Why We Sleep with Matthew Walker PART 1 | Feel Better Live More Podcast

Dr. Rangan Chatterjee 0:00 [upbeat music]

Dr. Rangan Chatterjee 0:00 Hi, my name is Dr. Rangan Chatterjee, medical doctor, author of The 4 Pillar Plan, and television presenter. 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. For today's episode of the Feel Better Live More podcast, I'm absolutely delighted that I've got the opportunity to interview my next guest. He is one of the world's leading sleep researchers, and he's author of the absolutely fantastic book, the international bestseller, Why We Sleep. It's Professor Matthew Walker. Matthew, welcome to the podcast.

Matthew Walker 1:06 Thank you so much for having me. It's a delight to be chatting again. Lovely.

Dr. Rangan Chatterjee 1:09 Yeah, Matt, we, obviously we, we sort of first had contact over email, um, and we got to do a Facebook Live conversation on my Facebook page, which proved a huge hit, uh, 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.

Matthew Walker 1:34 It's lovely to finally meet you in person, Rangan.

Dr. Rangan Chatterjee 1:37 Yeah, it's, it, it's superb. But I thought we might start just by asking you, how many days have you been in London now for?

Matthew Walker 1:46 Um, I arrived on Saturday, so this is my fourth day.

Dr. Rangan Chatterjee 1:50 Your fourth day. So look, at the moment it's about, well, we've probably just gone past 11:00 AM in the UK, which probably means, I'm guessing it's about 3:00 AM in San Francisco.

Matthew Walker 2:03 [laughs]

Dr. Rangan Chatterjee 2:03 So what's going on with your body clock at the moment?

Matthew Walker 2:06 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

Matthew Walker 2:37 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. So whenever you arrive, and then for all of the days afterwards, make sure that you get about twenty to thirty minutes of natural daylight. 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, even if it looks, [laughs] you know, you look fantastic and you look very cool-

Dr. Rangan Chatterjee 3:28 [laughs]

Matthew Walker 3:28 ... 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. 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 you, 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, um, 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 wear 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. Um, the only other trick I would say is during traveling. I see a lot of people make the mistake of

Matthew Walker 4:59 when they sleep during travel. It's very natural. If I'm flying over from San Francisco, um, to London, usually leave around 5:00 PM in the evening.

Dr. Rangan Chatterjee 5:09 Yeah.

Matthew Walker 5:09 Most people, and let's say it's an eleven-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 eleven o'clock in the morning London time. That's not the ideal thing to do. Try to sleep on your flight either in, early in the flight or in the middle of the flight. And the rule of thumb is make sure that whatever time of, uh, you want to go to bed in the new time zone that evening, let's say it's, you know, ten o'clock, count back at least twelve hours or ten hours. That's the time that you have to wake up on the plane and then stay awake.

Dr. Rangan Chatterjee 5:48 Yeah.

Matthew Walker 5:48 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 forgo sleep, which sounds strange from-

Dr. Rangan Chatterjee 6:03 Wow

Matthew Walker 6:04 ... someone like me. Push through for the rest of the day and then just get to bed early and you'll get into set.

Dr. Rangan Chatterjee 6:09 So thanks for sharing those tips, um, 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. Um, so we'll get into that in just, just a, a, a few moments. I actually... I'm, I'm 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 gotta 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've been morning in California, I took off my night shades. I did not put on my blue light blockers, and I actually watched a film. So I was exposing myself to blue light from-

Matthew Walker 7:27 Yeah

Dr. Rangan Chatterjee 7:28 ... my screen-

Matthew Walker 7:28 Yeah

Dr. Rangan Chatterjee 7:28 ... 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, the n- 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, um, in the new time zone with a bit of a headache 'cause my body was expecting caffeine earlier. It didn't have it, and I th- think that that was artificially waking me up.

Matthew Walker 7:59 Yeah.

Dr. Rangan Chatterjee 7:59 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, you know, start off this conversation on a downer.

Matthew Walker 8:09 [laughs]

Dr. Rangan Chatterjee 8:10 But, you know, let's go into caffeine. I mean, how much of a sleep disruptor is caffeine?

Matthew Walker 8:14 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, th- they serve caffeine liberally.

Dr. Rangan Chatterjee 8:28 Yeah. [laughs]

Matthew Walker 8:29 And the other thing they serve is alcohol, and 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, uh, make it much harder for your 24-hour biological circadian clock to readjust. Both of those will, will actually take away those fingers on the wristwatch and sort of, or slow the progression down. Um, but caffeine is a misunderstood drug. Certainly m- everyone-

Dr. Rangan Chatterjee 8:54 It's a drug, right? You use the term drug-

Matthew Walker 8:56 It is-

Dr. Rangan Chatterjee 8:56 ... and that's interesting.

Matthew Walker 8:57 It is a drug. Um, it's what we call a psychoactive stimulant. Um, everyone knows that caffeine can help alert you and sort of keep you awake. That's the thing that's most known. Um, 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 [laughs] about-

Dr. Rangan Chatterjee 9:16 Wow

Matthew Walker 9:16 ... 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.

Dr. Rangan Chatterjee 10:01 Wow.

Matthew Walker 10:01 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. It... You know, you would never do that-

Dr. Rangan Chatterjee 10:14 Yeah

Matthew Walker 10:14 ... 'cause you know. But that's exactly, unfortunately, what people do, you know, um, completely innocently by drinking caffeine, you know, still too late in the afternoon.

Dr. Rangan Chatterjee 10:23 Yeah, it's a, it's a, it's a huge problem.

Matthew Walker 10:25 It, it's, it's a m- I, I think it's a big problem in society if you... I mean, another way [laughs] 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 [laughs] for, 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.

Dr. Rangan Chatterjee 10:45 And well, cafe culture is just growing at, you know, exponentially now.

Matthew Walker 10:49 Yeah.

Dr. Rangan Chatterjee 10:49 Right? It's the new... You know, I, I talk about sometimes it's almost like a new, new pub culture. It's cafe culture.

Matthew Walker 10:55 Yeah.

Dr. Rangan Chatterjee 10:55 You know, you hang out with your friends. You meet up. You get your drink. Typically, it'll be a caffeinated drink.

Matthew Walker 11:00 Yeah.

Dr. Rangan Chatterjee 11:00 Um, we've now got school kids. You know, I saw in a local village I was walking through recently, you know, after school, you know, I popped into a cafe to get, I think, a, a bottle of water. Uh, I can't actually remember, but I, I popped in, and I saw a group of school kids. They must've been maybe 13 or 14. After school, they're sitting in the cafe with their caffeinated drinks, you know, 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, 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. Chatterjee, 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.

Matthew Walker 11:59 Yeah.

Dr. Rangan Chatterjee 11:59 And, um, uh, and you know, Satchin Panda, um, 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, he will have a bit of a detox from caffeine. He'll go off caffeine. And he says, "When I do that, yeah, 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.

Matthew Walker 12:26 It does. And I, I, 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. Um, I think the, the second point comes onto 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 two hundred 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, um, uh, all of our brain during 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 twenty percent. Now, you would have to normally age by about fifteen 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 'cause 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. They-

Dr. Rangan Chatterjee 13:59 I need more caffeine. [laughs]

Matthew Walker 13:59 And, 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, 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.

Dr. Rangan Chatterjee 14:25 Well, I think, you know, you raised a really important point there, Matthew, about, you know, knowledge and awareness. You know, none of us are pointing fingers. You know, we-

Matthew Walker 14:35 Yeah

Dr. Rangan Chatterjee 14:36 ... you know, I understand caffeine is everywhere. You know, I probably used to over-drink caffeine. Uh, and I've altered my behavior 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, 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 i-in my book is enjoy your caffeine before noon. And I say enjoy 'cause I get it. Uh, people love it. Why, I love a good cup of coffee, but I will not have caffeine after midday.

Matthew Walker 15:25 Yeah. And I, you know, I've now actually done what Sachin has done. I, I would... I routinely go through sort of a caffeine detox. Um, 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, um, Yorkshire tea - uh, I have no relationship with them, by the way [laughs] -

Dr. Rangan Chatterjee 15:44 [laughs]

Matthew Walker 15:45 ... um, in the mornings. And I also love the, 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, I want people to embrace it 'cause I think it's fantastic that there's a social movement sort of circulating around that. Um, all I would say, though, is that, you know, decaf-decaffeinated coffee is, is actually really quite good. And I would strictly... I'd love to do the sort of the, you know, the Coke-Pepsi challenge with decaf and caffeinated. 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'll probably know the difference. But I've really become enamored with decaffeinated coffee-

Dr. Rangan Chatterjee 16:23 Wow

Matthew Walker 16:23 ... and all of its flavors. And I love the cafe bar culture, so love to embrace that. But I do like what you're saying, uh, about sort of patients just thinking a little bit about caffeine and considering it and just trying the, try the experiment. You know, sort of set yourself the task, give it a go, and see if it works for you.

Dr. Rangan Chatterjee 16:41 Yeah. I, I remember about a month after my book came out, uh, someone tweeted me and said, "I, I never, ever thought that caffeine was a problem for me, but I've, I've read your book. I've taken your recommendation. I've, I've, how... I now only have two cups of coffee, and I have it before noon, and I've never slept this well in over thirty 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, and it just continues. I think we also have to highlight, we're talking about coffee, but I think tea-

Matthew Walker 17:21 Yeah

Dr. Rangan Chatterjee 17:21 ... w-would be similar 'cause it contains caffeine. Green tea, you know, 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 are saying that decaf coffee does contain some caffeine. Do you know much about that?

Matthew Walker 17:40 Yeah. So decaffeinated coffee is not no-caffeinated coffee. [laughs] So you do have to be, uh, you know, somewhat mindful of that. Um, 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. Um, other brands, however, I was surprised to find can have up to twenty percent, uh, 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. Um, 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, you know-

Dr. Rangan Chatterjee 18:17 Exactly

Matthew Walker 18:18 ... pleasure. Um-

Dr. Rangan Chatterjee 18:18 And, and it tastes great, right?

Matthew Walker 18:20 Yeah. It does.

Dr. Rangan Chatterjee 18:20 [laughs]

Matthew Walker 18:20 It, it really, it, it, it's not too bad.

Dr. Rangan Chatterjee 18:23 So caffeine is something that a lot of us do in the morning. Um, we're also gonna 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, 'cause I think that's something that people are incredibly fascinated about, 'cause I think that whole term of the nightcap, you know, people-

Matthew Walker 18:43 [laughs]

Dr. Rangan Chatterjee 18:44 ... it's there in, in our vernacular now, how it's something that can help you just slip off into sleep. Or can it? We'll fi- we'll find out shortly.

Matthew Walker 18:51 [laughs]

Dr. Rangan Chatterjee 18:51 But, you know, listeners to my podcast know that I, 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.

Matthew Walker 19:04 Mm.

Dr. Rangan Chatterjee 19:04 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.

Matthew Walker 19:22 Yeah. You know, 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. Um, 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, um, 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-

Dr. Rangan Chatterjee 20:00 Wow

Matthew Walker 20:00 ... 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, 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, uh, 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.

Dr. Rangan Chatterjee 21:10 Wow.

Matthew Walker 21:10 What's even more frightening, however, is that your risk for injury increases when you are exercising but not well-slept.

Dr. Rangan Chatterjee 21:18 This is incredible.

Matthew Walker 21:18 And they did this great study where they looked at, um, 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, and 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.

Dr. Rangan Chatterjee 22:02 Yeah.

Matthew Walker 22:03 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.

Dr. Rangan Chatterjee 22:24 I am seeing that a lot as well, you know, and I, I have experienced that myself in terms of, squash is one of my favorite games, um, but if I play squash at about 7:00 or 7:30 PM, I can't sleep that night. You know, I'm lying in bed at night. Um, I know it's about 5:00-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, I'm seeing that a lot with patients, which again, you know, if people are after work, they're trying to fit their workouts 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.

Matthew Walker 23:07 Yeah.

Dr. Rangan Chatterjee 23:07 But, but I see that a lot, working out intensely in the evening is a problem. Have you done research on that in your lab?

Matthew Walker 23:13 So we've looked at this with body temperature, too, you know, and, and I understand that people... You know, I still want to celebrate and embrace the idea of people exercising.

Dr. Rangan Chatterjee 23:21 Of course.

Matthew Walker 23:21 I think that's critical. Um, and even if it's late into the night, best not to do that, but if you do do that, a good way, um, to try and solve the higher core body temperature is to have a bath or a shower right before bed. And-

Dr. Rangan Chatterjee 23:36 A hot bath, right?

Matthew Walker 23:37 A hot bath is best-

Dr. Rangan Chatterjee 23:38 Yeah

Matthew Walker 23:38 ... 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 al- the reason that it's always easier to fall asleep in a room that's too cold than 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.

Dr. Rangan Chatterjee 24:14 It's a great tip, though, for people, 'cause 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, 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, you know, you know, as a sportsman myself, I sort of, you know, this really, you know, 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, uh, may know mor- more about this, but I have heard that Roger Federer may get... I think he's been on record say he gets 12 hours of sleep a night. I don't know if that's true or not. Have, have you heard a- about that at all?

Matthew Walker 24:58 Yeah, yeah. So he does. He gets about, uh, 12 hours of sleep, and if you look at lots of sports athletes, um, 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 nine to 10 hours at night. Um, Usain Bolt, you know, he is, um, he says he never gets anything less than nine hours, and I believe w- for one of his world records, um, he had only been awake for about, uh, 35 minutes 'cause he'd taken a nap [laughs]

Dr. Rangan Chatterjee 25:35 Oh, love it

Matthew Walker 25:35 ... right before, I think it was an Olympic gold and a world record that he broke, and, uh, 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, um, some, uh, Premier League football teams as well as NBA, NFL in the United States 'cause they're starting to, 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, uh, 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, um, not recognizing what they can do with sleep.

Dr. Rangan Chatterjee 26:17 Yeah.

Matthew Walker 26:17 They l- front-load it 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 just, uh, I say it just for people who are, you know, really interested in being physically active, maintaining their peak performance. Make sure that you also consider sleep after being physically active as well.

Dr. Rangan Chatterjee 26:58 When, when we talk about peak performance, you know, 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, 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 under-slept and tired.

Matthew Walker 27:28 Yeah.

Dr. Rangan Chatterjee 27:28 They wanna get to work and perform well in their jobs, 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, you know, Roger Federer, LeBron James, you know, yeah, for 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 prioritize sleep? How much sleep do we need every day? But also, in episode 14 of this, this podcast, it was a few episodes ago, I interviewed, uh, Nick Littlehales, um, who for, you know, many years has been advising clubs like Manchester United, uh, 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, with-

Matthew Walker 28:19 Yeah

Dr. Rangan Chatterjee 28:20 ... this recommendation.

Matthew Walker 28:20 Yeah.

Dr. Rangan Chatterjee 28:20 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 try and-

Matthew Walker 28:33 Yeah

Dr. Rangan Chatterjee 28:33 ... just try and go into those, those areas a little bit.

Matthew Walker 28:36 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, you know, 11:00 PM and I wake up at 6:00 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, and that's, 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, 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, um, 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."

Dr. Rangan Chatterjee 29:43 [laughs] Yeah.

Matthew Walker 29:43 And you say, "No, I know that you think you f- 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, um, one of the issues that, um, I try to sort of help dismiss, uh, 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." And people don't realize that if you were 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.

Dr. Rangan Chatterjee 30:35 Yeah, absolutely.

Matthew Walker 30:36 It just requires perhaps, you know, some knowledge and an invitation to go there.

Dr. Rangan Chatterjee 30:40 Matthew, I c- I call this podcast Feel Better, Live More. For a reason, and it, it really just echoes what you, what you just said then. You know, when we feel better by, you know, prioritizing sleep, by, you know, looking at these other pillars that I talk about, we get more out of life. We're, 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.

Matthew Walker 31:10 We do. I mean, firstly, that data is very clear that, um, 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.

Dr. Rangan Chatterjee 31:25 Wow.

Matthew Walker 31:26 And so, you know, I think that-

Dr. Rangan Chatterjee 31:27 I think we just need to stop and just let, let that sink in for a minute.

Matthew Walker 31:30 [laughs]

Dr. Rangan Chatterjee 31:30 Depriving ourselves from sleep will shorten our life.

Matthew Walker 31:34 Yeah.

Dr. Rangan Chatterjee 31:35 Yeah, I mean-

Matthew Walker 31:35 That's the, the, 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, um, in the 21st century, it is a slow form of self-euthanasia.

Dr. Rangan Chatterjee 31:51 That'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?

Matthew Walker 32:09 Yeah, it's a, it's a great question. I've thought about this a lot. Um, 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'd liken where we are with sleep with where we were, um, for smoking 50 years ago. You know, all of the science was there, but it hadn't trickled down-

Dr. Rangan Chatterjee 32:54 Yeah

Matthew Walker 32:54 ... into the public knowledge base or even into medicine.

Dr. Rangan Chatterjee 32:57 Well, that's what you did so great with your book, is you're, you're bringing that awareness to the general public all over the world, which is fantastic.

Matthew Walker 33:03 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, um, there wasn't a blueprint guide. There wasn't some kind of a, a manifesto for sleep, and so that was part of the reason to write the book. But I think to come back, um, 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. Um, 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, 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, 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.

Dr. Rangan Chatterjee 34:18 Yeah.

Matthew Walker 34:18 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, 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, uh, in a way, too. I think those are at least two of the reasons why it's been left out in the cold.

Dr. Rangan Chatterjee 34:56 Yeah. Yeah, absolutely. I mean, I, you know, I've shared this before on the podcast, that a few years ago, for, for me, it was probably when I had kids, actually, because my kids were early risers, and, you know, that's, that's the understatement [laughs] of the year-

Matthew Walker 35:12 [laughs]

Dr. Rangan Chatterjee 35:12 ... that they were early risers. But I realized that if I didn't alter my going to bedtime, I was gonna be exhausted every single day, which is what was happening. And I, and I sort of altered my whole sleep schedule a few years back, and it's something now that I really do prioritize. You know, I will have a shutoff time in the evening, after which I'm not on my computer. I'm not working. I will wait 'cause I know that if I don't do that, the next day I won't be performing at anywhere near the level I want to. Um, and, and it [laughs] actually reminds me of that, that Facebook conversation we had, the Facebook Live chat we did.

Matthew Walker 35:47 Yeah.

Dr. Rangan Chatterjee 35:47 So guys, we were trying to schedule this chat for a little while, and-

Matthew Walker 35:50 Oh, I love this. Yeah

Dr. Rangan Chatterjee 35:51 ... we, we, we put a date in, and then, uh, Matthew had to move, 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 9:00 PM UK time. Man, that's really late," because, you know, I've just, I've just written a book saying how important sleep is as well. I'm, I'm, you know, 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 at 9:00 PM.

Matthew Walker 36:17 Well, I just actually asked to see if we could change the time.

Dr. Rangan Chatterjee 36:19 Yeah, you probably didn't know.

Matthew Walker 36:20 Yeah, I certainly wouldn't have suggested the-

Dr. Rangan Chatterjee 36:21 Yeah, I said, "Guys, look, if we chat between 9:00 and 10:00, and we talk about how detrimental sleep is, and, you know, uh, you know, and, and, and all the problems associated with it, yet we're doing it late in the evening for my UK audience, um, we're ex- I'm gonna expose everyone to blue light in the evening-

Matthew Walker 36:38 [laughs]

Dr. Rangan Chatterjee 36:38 ... right on, 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, that was quite nice.

Matthew Walker 36:47 That was brilliant.

Dr. Rangan Chatterjee 36:47 Yeah, that was great, wasn't it, though?

Matthew Walker 36:48 Yeah, it was just, you know, for someone to embrace, you know, sort of, uh, and practice what they preach. And, you know, and I think for the two of us, you know- But 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 n- 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, um, 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, a shorter life that is filled with, with disease or sickness. And from everything I can tell, sleep is perhaps one of the most democratic, freely available, efficacious forms of, um, 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. Um, and one of the things I actually g- if I, if you don't mind, [laughs] I know y- this is your podcast and you're interviewing me, but-

Dr. Rangan Chatterjee 38:13 Hey, Matthew, talk about whatever you want. Fire away

Matthew Walker 38:15 But, but I, but I would love to just ask you the question 'cause, you know, when I saw the title of, of the book, you know, and I saw that, you know, there on the front cover was this word called sleep, and it was-

Dr. Rangan Chatterjee 38:25 On, on my book?

Matthew Walker 38:26 On your, on the-

Dr. Rangan Chatterjee 38:26 Yeah, yeah

Matthew Walker 38:27 ... on the front cover of your book-

Dr. Rangan Chatterjee 38:28 Yeah

Matthew Walker 38:28 ... 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, a, an eminent clinician, but I was surprised by the, the fourth. I was ex- lovely, excited. You know-

Dr. Rangan Chatterjee 38:43 [laughs]

Matthew Walker 38:43 ... it was wonderful. But tell me, you know, w- 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 personally? Tell me. I, I'd love to know.

Dr. Rangan Chatterjee 39:01 Yeah, I think, Matthew, that's a, that's a great question, really. I mean, my... I guess my journey into this, um, of, of really being keen to promote lifestyle comes from a, you know, a, a real feeling that in medicine we've lost our way a little bit. Now, we're not putting blame on anyone.

Matthew Walker 39:18 Yeah, yeah.

Dr. Rangan Chatterjee 39:19 Um, but I, but I sort of feel that 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, 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.

Matthew Walker 39:52 Hmm.

Dr. Rangan Chatterjee 39:53 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?

Matthew Walker 40:07 [laughs]

Dr. Rangan Chatterjee 40:07 You know? It was like, okay, you know, it's all about diet, you know? And if we were having this chat five or six years ago, I would be saying, you know, most of what happens to us, you know, w- most of our health determinant is, is basically foods. But I disagree now, you know, because I think when you know the science, when you have seen the science, um, as you detail so beautifully in your book, the, 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. So I want to go upstream as far as possible to see what lever can I turn that's gonna 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 kind of things. And, you know, so obviously, um, that's food. That's movement. Relaxation is a whole piece about stress. You know, which, you know, some research is showing that nine- up to 90% of what we see in primary care may have stress as a factor, which is incredible. And but I always felt I was missing one piece of the puzzle, and-

Matthew Walker 41:29 Hmm

Dr. Rangan Chatterjee 41:29 ... you know, I would see, like, like if we take autoimmune disease for, for an e- as, as an example, when I see my patients, I often do what's called a timeline, and I look... You know, 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," 'cause 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, you know, just a few months, sometimes just one month before the onset of symptoms, I would see either a, either... You know, well, not either. I would often see a really stressful episode happen that would reduce the quality of people's sleep, and then I'd see symptoms come on.

Matthew Walker 42:13 Yeah.

Dr. Rangan Chatterjee 42:13 And as 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 of 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, uh, San Diego about two years ago, and the whole conference was on sleep and relaxation and, and rest and, and I think it was, uh, Phyllis Zee. Do you know Phyllis?

Matthew Walker 42:57 Phyllis Zee? Yeah.

Dr. Rangan Chatterjee 42:58 Yeah, Phyllis Zee.

Matthew Walker 42:59 Yeah, yeah, yeah, yeah.

Dr. Rangan Chatterjee 42:59 She gave a couple of keynotes there, and I thought, "God, this really is whetting 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, that is to empower people to take control of their health and not cover sleep?" You know, I can't do it.

Matthew Walker 43:19 [laughs]

Dr. Rangan Chatterjee 43:19 I, I just, you know, I can't, I just can't do it.

Matthew Walker 43:21 What was so, 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-

Dr. Rangan Chatterjee 43:28 Yeah

Matthew Walker 43:28 ... you know, that you, you know, through your own sheer interest and desire to try and help-

Dr. Rangan Chatterjee 43:32 My own money, my own sort of annual leave to go and do this stuff-

Matthew Walker 43:35 Yeah, yeah

Dr. Rangan Chatterjee 43:35 ... 'cause I'm interested.

Matthew Walker 43:36 That's where you got your sleep education. And, you know, that, that strikes me as, as so, you know, unfortunate. I, 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 know, have lots of friends here who are, 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, you know, it's like the Archimedes lever. You pull that, everything else-

Dr. Rangan Chatterjee 44:33 Yes

Matthew Walker 44:33 ... you know, can start to come into play.

Dr. Rangan Chatterjee 44:34 Yeah, the s- you get the sleep, but it affects your brain, it affects your hormones, it affects your genetic expression. It affects-

Matthew Walker 44:39 Yeah

Dr. Rangan Chatterjee 44:39 ... 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-

Matthew Walker 44:46 By-

Dr. Rangan Chatterjee 44:46 ... by improving your sleep.

Matthew Walker 44:47 Yeah, you know, and it's no, we, 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, uh, 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? [upbeat music]

Dr. Rangan Chatterjee 45:26 That concludes today's episode of the Feel Better Live More Podcast. Remember, this is only part one of a two-part conversation. In next week's episode, you can hear the rest of my conversation with Professor Walker. And if you enjoyed today's episode, I think you are gonna absolutely love next week because next week, Matthew talks about how sleep is the Swiss Army knife of health, so whatever ailment you are facing, sleep is gonna help you. He talks about medical school training and how we don't really learn as doctors about sleep science. He talks about how society is bathed in electric lights and the implications on our health and on our sleep. He talks about caffeine, alcohol. He talks about how sleep deprivation can cause you to eat 200 to 300 calories extra every single day. And we finish off with Matthew telling you what he has changed in his own life since he got into sleep research. It's absolutely incredible. There's loads of great stuff coming up. So guys, I'd really encourage you to press Subscribe. Whatever podcast platform you're listening to this on now, if you press Subscribe, you will be notified as soon as the next episode comes out. Guys, everything that Matthew and I spoke about will be available on the show notes page on my website at drchatterjee.com/matthewwalker. So do take a look so that you can continue your learning experience now that the podcast is over. There's plenty of links, plenty of articles that Matthew has written that you can access from the show notes page. So that's drchatterjee.com/matthewwalker. Remember, sleep deprivation is a big stressor on our body, and it's one of the many things I cover in my brand-new book that comes out in just a few months now, The Stress Solution: Four Steps to Reset Your Body, Mind, Relationships, and Purpose. I'm really, really excited about the new book. I think it's gonna help a lot of people manage their stress levels and get them under control. And the book is now available to pre-order from Amazon, so if you search The Stress Solution on Amazon, or just go to the show notes page, you can get a link to the book straight there. If you are listening to this in the USA or Canada, my book The 4 Pillar Plan has come out there about a month ago, but it's got a brand-new title there, and it's called How to Make Disease Disappear. Again, you will get a link to that on the show notes page, or you can just Google it and, uh, find it at one of your local bookstores. Guys, if you wanna support this podcast, which I, I really hope you do, it's actually pretty simple to do so. You can just share this episode with a friend or with a family member, or take a screenshot and put it on social media, on Instagram, Insta Stories, Facebook, Twitter. Do tag me. Do tag my guests. When you do this, it helps me interact with you. You can also press Subscribe, which is a great way for me to raise the profile of the podcast. And if you haven't already, I'd be so grateful if you go onto your podcast platform and give this a five-star review. It helps raise the profile of the podcast, which means I, in turn, can hope to attract better guests for you in the future. And finally, thank you so much for listening to the podcast today. I hope you enjoyed it, and I hope you can join me next week when the very next conversation on my podcast comes out. [upbeat music]