Feel Better, Live More with Dr Rangan Chatterjee - #70 Why Sleep is the Most Important Pillar of Health with Professor Matthew Walker

Episode Date: July 10, 2019

This interview originally aired 12 months ago as a 2 part conversation, which have proved to be two of the most popular episodes that I have released so far. Many listeners have asked me to re-release them as one single conversation so that they can listen from start to finish without interruption, so here it is! Sleep is one of the most undervalued components of our health, yet neglecting it can have devastating consequences. In this episode, I talk to world-leading sleep researcher, author of the international best-selling book ‘Why We Sleep’ and Professor of Neuroscience and Psychology, Matthew Walker. We discuss everything you ever needed to know about sleep. Matthew shares some brilliant tips to combat jet lag, explains how sleep can enhance athletic performance and decrease risk of injury and reveals just how much caffeine consumption can impact sleep. We explore the reasons behind the current global sleep-loss epidemic and how sleep deprivation can affect every aspect of our health – from our blood sugar levels and our risk of heart attack to our mental health. Finally, we discuss alcohol’s impact on sleep and the staggering financial costs associated with lost sleep. Matthew also shares what he has changed in his own life since starting his research. This is an invaluable conversation – I hope you enjoy it! Please note: Matthew has agreed to do a follow-up podcast to answer any questions you may still have about sleep. Listen and let me know which questions you would like me to put to Matthew via my closed Facebook group (Dr Chatterjee 4 Pillar Community Tribe), where you can also discuss other podcast episodes and any lifestyle changes that you are trying to make. Show notes available at drchatterjee.com/70 Follow me on instagram.com/drchatterjee/ Follow me on facebook.com/DrChatterjee/ Follow me on twitter.com/drchatterjeeuk DISCLAIMER: The content in the podcast and on this webpage is not intended to constitute or be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or other qualified health care provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard on the podcast or on my website. Hosted on Acast. See acast.com/privacy for more information.

If you look across epidemiological studies, millions of individuals in these studies, a very simple truth comes out, which is that the shorter your sleep, the shorter your life. That short sleep predicts all-cause mortality. Wow. And so, you know, I think… I think we just need to stop and just let that sink in for a minute. Depriving ourselves from sleep will shorten our life. Yeah. Yeah, I mean, that's the powerful data that, you know, the global sleep loss epidemic that is underway right now, which I believe is probably one of the greatest public health challenges that we now face in the 21st century.

It is a slow form of self euthanasia. television presenter and author of the best-selling books, The Stress Solution and The Four Pillar Plan. I believe that all of us have the ability to feel better than we currently do, but getting healthy has become far too complicated. With this podcast, I aim to simplify it. I'm going to be having conversations with some of the most interesting and exciting people, both within as well as outside the health space to hopefully inspire you as well as empower you with simple tips that you can put into practice immediately to transform the way that you feel. I believe that when we are healthier, we are happier because when we feel better, we live more. Hello and welcome to episode 70 of my Feel Better Live More podcast. My name is Rangan Chatterjee

and I am your host. Today's podcast is all about sleep. I've decided to re-release two of my most popular episodes so far as one complete conversation. Over 12 months ago, I sat down with Professor Matthew Walker, author of the international bestseller, Why We Sleep. We had so much to talk about that I ended up splitting up the conversation into two separate episodes. Many of you have asked me to re-release our conversation as one complete episode so that you can listen without interruption from start to finish. If you have already heard this conversation, I hope that this re-release will encourage some of you to revisit it and remind yourself of just how important our

sleep health really is. In addition, since the initial episode came out, this podcast has grown exponentially and has picked up tens of thousands of new listeners who may well have not heard the chat first time round. I do believe it is one of the most important ones that I've ever had on the podcast because sleep is absolutely essential to optimal health, yet as a society, we have chronically undervalued it. One of the other reasons why I have re-released this conversation is because Matthew has kindly agreed to do a follow-up podcast with me on Feel Better Live More to answer any further questions that you may still have about sleep that we have not covered in this incredibly detailed conversation. So do take a listen,

make some notes, and then let me know what questions you would like me to put to Matthew for our next podcast together. The best place to let me know your questions is in a brand new closed Facebook group that I have set up only this week. Many of you have told me that you would love to be part of a community where you can discuss each week's podcast topics with other like-minded listeners. It can be hard to really get that community support on the odd social media posts. Now, I've done a bit of research and it's quite clear that closed Facebook groups are a brilliant way to do this. All you need to do is head over to Facebook and search for the name Dr. Chatterjee 4 Pillar Community Tribe and you will find my brand new Facebook group. As you know, I'm a huge believer

in the power of community. This is something that we've talked about on so many occasions on this podcast. That is why I have decided to start this Facebook group so that we can create our very own supportive community with like-minded individuals. Each week you can discuss the topics from the podcast with other listeners. You can discuss lifestyle changes that you are trying to make and utilize the power of the community to help keep you motivated with your changes. I will be jumping on there now and again and will try and do the occasional live Q&A. Lifestyle change is really hard to do in isolation so my hope is that this group will provide a safe and supportive space to help get inspiration and to encourage others. So on to today's conversation, just how

important is sleep? Is sleep the most important pillar of health? Is sleep more important than diet and exercise? Is sleep your very own superpower? Well, these are some of the questions that today's podcast hopes to address. We talk about jet lag, explain how sleep can enhance athletic performance and decrease your risk of injury, and reveal just how much caffeine consumption can impact sleep. We also explore the reasons behind the current global sleep loss epidemic and the effect that this is having on our health. We discuss how sleep deprivation can affect our blood sugar levels, increase our risk of heart attacks and impact our mental health. We also talk about alcohol's impact on sleep and the staggering financial costs associated with sleep deprivation.

Finally, Matthew finishes off with his top tips for optimizing your sleep. I know that you are going to love this conversation. Remember, as you are listening, do take notes and think about any questions that you may have on sleep that we do not get a chance to cover. Do let me know what they are and I will put them to Matthew in a future podcast episode which will probably be released in about two months time. Before we get started I do need to give a quick shout out to the sponsors of today's episode who are essential in order for me to put out weekly episodes like this one. Do you struggle with getting enough sleep? If you do you are not alone. One in three adults does not get enough sleep and if you're with getting enough sleep? If you do, you are not alone. One in three

adults does not get enough sleep, and if you're not sleeping enough, it can affect your cognitive functions during the day, like learning, problem solving, and decision making. Sleep deficiency does serious damage, not just to your brain, but to your body as well. We know that the sleepless are much more prone to accidents, weight gain and depression, so getting a good night's sleep is super important for our health. That is why for this special podcast on sleep, I have decided to partner with Calm, my favourite meditation app. Many of you may not know that as well as meditation, the Calm app has a whole library of programmes designed to help you get the sleep your brain and body need, like soundscapes and over a hundred sleep stories narrated by soothing voices like Jerome Flynn from Games of Thrones and Stephen Fry. So if you want some help in improving your sleep,

as well as experiencing all the benefits of meditation, I would highly encourage you to check out the Calm app. Right now, listeners of my podcast get 25% off a Calm premium subscription at calm.com forward slash live more. That's calm, C-A-L-M dot com forward slash live more. 40 million people worldwide have already downloaded Calm. Find out why at calm.com forward slash live more. Athletic Greens continue their long-term support on my podcast and whilst I prefer that people get all of their nutrition from foods, I do recognize that for some of us this is not always possible. Athletic Greens is one of the most nutrient-dense whole food supplements that I've ever come across and contains vitamins, minerals, prebiotics

and digestive enzymes. If you are looking to take something each morning as an insurance policy to make sure that you are meeting your nutritional needs, I can highly recommend it. For listeners of this podcast, if you go to athleticgreens.com forward slash live more, you will be able to access a special offer where you

get a free travel pack box containing 20 servings of Athletic Greens, which is worth around £70 with your first order. You can check it out at athleticgreens.com forward slash live more. Now, on to today's conversation. Matthew, welcome to the podcast. Thank you so much for having me. It's a delight to be chatting again. Lovely. Yeah, Matt, we obviously, we sort of first had contacts over email and we got to do a Facebook live conversation on my Facebook page, which proved a huge hit with my audience.

But, you know, talking over Skype with technology, albeit fantastic, it isn't quite the same as being face to face here. So I'm delighted that you're over here now in London doing a bit of promotion for your book. It's lovely to finally meet you in person, Ragnar. Yeah, it's superb. But I thought we might start just by asking you, how many days have you been in London now for? I arrived on Saturday, so this is my fourth day. Your fourth day.

So look, at the moment it's about, well, we've probably just come past 11 a.m. in the UK, which probably means I'm guessing it's about 3 a.m. in San Francisco. So what's going on with your body clock at the moment so i've you can't cure jet lag there are no cures right now but if you understand how it works you sort of can hack the system a little bit what we know is that for every day that you've been in a new time zone your body can actually catch up by about one hour. So that sort of extra day basically acts like a set of fingers on a wristwatch and it will just kind of tweak it one hour every day.

So I am now four days in. I am only offset by four hours relative to California time. Normally I'm offset by a total of eight hours. I've been here four days, one hour for every day. I'm now four hours separated. That would be the classic case if you just sort of let passage of time work. However, you can speed up that sort of tweak. You can get those fingers to work harder on the wristwatch dial, sort of get closer and faster to the natural new time zone in the following ways. Firstly, you should get lots of daylight exposure in the morning in the new time zone in the following ways. Firstly, you should get lots of daylight exposure

in the morning in the new time zone. So whenever you arrive and then for all of the days afterwards, make sure that you get about 20 to 30 minutes of natural daylight. It doesn't matter if it's cloudy, just that brightness alone is key. If you do go outside, the temptation is to put shades on. Don't do that. Even if it looks, you know, you look fantastic and you look very cool, just for the morning, all I would ask you is don't put shades on because it will diminish that light reset function because it's light that's going to help reset and fast forward that clock. The other critical thing is diet or at least eating. is diet or at least eating.

Food is just as powerful a trigger for resetting your circadian rhythm as light is. We only discovered this probably about sort of eight or nine years ago. And so start eating meals at the regular times in the new time zone. Eat when everyone else is eating. Don't eat when your body tells you that you're hungry. It's harder to do,

but that will help you get back into set as well. The other trick, however, is that if you go out in the afternoon, that's fine, no problem at all. But the afternoon is the time to wear shades. That's the time to start blocking the light, to start to force your body to think it's nighttime, it's darkness,

even though your body clock, California for me, is just starting to wake up. I need to shroud my brain in darkness to try and help reset it. So bright light in the morning, get out in the afternoon, that's fine, but worse shades, and then lots of darkness at night, eat meals regularly, and then try and exercise, usually in the morning if you can. If you do those three things, you can strategically treat jet lag. You can't cure it. You'll still feel a little bit miserable. The only other trick I would say is during traveling. I see a lot of people make the mistake of when they sleep during travel.

It's very natural. If I'm flying over from San Francisco to London, usually leave around 5pm in the evening. Most people, and let's say it's an 11 hour flight, most people will wait until the last sort of four or three hours and go to bed then and sort of sleep late. And I normally arrive about 11 o'clock in the morning London time. That's not the ideal thing to do. Try to sleep on your flight, either early in the flight or in the middle of the flight. And the rule of thumb is make sure that whatever time you want to go to bed in the new time zone that evening, let's say it's, you know, 10 o'clock, count back at least 12 hours or 10 hours. That's the time that you have to wake up on the plane and then stay

awake. You need to build up lots of that healthy sleepiness for you to then fall asleep and stay asleep in the new time zone. Don't sleep too late into the flight. If it's late and you still haven't been sleepy, I would suggest forego sleep, which sounds strange for someone like me. Push through for the rest of the day and then just get to bed early and you'll get into set. So thanks for sharing those tips in terms of how you have tried to combat jet lag. But what's interesting as I hear them is that some of the tips are actually pretty similar to the recommendations you would make to people who are not crossing time zones,

but are just simply trying to improve their quality of sleep. So we'll get into that in just a few moments. I actually am doing that flight to California relatively regularly these days, maybe three to four times a year. And two weeks ago, I went and I tried something different for the very first time. And I've got to say, I had the least jet lag I've ever had on one of my trips to California. And I tried something different for the very first time. And I've got to say, I had the least jet lag I've ever had on one of my trips to California. And, you know, I changed multiple variables. It's very hard to say which one exactly it was. But on the flight out there, so it was a morning flight from London.

So that would be the middle of the night in California. I put on some blue light blockers on the flight. And blue light blockers for a little bit of time. And I was reading, but then I would close my eyes. I put a shade on my eyes and I would just try and sleep. I couldn't sleep that well, but at least I didn't expose myself to light. Then at the time of morning or what would have been morning in California, I took off my nightshades. I did not put on my blue light blockers and actually watched a film so i was exposing myself to blue light from my screen to sort of trick my body say hey you're on morning

time so i've never done that before the other thing is and i think we'll go here next then the other thing i've done a lot recently is reduce my caffeine intake a lot and i think that often when i used to travel i was so habituated to having caffeine that sometimes I would wake up in the new time zone with a bit of a headache because my body was expecting caffeine earlier. It didn't have it. And I think that that was artificially waking me up. So, you know, a few things I did differently. But, you know, caffeine is such a popular topic. Right.

And we don't want to be um start off this conversation on a downer but you know let's go into caffeine i mean how much of a sleep disruptor is caffeine i mean it it is quite significant and one of the problems um you know with those long-haul flights and i would actually love to speak with you know virgin or british airways about this um they serve caffeine liberally yeah and the other thing they serve is alcohol i'd love to speak about that too because both of those are the very best ways to a disrupt your sleep and b actually make your and make it much harder for your 24-hour biological circadian clock to readjust both Both of those will actually take away those fingers on the wristwatch and sort of slow the progression down. But caffeine is a misunderstood drug.

It's a drug, right? You use the term drug and that's interesting. It is a drug. It's what we call a psychoactive stimulant. Everyone knows that caffeine can help alert you and sort of keep you awake that's the thing that's most known caffeine if you look at some data is probably the second most traded commodity on the surface of the planet after oil which i think says everything about our sleep deprived state the other thing about caffeine however that most people don't realize is the time that it is in your system. So most drugs have what we call a half-life, the amount of time it takes for half of that drug to be essentially excreted out your system. Caffeine has a half-life of about six or seven hours, and it's a little dependent

on what type of gene that you have to sort of metabolize the caffeine. But on average, it's about that. But what's interesting is that caffeine has a quarter life of about 12 hours. What this means is that if you have a cup of coffee at noon, a quarter of that caffeine is still circulating around your brain at midnight. So to put that in context, it would be the equivalent of getting into bed. And just before you turn the light out, you swig a quarter of a cup of Starbucks and you hope for a good night of sleep. You know, you would never do that because, you know, but that's exactly, unfortunately, what people do, you know, completely innocently by drinking caffeine, you know, still too late in the afternoon. Yeah, it's a huge problem. caffeine, you know, still too late in the afternoon.

Yeah, it's a huge problem. It's, I think it's a big problem in society. If you, I mean, another way to quantify this is if you just look and I've checked out the data from the Financial Times, the number of Starbucks coffee houses that have arisen over the past 30 years, it's just like an exponential increase. And I think that is an expression of how we're self-medicating our state of sleep deprivation in developed nations. And well, cafe culture is just growing exponentially now, right? It's the new, you know, I talk about it sometimes, it's almost like a new pub culture.

It's cafe culture. You hang out with your friends, you meet up, you get your drink. Typically, it'll be a caffeinated drink. We've now got school kids. You know, I saw in a local village I was walking through recently, after school, I popped into a cafe to get, I think, a bottle of water. I can't really remember, but I popped in and I saw a group of school kids. They must have been maybe 13 or 14. After school, they're sitting in the cafe with their caffeinated drinks, doing their homework together, catching up or whatever. I thought, wow, you know, this has become endemic in society now. We, you know, you call it a drug.

I agree with you. It is a psychoactive substance that we, you know, we use liberally. We let our children have it. We, you know, we're not even, you know, we often don't think about the implications of that. And so many patients of mine tell me that, Dr. Chachi, I know, you know, if caffeine can be a problem for some people, I'm not one of those. Caffeine is fine for me. But more often than not,

when they either reduce their intake or cut it out completely, the sleep quality goes up. And, you know, Sachin Panda, Professor Panda, who, you know, I know you know very well, you both sort of follow each other's research. He was on the podcast a few weeks ago. And, you know, he was saying routinely every year, he will have a bit of a detox from caffeine, he'll go off caffeine. And he says,

when I do that, I have a headache for a few days, but my sleep always improves. I've got more energy and my productivity dramatically increases. And I think that says it all really. It does. And, you know, a number of points that you made that I'd love to circle back around to. Firstly, caffeine is the only psychoactive stimulant that we do give to our children readily, which, you know, is, I think, a concern. And I'm not trying to be sort of, you know, finger pointing or finger wagging. Again, I think it's just that parents probably don't understand the impact of caffeine in that regard. I think the second point comes on to your comment of some people say, look, I'm one of those people who can drink a cup of coffee in the evening, have an espresso after dinner, and I fall asleep fine and I stay asleep.

Now, even if that's true, there was an alarming study that was done where they gave people just one single cup of coffee, a dose of 200 milligrams of caffeine, standard cup of coffee. And then they measured the quality of their deep sleep by tracking these big, powerful brainwaves, these glorious, beautiful, deep brainwaves that bathe all of our brain during deep sleep at night. And it helps also restore the body. deep sleep at night and it helps also restore the body. And what they found was that just one dose of caffeine in the evening decreased the amount of deep sleep by 20%. Now you would have to normally age by about 15 years to produce that type of a deficit in your deep sleep, or you can do it every single night by having a cup of coffee. And what's interesting is that those people will wake up the next morning. They won't remember waking up because they may not have woken up. But the quality of their deep sleep was so poor that they will still then feel unrestored and unrefreshed by their sleep.

I need more caffeine. And so here is the irony that now they're starting to reach for two cups of coffee rather than one. And so develops this dependency cycle, this sort of addiction spiral, as it were. So I think people are perhaps unaware of the true impact of caffeine, how long it sticks around within your system. And even if you feel that you're immune to that evening cup of coffee, how it will still impact your sleep, even though consciously you know nothing about it. it will still impact your sleep, even though consciously you know nothing about it. Well, I think, you know, you raise a really important point there, Matthew, about, you know, knowledge and awareness.

You know, none of us are pointing fingers. You know, I understand caffeine is everywhere. You know, I probably used to overdrink caffeine, and I've altered my behaviour as I've learnt more and more about the research. And I think what we're trying to do is raise awareness of, you know, caffeine is a sleep disruptor. There's just no question about that. And, you know, we can dress it up any way we want, but it is a sleep disruptor. So if anyone is listening to this, if that story that Matthew just mentioned resonates with you, I'd really sort of encourage you to have a little think about your caffeine usage and just see if, can you, can you wind it down a little bit? Can you see, you know,

bit by bit, if by reducing it, it improves your quality of sleep? The recommendation I make in my book is enjoy your caffeine before noon. And I say enjoy, because I get it. People love it. I love a good cup of coffee, but I will not have caffeine after midday. I love a good cup of coffee, but I will not have caffeine after midday. Yeah. And I, you know, I've now actually done what Sachin has done. I would routinely go through sort of a caffeine detox. And right now I'm caffeine free. But, you know, I too would enjoy that cup of coffee or a nice strong cup of, you know, Yorkshire tea.

I have no relationship with them, by the way, in the mornings. And I also love the coffee culture as well. You know, I go out with friends and we grab coffee all the time. And I love that. And I want people to embrace it because I think it's fantastic that there's a social movement sort of circulating around that. All I would say, though, is that, you know, decaffeinated coffee is actually really quite good. And I would struggle. I'd love to do this sort of, you know, the Coke Pepsi challenge with decaffeinated. Just in terms of the taste, you will probably notice that it wouldn't give you sort of the shakes or that sort of slightly anxious state. And you probably know the difference.

But I've really become enamored with decaffeinated coffee and all of its flavors. And I love the cafe bar culture. So I'd love to embrace that. But I do like what you're saying about you sort of patients just thinking a little bit about caffeine and considering it and just trying to try the experiment, you know, sort of set yourself the task, give it a go and see if it works for you. Yeah. I remember about a month after my book came out, someone tweeted me and said, I never ever thought that caffeine was a problem for me, but I've read your book, I've taken your recommendation, I now only have two cups of coffee and I have it before noon, and I've never slept this well in over 30 years. And it's just incredible how such a common

thing that people are doing day to day may be impacting our sleep. And I think you make a really good point that it's like a self-fulfilling prophecy. The more caffeine you drink, the more you need, the more dependent you become, the less good your sleep is. And it just continues. I think we also have to highlight, we're talking about coffee, but I think tea would be similar because it contains caffeine. Green tea, a herbal tea that often people switch to when they're not having tea or coffee,

is also a highly caffeinated drink, so may affect you. You mentioned decaf coffee. You know, I've read some reports saying that decaf coffee does contain some caffeine. Do you know much about that? So decaffeinated coffee is not no caffeinated coffee. So you do have to be, you know, somewhat mindful of that. And they looked and you can sort of search around on the Internet.

There's some good sites that will describe exactly how much some brands have very little caffeine at all. Other brands, however, I was surprised to find can have up to 20 percent caffeine in. So you have five cups of those, you know, and you're well on your way to a standard cup of coffee. So you do have to be a little bit careful. But it's certainly a good way if you're thinking about trying to come off caffeine to sort of psychologically still treat yourself with that. Exactly. And it tastes great, right? Yeah, it does. It's not too bad. So caffeine is something that a lot of us do in the morning um we're also

going to talk a little bit later about alcohol which is something that people often use in the early evening or late evening to help them unwind for beds but you know before we go deep into alcohol because i think that's something that people are incredibly fascinated about because i think that whole term of the nightcap you know know, people, it's there in our vernacular now how it's something that can help you just slip off into sleep. Or can it? We'll find out shortly. But, you know, listeners to my podcast know that I talk about these four key pillars of health that I think have the most impact on the way that we feel, but also that we've got some degree of control over food and movements, which people have been talking about for years, but also sleep and relaxation.

Now, in your book, right at the start, you make a very powerful case why sleep is the foundational pillar of health. I'd love you to talk more about that. Yeah. I used to think that sleep may be the third pillar of good health alongside diet and exercise. But the more I sort of did my research, and the more I read from other people, I realized I was probably wrong. That in fact, sleep is the foundation on which those two other things sit. And I'll give you an example in each. Firstly, for diet and exercise, we know that if people are trying to lose weight, and they're being judicious about their food intake, they're trying to diet, but they're not getting sufficient sleep. 70% of all the weight that they lose will come from lean muscle mass and not fat.

Wow. Because your body becomes very stingy in giving up its fat when you are underslept. So dieting becomes, you know, quite redundant in that regard. You know, you want to keep the muscle, you want to let go of the fat and sleep. Deprivation will do the opposite to you. So that's the first thing. It's a foundational element on which, you know, nutrition sits. And by the way, I'd love to talk all about sort of diet, appetite, sort of increased caloric

intake, increasing exactly what you desire to eat when you're underslept. There's great data there. But let me move over to activity. We've spoken about the foundation on which diet sits. When you are not sleeping sufficient amounts, firstly, the likelihood that you will actually exercise decreases significantly. Your motivation to be physically active drops away. Even if you are physically active, the intensity of your workout will not be as strong. So it's less effective and less efficient. Your things like your vertical jump height, your muscle contraction strength, even the exchange of carbon dioxide and oxygen in your respiratory systems, they get worse when you haven't slept. What's even more frightening,

however, is that your risk for injury increases when you are exercising but not well slept. This is incredible. And they did this great study where they looked at some athletes across a season, and then they tracked their sleep. and then they bucketed those athletes into the different amounts of sleep nine hours eight hours seven hours six hours what they found was a linear relationship between less and less sleep and increasing risk for serious injury during a sports event so there is yet another demonstration of how even if you're trying to be physically active but not getting sufficient sleep, it can be harmful.

The beauty of that part of the relationship and the same for diet is that it's bidirectional. That if you actually, you know, improve your sleep, you can improve those two things. But conversely, those two things will improve sleep. So if you start to correct your diet, you start to sleep better. We've already spoken about caffeine, but physical activity is a great way to enhance both the quality and the quantity of your deep sleep. So physical activity, as long as it's not too close to bedtime, if it's too close, your metabolic rate stays too high, your core body temperature stays too high, and that will prevent sleep. I'm seeing that a lot as well, you know, and I've experienced that myself in terms of squash is one of my favourite games.

But if I play squash at about 7 or 7.30pm, I can't sleep that night. You know, I'm lying in bed at night. I know it's about five-ish for me really is the last time I can go on the squash court, have a great workout, have an enjoyable game and everything seems to have sort of gone back down to normal before I try and sleep at night. And I've seen that a lot with patients, which again, you know, if people are after work, they're trying to fit their workout in, you know, it becomes challenging because the modern world is making it sometimes quite tricky for us to live in harmony with our natural circadian rhythms. But I see that a lot working out intensely in the evening is a problem.

Have you done research on that in your lab? So we've looked at this with body temperature too, you know, and I understand that people, you know, I still want to celebrate and embrace the idea of people exercising. I think that's critical. And even if it's late into the night, best not to do that. But if you do do that, a good way to try and solve the higher core body temperature is to have a bath or a shower right before bed. A hot bath, right? A hot bath is best, yeah, or a hot shower,

because what happens is that all of the blood comes to the surface of your skin. You kind of get nice rosy cheeks. And that acts like this huge thermal radiator taking all of the heat out of the core of your body. And as a consequence, the core body temperature will actually plummet and you will fall asleep easier. That's the reason that it's always easier to fall asleep in a room that's too cold and too hot. Too cold is taking you in the right temperature direction for good sleep so if you do have to work out at some point late into the night you can try that trick but for the most part try and get your workout in a little bit earlier it's a great tip though for people because i know there'll

be many people listening to this who probably do try and get their workouts in in the evening so that's a great little tip that they can put into practice to see if they can you know ensure that that workout doesn't hinder their ability to get good sleep. As you were talking about vertical jump, and as a sportsman myself, this really gets me excited to think, actually, can you improve your performance by sleeping more? And immediately what came into my head is an interview. I think it was an interview, or maybe I heard this comment. I mean, you may know more about this,

but I have heard that Roger Federer may get, I think he's been on record to say he gets 12 hours of sleep a night. I don't know if that's true or not. Have you heard about that at all? Yeah, yeah. So he does. He gets about 12 hours of sleep. And if you look at lots of sports athletes,

you know, LeBron James, the basketball player, he suggests that he gets somewhere between 10 and 11 hours. He splits that. He has a nap routinely during the day of about an hour and logs about sort of 9 to 10 hours at night. Usain Bolt, you know, he says he never gets anything less than nine hours. And I believe for one of his world records, he had only been awake for about 35 minutes because he'd taken a nap right before. I think it was an Olympic gold and a world record that he broke. And he'd only been awake for about 35 minutes because he'd slept. And, you know, this is what, you know, I do some consulting now for some Premier League football teams as well as NBA, NFL in the United States. Because they're starting to realize that sleep is probably the greatest legal performance enhancing drug that you could ever wish for. And it's not just in terms of preparation for exercise, by the way, for which it is spectacular. It's also about recovery. And that's one of the places where I see a lot of their sports

physios perhaps not recognizing what they can do with sleep. They front loaded about before the game, which is great. But often when teams are playing, they're playing multiple games. It's about a season and it's all about maintaining their players' health. And that recovery period after a game, before you play the next game, is key. You know, players will dive into baths of ice to try and reduce swelling and inflammation. Sleep is a critical part of that sports equation. You need sleep on both sides of that. So it's fascinating. I say it just for people who are really interested

in being physically active, maintaining their peak performance. Make sure that you also consider sleep after being physically active as well. When we talk about peak performance, everyone's looking for peak performance these days. Of course, those guys are athletes, right? So their idea of peak performance is probably you know when roger federer is playing in a grand slam tennis match he wants to be operating at peak performance but you know like you know joe public also wants peak

performance in their lives you know they want to be able to wake up feeling refreshed you know maybe get their kids to school without there being a whole load of arguments at home because everyone's underslept and tired yeah they want to get to work and perform well in their job so they feel that they're contributing to whatever work they're doing they're operating at a high level so you know what i guess you know some people may think yeah roger federer lebron james you know yeah sure great for those guys but you know I don't need as much sleep as them. So my question would be, what can we learn from those guys then in terms of how they prioritise sleep? How much sleep do we need every day? But also, in episode 14 of this podcast, it was a few episodes ago, I interviewed Nick Littlehales, who for many years has been advising clubs like Manchester United, the England football team. And he talks about this idea of 90-minute sleep cycles.

I don't know if you've read his book or you're familiar with his recommendation. But I find it, you know, he talks about this whole idea of five 90-minute cycles that we need throughout the day. And I know some people found that quite helpful to take the pressure off them at night. So quite a few questions there, Matt, but I wonder if we could just try and go into those areas a little bit. Yeah, so right now the recommendation is for most adults get seven to nine hours of sleep. And to get, by the way, to get seven hours of sleep, you probably need at least a seven and a half hour sleep opportunity. I think that's what many people miss in recommendations from sort of experts. They say, get your seven hours of sleep. So people

think that means, you know, well, if I go to bed at 11 PM and I wake up at 6 AM, then I've got my seven hours of sleep. That's not true. You probably will have only logged about sort of six hours and 40 minutes and that's not enough. So you need to think about the sleep opportunity time as being probably around about eight hours optimally. What we also know is that once you get below seven, we can start to measure objective impairments in your body and in your brain as well. The problem is that most people don't realize that they're sleep deprived when they're sleep deprived. This is a big problem with sleep loss. And, you know, the analogy, I guess, would be a drunk driver at a bar. You know, they've had a couple of pints,

maybe a few shots, and they pick up their car keys and they say to you, you know, look, I'm fine to drive home. And you say, no, I know that you think you're fine to drive home, but trust me, you're not. You are objectively, you're impaired. It's the same way with a lack of sleep, that our subjective sense is a miserable predictor of objectively how well we're doing with a lack of sleep. And I think that's one of the issues that I try to sort of help dismiss in terms of a notion. I think the other thing that's problematic too about getting too little sleep is that your baseline level of how you think your health and your wellness is just becomes chronically low. And you accept that as if that's just where I am in life. This is just me. This is as good as it can be be and people don't realize that if you're to change something

like sleep or stress or diet or physical activity there's actually a better form of you waiting on the other side of those things it just requires perhaps you know some knowledge and an invitation to go there matthew i i call this podcast feel better Better, Live More, for a reason. And it really just echoes what you just said then, you know, when we feel better by, you know, prioritising sleep, by, you know, looking at these other pillars that I talk about, we get more out of life. We're a better version of ourselves. We have better relationships. We have, you know, much deeper, more meaningful interactions with the world around us when we're feeling better. And I guess you would argue that when we sleep better, we live more. We do. I mean, firstly, that data is very clear that if you look across epidemiological studies,

millions of individuals in these studies, a very simple truth comes out, which is that the shorter your sleep, the shorter your life. That short sleep predicts all-cause mortality. Wow. And so, you know, I think... I think we just need to stop and just let that sink in for a minute. Depriving ourselves from sleep will shorten our life. Yeah. Yeah, I mean...

That's the powerful data that, you know, the global sleep loss epidemic that is underway right now, which I believe is probably one of the greatest public health challenges that we now face in the 21st century, it is a slow form of self-euthanasia. It's a very powerful statement, one that I absolutely would agree with. Have we as a society, have we put too much focus on the right food and the right physical activity at the expense of sleep? Yeah, it's a great question. I've thought about this a lot. I don't think we've done it at the expense of sleep perhaps, but I do resonate with your comment that I think sleep has perhaps been

the neglected stepsister in the health conversation of today. And I think it's been left out in the cold. There's probably a number of reasons for that. The first is just because scientists like me are to blame. What I mean is that we have not adequately communicated to the public or to medicine or to healthcare professionals in general how critical the importance and necessity of sleep is. You know, and I liken where we are with sleep with where we were for smoking 50 years ago. You know, all of the science was there,

but it hadn't trickled down into the public knowledge base or even into medicine. That's what you do so great with your book is you're bringing that awareness to the general public all over the world, which is fantastic. And that was part of the motivation for the book. You know, I could see the disease and sickness and ill health that was caused by insufficient sleep. And there wasn't, you know, there wasn't a blueprint guide. There wasn't some kind of a manifesto for sleep. And so that was part of the reason to write the book.

But I think to come back, you know, to why sleep is being left out in the cold, I think part of it is people like, you know, well, at least my fault. I think the other thing too, is that unlike diet and exercise, sleep has an image problem. You know, I think nobody feels ashamed about saying, I went out for a run at lunchtime, or, you know, I went, I had a great run this morning. Nobody necessarily feels ashamed about,, I went out for a run at lunchtime, or, you know, I went, I had a great run this morning. Nobody necessarily feels ashamed about, you know, putting salad on their plate, you know, and making a really healthy meal. But I do think people feel sometimes ashamed by saying, well, I need at least eight and a half hours of sleep a night. You know, and sometimes I've heard the reaction of people saying, really?

And that really has a hint in it to suggest that if you're getting sufficient sleep, and I choose that word carefully, sufficient, then you must be lazy that you're slothful. Because we've tagged and we've associated this thing called necessary sleep with that luggage of, you know, something to be ashamed about. And in fact, if anything, it's what happens is that people have this braggadocio attitude, this almost sort of sleep machismo attitude that you're very proud to tell people how little sleep that you're getting as though it's, you know, a badge of honor. I see that in some people, not all people, but some people. So I think to change that part of the sleep discussion

and bring it into the health equation, we need to de-stigmatize sleep in a way too. I think those are at least two of the reasons why it's being left out in the cold. Yeah, yeah, absolutely. I mean, I, you know, I've shared this before on the podcast that a few years ago, for me, it was probably when I had kids, actually, because my kids were early risers. And, you know, that's the understatement of the year, that they were early risers. But I realised that if I didn't alter my going to bedtime, I was going to be exhausted every single day, which is what was happening. And I sort of altered my whole sleep schedule a few years back. And it's something now that I really do prioritise. You know, I will have a shut off time in the evening after which I'm not on my computer.

I'm not working. I will wait because I know that if I don't do that the next day, I won't be performing anywhere near the level I want to. And it actually reminds me of that Facebook conversation we had, the Facebook live chat we did. So guys, we were trying to schedule this chat for a little while. And we put a date in and then Matthew had to move the time. And I got an email, I think from your publicist saying, you know, can we move this time? And I thought, well, that's 9pm UK time. Man, that's really late because, you know, I've just written a book saying how important sleep is as well I'm trying to

educate and inspire my audience that actually these things are really important so I actually declined your very kind invitation to do it in 9pm I just actually asked to see if we could change the time I certainly wouldn't have suggested Yeah I said guys look, we chat between 9 and 10 and we

talk about how detrimental sleep is and, you know, and all the problems associated with it. Yet we're doing it late in the evening for my UK audience. I'm going to expose everyone to blue light in the evening on their devices, emotionally work them up before bed. I thought, actually, you know what, let's just decline that and do it another time. So I thought that was quite nice. Yeah, that was great, wasn't it? Yeah, it was just, you know, for someone to embrace, you know, sort of and practice what they preach.

And, you know, and I think for the two of us, you know, a lot of people, of course, will ask me, well, so how much sleep do you get? And I will tell them that I do honestly get a non-negotiable eight hour sleep opportunity every night. And it's, I'm not trying to be, you know, a poster child for sleep. I'm not trying to just sort of promote the book. If you knew the data as I do, and as I hope people will after reading the book, honestly, you just would not choose to do anything else.

And, you know, I don't want to live a shorter life and I don't want to live a shorter life that is filled with disease or sickness. And from everything I can tell, sleep is perhaps one of the most democratic, freely available, efficacious forms of health insurance that you could ever wish for. And as a consequence, the reason I get that much is because for selfish reasons, you know, I just want to be alive and well for as long as possible. And I think, you know, it's interesting hearing you say why you prioritize it. You know, again, it's selfish is the wrong word, but it's for self-preservation reasons. And one of the things I actually, if you don't mind, I know this is your podcast and you're interviewing me. You can talk about whatever you want.

But I would love to just ask you the question, because, you know, when I saw the title of the book, you know, and I saw that, you know, there on the front cover was this word called sleep. On my book? On the front cover of your book front cover was this word called sleep. On my book? On the front cover of your book, there was this thing called sleep. Relax, eat, move, and sleep. And I well imagined that the first three would be there, of course, from, you know, an eminent clinician. But I was surprised by the four. I was lovely excited. It was wonderful.

But tell me, you know know where did that decision come from to include sleep you know where did you get the awareness from where did you get the sensitivity to sleep you know was it boots on the ground with patients was it in a medical curriculum was it personal tell me i'd love to know yeah i think matthew that's a great question, really. I mean, I guess my journey into this, of really being keen to promote lifestyle, comes from a real feeling that in medicine we've lost our way a little bit. Now, we're not putting blame on anyone. the medical system is set up around acute diseases, acute problems that respond very well to our magic bullet pharmaceutical interventions. But I think the health landscape, even in my career, and I've nearly been seeing patients now for about 20 years, even in my career, I've seen the health landscape of the patients that I see change dramatically. Whereas now the bulk of what I see in my daily practice, you know, I say 80% of it is in some way driven by our collective modern lifestyles. And so I've been delving deep

for a few years now in terms of, you know, what are those lifestyle factors that I can leverage with my patients to get a better outcome? And of course, when I first started going on this journey, it was all about food, right? You know, when I first started going on this journey, it was all about food, right? It's all about diet. And if we were having this chat five or six years ago, I would be saying, most of what happens to us, most of our health determinant is basically foods. But I disagree now, because I think when you know the science, when you have seen the science, as you detail so beautifully in your book, the case is compelling. You can't really ignore sleep.

So I'm a doctor who wants to get my patients better, like every other doctor. I want to do this in as harmless a way as possible. And I also get very tired of suppressing downstream symptoms. of suppressing downstream symptoms. So I want to go upstream as far as possible, see what lever can I turn that's going to have all these downstream consequences. And food is one of those things that, you know, food isn't just calories, you know, it's not just fat and carbs, it's information. It changes our genetic expression. So it's information for the body. In a similar way, physical activity can change hormones, can change genetic expression, all these kinds of things. And, you know, so obviously that's food, that's

movement. Relaxation is a whole piece about stress, you know, which, you know, some research is showing that up to 90% of what we see in primary care may have stress as a factor, which is incredible. But I always thought I was missing one piece off the puzzle. And I would see, if we take autoimmune disease as an example, when I see my patients, I often do what's called a timeline. And I look, I say, okay, you've got symptoms here today, but let's look at your whole life. Let's see what's been happening sequentially. Because I don't think a lot of these chronic conditions just happen overnight. There's been a buildup for a period of time, for a period of years. And I would often see with autoimmune

conditions that just a few months, sometimes just one month before the onset of symptoms, I would see either... Well, not either. I would often see a really stressful episode happen that would reduce the quality of people's sleep and then i see symptoms come on yeah there was a doctor i always want to learn from my patients so you know your question is where does this come from well primarily it's come from listening to my patients and listening to the stories that they tell me because you know you're you know one of the world's eminent researchers in sleep. I love research, but I also love real life. What happens at the coalface when I'm seeing patients?

What do they tell me is working? What do they tell me they're struggling with? That also influences a lot of my recommendations as well as the science. You know, if you can marry those two together, I think that's when we can make a real difference with people. And I also went to a conference in San Diego about two years ago, and the whole conference was on sleep and relaxation and rest. And I think it was Phyllis Zay. Do you know Phyllis?

Philis Zay. Yeah. Philis Zay. She gave a couple of keynotes there. And I thought, God, this really is wetting my appetite. It's really reinforcing what I'm seeing in my practice. As I say, when you look at the research, I thought, well, how can I write a lifestyle book that is to empower people to take control of their health and not cover sleep? You know, I can't do it. I just, I just can't do it. So interesting about that is, you know, you had, you know, all of this time at medical school in practice, you know, and it took a conference, you know, that you, you know, through your own sheer interest and desire to try and help. My own money, my own sort of annual leave to go and do this stuff because I'm interested. That's where you got your sleep education.

You know, that strikes me as so, you know, unfortunate. you know, unfortunate. You know, I want to think, I want to work with medical systems to try and increase, you know, a sleep education component, because wouldn't it be wonderful if all of our primary care physicians here in the United Kingdom were, you know, as sleep aware and sleep motivated as you are. And I'm sure they would be delighted to receive that information. You know, I have lots of friends here who are doctors and, you know, I know that they would embrace that and would love to try and increase wellness in their patients. But there's just no pathway that we've engineered in the medical system to gift them with that knowledge and dispense wellness to their patients. Because sleep really is the tide that raises all of the other health boats. It's just as you said, it's the superordinate node

that if you manipulate it, it's like the Archimedes lever, you pull that, everything else can start to come into play. You get the sleep better, it affects your brain, it affects your hormones, it affects your genetic expression, it affects all these sort of things that we might be looking for drugs to, to affect those individual pathways,

but you can improve a lot of them by improving your sleep. Yeah, you know, and it's no, we think, well, that sounds almost too good. But don't forget, you know, it took Mother Nature 3.6 million years to evolve this necessity of eight hours of sleep in place, which I should note, by the way, that if you look at the data back in the 1940s, the average adult was sleeping about 7.9 hours of sleep. Now that number here in the United Kingdom is closer to 6 hours and 30 minutes. In other words, within the space of 100 years, which is a blink of an evolutionary eye, we've lopped off almost 20% of our sleep need. You know, how could that not come with demonstrable health and disease consequence? So I think, you know, there's that component there.

But I love what you're saying that, you know, in medicine, we're often, or even in research and pharmaceuticals, we're often trying to sort of manipulate one pathway in one area of the metabolic system or one aspect of the immune system or one feature of the cardiovascular system. And, you know, sleep affects all of those. And we can, you know, I'll give you an example. Firstly, we know that if you get a patient and you have them sleeping just six hours for one week, this is someone, let's say, who is healthy. At the end of that one week of short sleep, their blood sugar levels are disrupted so significantly that they would be pre-diabetic, that you would diagnose them as being in a state of pre-diabetic. Just from sleep deprivation. Just from sleep deprivation. Just from sleep deprivation and control all of the factors. You can also speak about sleep loss and the cardiovascular system.

And all it takes is one hour of lost sleep because there is a global experiment that's performed on 1.6 billion people across 70 countries twice a year. And it's called daylight savings time. And it turns out that when you look at that data in the spring, when we lose an hour of sleep, we see a subsequent 24% increase in heart attacks as a result. It's just incredible. But in the autumn, you know, when we gain an hour of sleep, we see a 21% reduction in heart attacks. So the data is there on a global level, isn't it? Just from that. It's striking. And you can even think, you speak a lot about the immune system. It's so

key for our health. So tell us, what does sleep do for the immune system? So firstly, we can look on both sides of the coin. What happens when we don't get enough sleep? Firstly, we know that people who are sleeping five hours a night are four times more likely to catch a cold than those people who are sleeping eight hours or more. Striking study, very well controlled study. We also know that it doesn't take one week of, you know, short sleep deprivation. One night is enough. that if you take healthy individuals and then we limit them to just four hours of sleep for one single night what we see is a 70 drop in critical anti-cancer fighting immune cells called natural killer cells which are these wonderful sort of immune assassins that you know help decrease our

you know sort of you know cancer risk yeah and help us fight infections. And fight infection. Part of our innate immune system. Exactly. Part of that critical innate immune response flipped the side of the coin. And now what we find is that when you get sleep, there is a change in what we call the autonomic nervous system, which is sort of this automatic part of our nervous system. And that automatic nervous system is split into two branches. One that is sort of like the accelerator pedal that gets us revved up, triggers the fight or flight response. The other is the brake that sort of calms us down. And when we go into deep sleep, we apply that brake to the nervous system and everything quiets down. Heart rate decreases. Deep sleep is the most wonderful form of natural blood pressure medication that you could ever wish for. But one of the other things is that we see as that nervous system quiets down, levels of things like cortisol drop down, that stress-related chemical. And it's during that

time that the body goes into an immune stimulation mode. And it's where essentially you're going to restock the armament of your immune army so that when you wake up the next day, you can battle and fight infection. What's also fascinating, and I love this data, and this tells you just how critical sleep is to a fighting for our health. If you look at people who become infected or you actually infect them in the experimental laboratory, let's say with sort of a cold vaccine, you immediately trigger increased sleepiness and increased amounts of deep sleep. And it turns out that the infection indicates to the immune system that you're under attack and the immune system will actually signal to the sleep system within the brain, we need more sleep.

Sleep is the best battle force that we have right now to combat this assault. And so that's why when you're sick, all you tend to want to do is just curl up in bed and go to sleep. The reason is because your body is trying to sleep you well. That's an appropriate response to what's going on, right? Exactly. Our bodies are pretty clever, right? They are remarkably clever. You know, again, Mother Nature has figured this out.

And so she brings up this thing called sleep, which I would argue is probably like the Swiss Army knife of health. You know, whatever ailment you are facing, it is more than likely that sleep has a tool in the box to try and help fight it. That's so key. Whatever ailment you're facing, guys, if you listen to this, whatever you're suffering from,

whether it's a lack of energy on a day-to-day basis, or whether it's that you're worried about your risk of developing a chronic disease such as type 2 diabetes or heart problems as you get older you know what matthew is saying what professor walker is saying is that sleep improving your quality of sleep is going to help you with all these different facets it's going to help reduce your risk it's going to help increase your energy it's also going to reduce your risk of actually getting disease in the future which is is just absolutely incredible. I mean,

we are going to move on to tips because I know many of you will be thinking, okay, this is all great. I'm sort of hearing about all these things that sleep does, but how do I get more? So we're going to come to that shortly. But so much I want to talk to you about, Matthew. I mean, I think we could easily make this like a full day podcast. I'm that fascinated in this. I'd love to return at some point, should you wish me to. Yeah, well, 100%. But I think, you know, what you said about medical school training,

I think it's very important because pretty much everything that I put in here and then the last quarter of the book is on sleep. I'm not convinced that any of that came from my medical school training. So that was all self-taught from, you know, spending hours on PubMed, reading research,

going to conferences, trying to learn more because I wanted to help my patients more. I thought, you know, I need to know more about this so I can actually do my patients, you know, and give them a better service. So you're saying that, you know, maybe medical students may get maybe two hours or so and you'd love to sort of try and help that and get maybe a sleep curriculum into medical schools.

And this really, I think one of the reasons we get on so well is there's so much synergy in our viewpoint in terms of how we think this needs to change. So what I've done over the past six months is develop a brand new course with a colleague of mine, Dr. Panjshir, called Prescribing Lifestyle Medicine. And it's a one-day masterclass to teach healthcare professionals, but primarily doctors, on the basics of lifestyle medicine,

if you will, as a term. So we go into sleep and we teach this framework where they can simply apply these four pillars with their patients to start to actually implement lifestyle medicine. I'd love to, you know, love to maybe collaborate with you and show you the slides. I'd love to. And I've got, you know, I teach a whole course at the University of California, Berkeley, the science of sleep. So I've got lots of slides. I'd love to just share and do whatever I could to try and help sort of perpetuate that movement that you've got going. It's wonderful. That's exactly what we need.

Yeah. And then maybe we can talk about how we get that into medical schools. And, you know, I was going to actually ask you, you know, how could we, you know, even collectively, you know, think about trying to, you know, approach sort of medicine here in the United Kingdom and see if we could. We'll talk about that off the air from the podcast. That could be a great collaboration. Matthew, I know you're short on time. And again, we could just go on for so long.

I was going to ask you about sleep and stress, but I think, you know, guys, for those of you listening to this, I cover that in quite a bit of detail, I think, with you on my chat that's on my Facebook page, which is facebook.com forward slash DrChatterjee. So guys, you can actually check it out there. But everything that Matthew and I talk about, including that Lancet paper that he mentioned,

is going to be in the show notes, which is going to be at drchatterjee.com forward slash Why We Sleep. There's going to be links there to everything Matthew talks about, some of Matthew's articles, his book, all kinds of things. So guys, do check that out after the podcast and you can do a bit of further reading on those topics that interest you. So, yeah, where to go to next?

I mean, one thing that we do talk about on that course, and I think we've not spoken about this yet, is about sleep and its role in mental health. is about sleep and its role in mental health. And, you know, what's interesting, you mentioned bi-directional relationships before and how a lack of sleep can increase our risk of problems, but also sleep can be a treatment as well for various things. And I wonder if you could talk about that in relation to mental health problems such as anxiety and depression, and maybe from there just move briefly on to Alzheimer's if possible.

Yeah. So we've done a lot of work in this area of sort of sleep and mental health. I think the first point to note is that we have not been able to discover a single psychiatric condition in which sleep is normal. And I think sleep has a profound story to tell in our understanding, in our treatment, maybe even ultimately at some point our prevention of grave mental illness. And I don't say that flippantly. Firstly, we've done some work where you can take healthy individuals and you can deprive them of sleep for a single night. And then you place them inside an MRI scanner, and you look at how their brain has changed. And what we find is that these deep emotional brain centers erupt when you're sleep deprived. You become a lot more emotionally reactive, impulsive. There's a deep brain center called the amygdala, which is one of the centerpiece regions for the generation of strong emotions.

That part of the brain is up to 60% more reactive when you're sleep deprived relative to when you've had a good solid night of sleep and we've also found a huge amount it's a 60% it's very difficult to usually see that type of a change in the brain without some kind of pathology or drug and I think deprivation I think on an intuitive level most people recognize that when they haven't slept well, they're just a little bit more reactive to things. That email from their boss, for example, can be easily misinterpreted. Are they annoyed at me?

You suddenly start to see things that aren't there. I mentioned this before. I've just completed my second book called The Stress Solution, which is going to come out in January. I cover a little bit of this that you're talking about in that to really try and show people that lack of sleep is a stress on our body. And 60%, that's incredible. Change in the brain, yeah. And I think it really comes, you know, you're absolutely right. Many of us have a sense that, you know, I just snapped, dot, dot, dot. You know, those are the words that usually follow a bad night of sleep

or when you've not got enough sleep. And we know it all the way down sort of the age chain. You know, you think about a parent holding a child. The child is crying and they look at you and they say, well, they just didn't sleep well last night. As if there's some universal knowledge that bad sleep the night before equals bad mood and emotional reactivity the next day. And it doesn't stop in infancy or childhood or adolescence. It's true when we are adults as well. And it doesn't stop in infancy or childhood or adolescence. It's true when we are adults as well. And we've seen this data. What I think is concerning is that that neurological

signature that we discovered in that study is not dissimilar to numerous psychiatric conditions. And in fact, we're now finding significant links between sleep disruption and depression, anxiety, links between sleep disruption and depression, anxiety, including PTSD, schizophrenia, and most recently and tragically, suicide as well. In fact, a short sleep duration is usually predictive of either suicidal ideation, suicidal thoughts, suicide attempts, and tragically, suicide completion. So I think the scope through which sleep is impacting mental health disease, I think is considerable. We used to think in psychiatry that the psychiatric disease was perhaps causing the sleep disruption. I think now we've been forced to change our minds. It's not as though it's completely in the opposite direction. It's not that every psychiatric condition is a sleep disorder.

That's not true either. But is it a two-way street? I think that that's probably more tenable. In fact, is the dominant flow of traffic perhaps more in one direction than the other? I think that's also reasonable to assume on the basis of the data right now as well. So I think there's clearly an intimate relationship between our mental health and our sleep health. Matthew, the implications of what you just said, I think, are so profound. We've got to accept in the 21st century, not only do we not prioritise sleep enough, we are a chronically sleep deprived society.

We're now going through a mental health epidemic. You know, Mind, the charity here in the UK, say that about one in four people in the UK now in any given year are going to be diagnosed with a mental health problem. Now, that's incredible. And when you hear about that research, we think, chronically sleep-deprived society, mental health problems otherwise, yes, there are other factors, okay? I don't think you or... Both think you both of us agree on that we're not trying to say it's all to

do with sleep but what we are trying to say is that sleep is a critical part of the equation and one that we can no longer afford to ignore um so i find that research fascinating you know and it makes me think as a doctor, you've mentioned already type 2 diabetes, heart disease, mental health problems such as depression and anxiety. I know at our previous discussion, again, guys, I'd point you to that Facebook discussion because we won't have time to go into this today, but we will when I get you back on the podcast.

On our Facebook discussion, we did go into Alzheimer's and how sleep deprivation, you feel, may be causative now or one of the causative factors that causes Alzheimer's disease. I'm thinking, well, I often say this when I'm teaching doctors,

why are we not bringing up sleep quality with pretty much every single patient that walks in through our door. You know, and you could imagine the cost savings to, you know, our economy. In fact, the Rand Corporation recently did a survey, the enormous cost of sleep deprivation throughout a number of developed nations. What they found was that a lack of sleep costs most nations about 2% of their GDP. So here in the United Kingdom, that's 30 billion pounds of lost economic value

caused by insufficient sleep. In the United States, it was $411 billion. In Japan, it was $138 billion. In other words, if you solve the sleep loss epidemic, imagine you could almost double the budget for education or you could perhaps even half the healthcare deficit. You know, Theresa May just this double the budget for education or you could perhaps even half the health care deficit. You know, Theresa May just this week, as we're speaking here, the prime minister of the United Kingdom, described a 20 billion pound injection of funds into the national health care system. And there's uproar about where that money is going to come from. Well, you know, if we just simply prioritised and solved the sleep epidemic, the sleep loss epidemic,

we could cover that and still have £10 billion left over. Yeah, and this podcast doesn't sound to be too political, but I would say that, you know, I find a lot of the messaging around the NHS in public very short-sighted. It's about pumping more money in to fix downstream issues, whereas we've got to look at prioritising sleep as a society, whether it's the lighting that's used in hospitals

when patients are trying to recover from illness, which isn't very helpful a lot of the time, whether it's teaching our children about it and encouraging good habits at school, but also as parents with our kids, really ingraining. And I think we've not really got into technology today and how the overuse of technology can potentially be problematic for sleep. I agree, sleep, it's such a simple lever to turn.

It's also, well, we'll come into tips in just a second, but so many health inequalities are there from people from different socioeconomic groups. We know in the UK that you can have as much of a 10-year difference in your life expectancy depending on where you live. One thing I like about a focus on sleep, and I appreciate that there are many pressures in deprived communities, financial stresses, maybe a lot of shift work, maybe working multiple jobs. So I absolutely understand and recognize that there are significant issues that we have to overcome. But a lot of the recommendations that we're now going to talk about that I cover in my book and you cover in detail in your book, most of the recommendations to help people to, you know, get more quality sleep

are free of charge. Yeah. You know, I often say that I think sleep is perhaps the most democratically freely available healthcare system for everyone around the world. Now, that's a bit of a glib statement on the basis of exactly what you just said, I think about, and the data is quite frightening. We've been looking at this too, at sort of low socioeconomic status communities. And there, what you'd see is just what you described, you know, higher general social stress that impairs sleep, usually working multiple different jobs,

split shifts, working the night work. Often people in those communities are working in the service industry. That usually means that you're either up very early or you're staying in work very late, all of which comprise, you know, factors that work against sleep. So I want to be really appreciative of that. But still, I think, you know, the tips that we can do right now to start sleeping better every night should be applicable and for the most part utilized by just about everyone, as long as you don't have

a sleep disorder. Well, Matthew, normally I end the podcast off by asking people for four key tips that people can put into practice immediately, but we don't have to limit it to four. I want this podcast to inspire people to not only take sleep seriously, but to give them some practical help. So immediately after listening to this, I can put the headphones down and go, right, I'm going to do what Professor Walker's asked me to do. I'm going to try these five things today. In your experience, and you've been interviewed all around the world now to do with your book, what are those common things that people aren't doing that they could do to help improve their sleep? Yeah, so there's probably maybe five things

that people can do right now to get better sleep. The first is regularity. Going to bed at the same time and waking up at the same time, no matter what, even if you've had a bad night of sleep, still try to wake up at the same time. Just understand it's going to be a tough next day and then get to bed at the same time that following night and you'll have a good night of sleep you'll sort of sleep a little bit more soundly that night even if it's the weekday or the weekend don't do so what we call social jet lag which is sort of where you sort of sleep too late at the weekend and then on sunday night you've got to drag your body clock all the way back and try and force it to sleep at a time when you haven't been sleeping before. That's torture. Regularity is key. The second thing is temperature. We've spoken a little bit about that, but keep your bedroom cool and probably around about 18 degrees Celsius, which

is colder than most people think. But cooling the room down takes your body into that right sort of thermal space for good sleep. It cools it down. Darkness, we've spoken about too, but we are, I think, a dark deprived society in this modern era. And you need darkness at night to allow the release of a hormone called melatonin, which helps time the healthy onset of your sleep. So yes, it's to do with blue light sort of emitting devices, screens, phones. Those are things that you should try and stay away from in the last hour before bed.

But it's not just that. It's also overhead lighting. You know, we don't need to be bathed in electric light all night. In the last hour before bed, just try turning half of the lights off in your flat or in your home. You'd be surprised at how soporific and sleepy you become when you're

shrouded in darkness. So that's the third thing. The fourth thing is, I would say, walk it out. And what I mean by that is don't stay in bed if you've been awake for 20 or 25 minutes, either trying to fall asleep or you've woken up and you're trying to get back to sleep. The reason is because your brain is this wonderfully associative device, and it will start to very quickly learn that being in bed is about being awake rather than asleep. So what you need to do is after about 25 minutes, just relax, understand that sleep is not quite here yet. Go to a different room in dim light, read a book or listen to a podcast, but don't check email, don't eat because it trains your brain to expect that in the middle of the night.

Only return to bed when you are very sleepy. And that way your brain will start to relearn the association that your bedroom is the place of sleep rather than the place of sleep. I think that's a really important tip, Matthew, that I know even from our first conversation on Facebook, but whenever I talk about sleep, people can often get really wound up about this and say, I'm doing all those things, I can't sleep. And they've really just, without trying to, their brain has just got into this position where it's been trained not to sleep. It's been trained to not associate the bedroom with sleep. Or, you know, so many people I see, you know, when I hear about on social media are doing work emails right up to the moment they fall asleep.

And, you know, we mentioned children before. And I often say, you know, children need a bedtime routine. We know that. Why as adults do we think we're any different? We should. And you're absolutely right. You know, we've turned the bed in this day and age often, you know, into a kitchen. We've turned it into an office. We've turned it into a cinema. You know, we do all of these things typically on the bed, which then it does impact the brain's association. It gets quite confused about what this thing called the bed is all about.

it gets quite confused about what this thing called the bed is all about. So I think that that's a very helpful tip. And try not to get too anxious if you're sort of falling asleep. I know that probably a lot of what I've been telling people will make you feel anxious if you're not being able to get the sleep that you need. But try not to worry about it. Everyone has a bad night of sleep. Just get up, understand that you're going to be awake for a little bit longer and then go back to bed and you will start to relearn that association. And in fact, a lot of, you know, people and patients will say to me, well, you know, I've been falling asleep on the settee watching television and then I get into bed and I'm wide awake and I don't know why. And again, it's because of this association that you've learned with the bed. The final two things, one of which we've mentioned, is what you intake into your body, caffeine and alcohol.

We've spoken about caffeine, but I'll speak about alcohol quickly. Many people use alcohol as a sleep aid, and it is anything but an assistant to sleep. Alcohol is a class of drugs that we call the sedatives and sedation is not sleep. Unfortunately, it's very different. So what you're doing when you have a nightcap or you use alcohol to try and get to sleep, and many people do understandably so, they mistake one for the other. You're just knocking your cortex out. You're not in natural sleep. The two other problems with alcohol and sleep, firstly, alcohol will fragment your sleep. So if I were to record someone's sleep in the laboratory after they've had a couple of drinks,

their sleep is littered with all of these awakenings throughout the night. Now, you tend not to remember waking up, but the next day you feel, again, unrefreshed. You don't feel sort of bright and alert or restored by your sleep, but you don't remember waking up, so you don't link it to the alcohol. But alcohol is bad at fragmenting your sleep, produces poor quality. The final thing alcohol is good at doing is blocking your dream sleep or your REM sleep. And we know, to come back to our conversation, REM sleep is critical for emotional first aid. REM sleep provides overnight therapy. It's a form of emotional convalescence and alcohol will block that REM sleep quite viciously. So those would

be the five tips I think for better sleep. Yeah, Matthew, thanks. I love that. Just to say on alcohol, is it dose dependent? So for example, you know, some people say, well, I'm okay with one glass of wine but two or three glasses is going to fragment my sleep you know can you comment on on the dosage there or would you advise people who are struggling with sleep to knock it on its head basically i know and it's so hard for me to answer this and this is the reason one of the many reasons why i'm in such a deeply unpopular person but i don't think that's fair to say, but I, but you know, I, firstly, I don't want to sound puritanical, you know, life is to be lived to a degree and all of

these things that we're discussing, we're trying to speak about the extremes. Um, but I also want to empower people with the knowledge. I'm not here to tell you necessarily what you should or you shouldn't do. I just want to give you the scientific facts and then you can make the choice. I would say, unfortunately, that even just one glass of alcohol in the evening, we can see that, we can measure that. You can measure that. In your lab, you can see that you're not getting the same deep level of restorative sleep, even with one drink. Even with one drink. So I know it's hard, but now, you know, everyone, you know, should, you know, have a social life and sort of, you know, enjoy a drink now and again. I think the best advice would be this.

If you're going to bed feeling tipsy, you probably have had too much alcohol in terms of sleep impairment. I think, you know, I so resonate with it with so much of what you've just said, which is, you know, this podcast, what I do, what you do. It's not about telling people what to do. I've got no interest of telling someone what they should do. I have no right to tell someone what they should do with their lives. What I think we're trying to do is to educate people, inspire them, empower them to understand what lifestyle choices they're making and how that could impact their health. And I always draw the analogy with going out, how many of you drink with your mates on a Friday night? People know intuitively that if I

go out for a drink on a Friday night and have three or four pints, let's say, you know what, my Saturday morning might be a bit of a write-off. I may not be functioning as well as I might want to. But you're going into that with that knowledge. You're saying, you know, I know the effects alcohol has on me, but I'm going to get so much enjoyment out of my night out tonight that I'm willing to put up with the consequences. What I think we're both trying to say is, guys, we just want to empower you. We want to help you understand the impact that caffeine might be having on your sleep, that alcohol might be having on your sleep, that the fact that you're on your work emails before you go to bed might be having on your sleep, that alcohol might be having on your sleep, that the fact that you're on your work emails before you go to bed

might be having on your sleep, do with that information what you will. That's how I would put it. I so agree because I think a lot of what you speak about in your book, which is far more wide-ranging than mine, because I just take one of the things, you go after four of the key pillars,

which is so much more impressive. I think it says so much about the difference between me and you, Rangan. Well, you're a recent, I'm a clinician, right? There's a big difference, right? There is, but I still think it's a heroic thing. But what I would say, I think, is that, yes, a lot of people are aware of some of these things, you know, like it's good to be physically active, you know, I should try and stay away from drinking too much alcohol. But I also think that there's a lot of what we discuss, you know, I hope in both books, that is perhaps knowledge that people aren't aware of. And if only that they were aware of it, they would actually want to do something different.

That's the sort of the case that I'm really passionate about, is that people, as long as you know the information and you choose to do otherwise, no problem at all. A lot of people just are either misinformed or entirely, when it comes to sleep, uninformed. That's the goal. That is the goal. And it's really about, it's that empowerment piece. And this is one thing I just want to end on is just to say, guys, look, it may not be that you can just change one thing and suddenly have a great night's sleep. You might have to change three or four things together. You know, that's certainly my experience. It's like, you know, Matthew, you know, you're a researcher, so a lot,

you know, you'll do research on showing what caffeine does, on showing what alcohol does. But I would say as a clinician, use that research, but maybe you might have to try a few things. Like you might try, for example, one week with no caffeine and no alcohol and see how you sleep because then you can be empowered to just to decide what are you going to do after that are you going to go back or maybe then i always try and get people sleeping as well as they've ever slept then they can start reintroducing some of these lifestyle things that they want and they can say oh wow that's interesting i i felt great last week but now when i have a 2 p.m coffee you know what i'm not quite as good okay that's that's gonna teach me now that i'm gonna i'm gonna knock it a bit earlier in the day because i think ultimately nobody's going to follow

your advice or my advice simply because we told them to. I think it's only when they start to feel the difference themselves, they go, wow, you know, I kind of like feeling good. Yeah. And I think, you know, I love your point about just trying to give it time to, you know, sleep and starting to change your sleep and seeing the effects of getting better sleep. It's a little bit like exercise at the gym. You know, you're not going to go to the gym one day and wake up looking like Arnold Schwarzenegger. You know, it just takes some time. But if you commit to it, you will see gradual change. And it's the same thing with sleep as well. But I also think I love the idea of you, you know, putting sleep in that bedrock place and then starting to introduce the other factors.

What's lovely is that many of them will actually fall in place when sleep is stabilized. And I'll give you a good example of diet. We know that without sufficient sleep, two critical appetite hormones go in opposite bad directions. One of those hormones is called leptin, which is a hormone that sort of signals to your body, you're full, you don't want to eat anymore. The other hormone is called ghrelin, which does the opposite. It says you're not satisfied with your body, you're full, you don't want to eat anymore. The other hormone is called ghrelin, which does the opposite. It says you're not satisfied with your food, you want to eat more. And despite leptin and ghrelin sounding like two hobbits, they are actually real hormones. What's interesting is that when you sleep deprive people, or even just limit them to maybe just like

five or six hours of sleep for a week, levels of leptin, which say you're full, don't eat more, they drop down. Levels of ghrelin that ramp up your hunger and say, I've just eaten a big meal, but I'm not satisfied. I want to eat more. That hormone skyrockets when you're underslept. So no wonder people who are sleeping just five to six hours a night will actually eat on average somewhere between 200 to 300 extra calories every single day. So you can solve sleep and you will actually start to not want to eat as much. Yeah. And this is why a part of weight loss is to sleep better. It's a critical factor. And I think

next time I get you on, Matthew, we'll probably go into detail on that. We'll probably go into detail on Alzheimer's and maybe even things like menopausal symptoms and hormonal symptoms that I also see sleep deprivation playing a huge role in. I know you're on a really busy schedule. That's how it is when you have such a popular international bestselling book. And you know all about that too. Well, guys, I'd highly encourage you to pick up Matthew's book, Why We Sleep. It's absolutely brilliant. It's got pretty much everything you've ever wanted to know about sleep. I think you'll probably find in that book. I look forward to when you release a later edition,

when you've got newer research coming out in the future at some point. But Matthew, one question I like to ask my guests who are leading researchers in the field is, as you became more and more aware of all this sleep research, what was the biggest thing in your own lifestyle that you changed on the back of your research? I think it was probably caffeine. I think just seeing the data and then doing those types of studies ourselves and particularly the finding that we discussed

were even if you're asleep, the quality of that sleep is just not as deep. That really got me concerned. And that's when I really started to pay attention to my caffeine content. Are you teeter-to-nower caffeine or are you? So right now, yeah, I am. I drink decaffeinated tea and I drink decaffeinated coffee. I sometimes, you know, I've ebbed and flowed between sort of having coffee in the morning because I do feel it's alerting benefits. But, you know, we didn't necessarily evolve to be medicated with caffeine. And I think anyone who's, you know, drinking caffeine at 11 a.m., which on the basis of your circadian rhythm, if you listen to the wonderful podcast with

Sachin Panda that you did, you know, your peak of your circadian rhythm is right around sort of the 11 o'clock period. That's when it should be almost impossible for you to fall asleep. But yet, you know, I sometimes look around on an airplane when I'm leaving and people, half the plane is asleep at 11 o'clock. And if you're self-medicating your sleep deprivation at 11 a.m. with caffeine, it usually means that you're perhaps just not getting enough sleep. And that's probably been one of the greatest, I think, influential factors. That and the impact on my productivity, I think that was the most underrated. And it actually forced me to start doing a lot of research on sleep loss and productivity that maybe on a second podcast we can talk about. What we can get into, yeah. But, you know, my ability to maintain focus and produce high quality output work

is dramatically dependent on the sleep that I've been having at night. That absolutely echoes what Professor Panda said a few weeks ago on this podcast. When he goes off caffeine, his productivity goes up. So guys, look, no one's asking you guys to cut out caffeine. I know how much you guys love it. I have certainly had my own love-hate relationship, well, more love of a relationship with coffee in the past, but I have dramatically reduced it,

and I'm feeling better than I've ever felt. Matthew, I really want to thank you for the time you've made today to come onto the show, to really talk to my listeners who really are big fans of your work, really are looking for those actual bits of information that they can take into their lives. So I want to thank you for that.

I absolutely will take you up on your promise. I'm going to call it a promise to come back on the podcast. It is a promise. Guys, I hope you've enjoyed today's podcast from Matthew and myself. Thank you. Take care and sleep well, everyone.

That concludes today's episode of the Feel Better Live More podcast. What did you think? Have you been motivated into putting sleep at the top of your priority list? I know for me that when I started really prioritizing my sleep health a few years ago, the knock-on benefits were immense. As always, try and think about one thing that you can take from this podcast to apply into your own life, even if it is simply the acknowledgement that sleep should become a higher priority than it already is. I know we spent a lot of time talking about the impacts of sleep deprivation today. If you want some practical tips on how to improve your sleep, I would highly encourage you to check out my first book, The Four Pillar Plan, which has a whole section on sleep and it's full of practical tips that really do work.

Many of you have fed back to me that this book has transformed your sleep health. So if you do not have a copy yet, please do check it out. Just a quick note that the same book is available in the US and Canada with a different title, How to Make Disease Disappear. Don't forget guys that Calm are sponsoring today's show. They have lots of resources for sleep, including their infamous sleep stories. Listeners of this podcast get 25% off a Calm premium subscription at calm.com forward slash live more. So if you have been sitting on the fence about meditation, or if you want to try Calm as a way of improving your sleep health, this could be a great way to get you started.

Do let Matthew and I know what you thought of today's show. Matthew is active on Twitter at Sleep Diplomat, and I'm on Twitter at DrChatterUK and on Facebook and Instagram at DrChatterG. Please do use the hashtag FBLM if you can when posting. The show notes section for today's episode is really comprehensive. You can find them at DrChatterG.com forward slash 70, that's seven zero. There are loads of links, articles, blogs, all about sleep so that you can continue your learning experience now that the podcast is over. Don't forget also that Matthew has agreed to do a follow-up podcast with me to answer any

questions on sleep that were not covered today. Head over to my brand new Facebook group, Dr. Chastity, four pillar community tribe to my brand new Facebook group, Dr. Chatterjee Four Pillar Community Tribe to let me know what questions you have and I will get them answered by Matthew as quickly as I can. A lack of sleep is one of the biggest stresses on our body and stress is responsible for up to 90% of what a GP like me sees in any given day.

This is the reason why I wrote my latest book, The Stress Solution, to help you manage your stress so that you can live a happier and calmer life. This book has had over 150 reviews so far on Amazon with an incredible average rating of 4.9 out of five. If you feel that you would benefit or that you know someone who might,

please do pick up a copy. It is available on paperback, ebook, and as an audiobook, which I am narrating. If you enjoy my weekly shows, please do consider supporting them by leaving a review on Apple Podcasts or whichever platform you listen to podcasts on. You can also help me spread the word by taking a screenshot right now and sharing with your friends and family on your social media channels or you can do it the old-fashioned way and simply tell your friends about the show your support is very much appreciated one more request i am feeling a little bit overloaded at the moment with the amount that i've got on and so i'm looking to expand my team so that I can keep producing content

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That is it for today. I hope you have a fabulous week. Make sure that you have pressed subscribe and I'll be back in one week's time with my latest episode. Remember, you are the architect of your own health. Making lifestyle changes always worth it. Because when you feel better, you live more. I'll see you next time