and your sleep.

And then maybe you go to various websites for information about how to live a more healthy lifestyle. What we try to do at Human OS is consolidate all of that in one place. So Dan's created Dan the CEO has created this loop model to sustain health behaviors, and the fundamental premise is that we educate people about what they need to do to be healthy. We let them track their behaviors to see if they're carrying out those behaviors. And then we also let them see if those behaviors are moving in the needle in the right direction. So it's a platform that you can sign up for and it will integrate with

various wearable devices, so things like Fitbits and MFITs and so on. We create online courses about things like diet and sleep. We have a podcast and a blog, to which I regularly contribute. And we have various plans in the future also to pump out protocols to help people navigate certain common situations that we all face on a regular basis.

So for example, I'm sure to leave today. I don't want to mess with what should I do. What's everything that I can do in order for me to be at my best in these circumstances without having a long term negative effect on my health? So it's the SOS button for a couple of situations that might happen? Yeah, yeah exactly. And we also try to bridge the gap between the information and the actual practice. So for example, we have courses on cooking and there are daily workouts.

So it's just somewhere you can check in each day to keep you engaged with the behaviors which ultimately are important for your health and to try and make it sustainable and fun. That's awesome. Well, I'm really excited to get stuck into the site, I signed up earlier on. I know that very kindly, Eric from Human OS HQ has set up a discount code. So for anyone who's listening who wants to check the site out, you can sign up for free for the basic version, or if you use the code modern wisdom,

you can get one month for a dollar at humanos.me. Is that correct? Perfect. Fantastic. So Greg, would you be able to tell the listeners where they can find you online, please? Yeah, I'm just going to point towards everything Humano S related. So, Humano S.Me, you can find Humano S.Me on Facebook and Ginny, who is another of my colleagues, they're regularly

puts things up there. Just views and news and brief synopsis of interesting studies that have been published recently. There's Schumno S, at Schumno S, underscore me on Twitter and I'd say check out the podcast and the blog. So the podcast is something that covers sleeping great depth but also a variety of other topics, particularly focusing on various advances in technologies that could be various promising and countering things like aging in the future and technologies that consumers can use to improve their engagement with these important behaviors too. And then also have a look at the blog. So that is every way you can find you in no S online. Fantastic. Well, Greg, I really appreciate your time. There's been an awful lot to learn

there and I thought, I genuinely thought coming in that I was going to hear just a repackaged information that I either knew anecdotally or I knew from reading online or from Matthew Walker's book, but it seems like the subject area is so complex and there's so much for people to understand that it, I really like what you say about people having to engage with it as a cared about metric of their health, a cared about habit that they have to do, as opposed to just that thing that happens at night. And hopefully we've helped impress on people today just how important it is and some of the tactics they can do to help.

Sure, and view them as tactics too. So I don't want people to feel overwhelmed by the number of different things that we've spoken about. I would just say, okay, this is your lifestyle at the moment. You think that that particular behavior is something that you can easily try. Give it a go. You have to try anything else. And actually having that type of attitude where you just see yourself as a self-experiment. And you try all these different things that you think, okay, that might help me. Probably won't hurt me. I'm just going to try it for a period of time and see how I get on is a really healthy

attitude to making sure that you can just keep doing what you need to do in the long time. I agree. Greg, thank you so much for your time. Good luck with the human OS.me development. I will be keeping my eyes peeled very closely as you release more of your content. Thanks a million Chris.

Cheers mate. Bye bye. you