126: Matthew Walker | Unlocking the Power of Sleep and Dreams

Transcript for Matthew Walker | Unlocking the Power of Sleep and Dreams (Episode 126)

Jordan Harbinger: [00:00:00] Welcome to the show. I'm Jordan Harbinger. As always, I'm here with my producer, Jason DeFillippo. A lot of us, whether we're entrepreneurs or nine to fivers, we want to optimize our sleep, or just get more or better sleep. There's been a lot of talk about sleep hacks in the business and health community lately, but much of it has been pseudo-science and not come from the people who are actually doing the research that changes now. Today, we're talking with my friend Matthew Walker. He's a scientist and professor of neuroscience and psychology at the University of California Berkeley, and his research focuses on the impact of sleep on human health and disease. He also doesn't seem to be aging all that much because he looks like 20 something, so perhaps there really is something that is whole sleep thing and that is what we're going to discuss today.

[00:00:44] First, we're going to scare the crap out of everyone by talking about what happens when you don't get enough sleep. I know! Most of us just have to look in the mirror to see those effects, but it's actually far worse than it seems, and I want you to get a full grasp of what sleep does for us and how we can make sure we're getting enough of it. After our Deep Dive on sleep and health, you're going to learn the answers to some questions we've all got about sleep, such as why do I wake up right before my alarm? What's going on in my dreams and what do they mean? What does lucid dreaming and how come sometimes I can control what I'm dreaming about? You all know me, I'm full of weird questions and I've dialed in on Matthew today to get some interesting nuggets that you can use to improve your sleep as well as your understanding of your own sleep.

[00:01:24] And finally, we'll talk about how we can use sleep and sleep management to learn better, make more memories and skills sink in more effectively and avoid some common misconceptions that almost everyone has about their own sleep. This was an absolutely fascinating interview and I could have gone on for hours. There's just so much practical information in here that we can all use to improve our sleep and improve the health of our brains and bodies. Now, here's Matthew Walker.

[00:01:51] Matt, I've actually, this might sound a little weird, but I think there's probably something to this. I think what's disturbing my sleep the most is the fact that I'm trying to track my sleep. Is that makes sense?

Matthew Walker: [00:02:01] It does. And there is an emerging clinical disorder and a name for that. It's called—

Jordan Harbinger: [00:02:06] Oh good, I've got  a new disorder. Tell me all about it.

Matthew Walker: [00:02:08] Yeah, it's called Orthosomnia. So ortho simply means straightening. So you've heard of sort of orthopedics, for example, but sort of keeping bones straight. And so this is about people who are too fixated on getting their sleep right or getting it straight as it were. And so much so that you become — and I'm like this too because I'm a sleep scientist, I know too much about sleep. So you become the Woody Allen neurotic of the sleep world.

Jordan Harbinger: [00:02:38] Yeah.

Matthew Walker: [00:02:38] And you get so I think anxious and sometimes competitive both with yourself and other people if you've got a tracking competition, I've heard people do doing this. So there is an emerging disorder. Is it a tiny fraction of the population? I think it is.

Jordan Harbinger: [00:02:56] Well sure.

Matthew Walker: [00:02:57] I think most people are in danger of probably underestimating the importance of sleep and not paying enough attention. There are a few people who take it to it via extremes. We will always see that bell curve distribution. We'll always see the extreme edge cases.

Jordan Harbinger: [00:03:09] Nothing keeps me up at night, like worrying about how much sleep I'm getting or not getting. I'll tell you that.

Matthew Walker: [00:03:13] Well, that was the funny thing with the book. I think I wanted to — I'd done enough public lectures out there in the world that I started off speaking about the wonderfully good things and amazing things that happen when you get sleep and people thought, "That's great. That's really fascinating." But then they never had behavioral change, then I switched to actually speaking about the demonstrably and frighteningly bad things that happen when you don't get enough sleep. That's when people really start to sit up and pay attention. So I think the book was sort of biased towards, maybe it wasn't scaremongering because I don't overemphasize, I don't exaggerate the science.

Jordan Harbinger: [00:03:51] No, it's actually just real scary.

Matthew Walker: [00:03:52] Sort of just hardship.

Jordan Harbinger: [00:03:53] Yeah.

Matthew Walker: [00:03:54] But it's just simply frightening, the science behind insufficient sleep. And I did get a few reviews and I did get a few people write to me to say, it was so frightening that it's actually now keeping me up at night doing the opposite. And I thought, "Oh no."

Jordan Harbinger: [00:04:09] Try hitting yourself in the head with the book until you fall asleep.

Matthew Walker: [00:04:12] I wish I was so bold to offer a suggestion like that.

Jordan Harbinger: [00:04:15] But it is scary because we see how easy it is to fall behind on sleep and then end up cognitively impaired, and some of the examples you give in the book are like, "Hey, if you haven't slept for 16 hours," or whatever, which is like a normal day, and then you try to drive and it could be 20 hours, you're the expert here, so correct me where I'm wrong. You're basically driving after having drank enough to be considered intoxicated.

Matthew Walker: [00:04:40] After 20 hours of no sleep, after 20 hours of being awake for straight, you are as cognitively impaired as you would be if you were illegally drunk.

Jordan Harbinger: [00:04:47] Right. So if you work late and you got up at six and now you're going home at 10, like every lawyer on Wall Street, you better work in Manhattan and take the train home because otherwise you're too tired to drive.

Matthew Walker: [00:04:59] And if you look at the profile of accidents, and you sort of make it relative to the amount of traffic on the road, you see exactly that type of nighttime spike, and it's quite frightening. I should also know by the way that road traffic accidents are a lot more deathly when they're caused by insufficient sleep than either drugs or alcohol. Firstly, we know that a lack of sleep and fatigue causes more accidents on our roads than drugs and alcohol combined.

Jordan Harbinger: [00:05:24] Wow.

Matthew Walker: [00:05:25] But the reason that they're more fatal is because with drugs or alcohol, which are obviously desperately bad when it comes to driving. There, you tend to make a late reaction, so your response is too late or your responses inappropriate. When you have what we call a microsleep, which is where you're driving and you sort of your eyes just close over for a couple of seconds and then you come back around, you get this kind of like head nod microsleep. There, you don't make any response or any whatsoever. That's the difference between being under the influence. First is having a microsleep, at least you make some kind of a correction, some kind of effort breaking, you're late at breaking, but at least you're breaking. When you fall asleep, there's no breaking at all on, and it that moment there's a two ton missile traveling at 65 miles an hour, and no one's in charge.

Jordan Harbinger: [00:06:18] Right. And yeah, that's terrifying. And I think we've all been maybe I'm outing myself there. I think everyone at one point in their life at least once has probably dozed off behind the wheel and they're like, "Wow, that was really scary." "Oh my gosh, I need to pull over." Somebody — I mean, I've done that in college or been in a car with my college roommate and I'm like, "Hey, we're on the rumble strips." "Oh my God, he's asleep." "Oh yeah, sorry, I'm just really tired." "Hey, you okay to drive?" "Yeah, I'm fine now." And then I'm like, "Okay." Which is completely inappropriate response and the response should be "No, pull into that McDonald's for the next 90 minutes." We're all sleep–

Matthew Walker: [00:06:52] Take a nap.

Jordan Harbinger: [00:06:52] You take a nap, wake up, get coffee.

Matthew Walker: [00:06:55] Yep, exactly.

Jordan Harbinger: [00:06:55] Let it kick in the half hour of what is it called? Like when you wake up?

Matthew Walker: [00:06:59] Sleep inertia.

Jordan Harbinger: [00:07:00] Sleep inertia. Wait for that to wear off then get back on the road or switch drivers entirely.

Matthew Walker: [00:07:05] Exactly, yes. But shift, gets some sleep, and once you get that first hit of a asleep attack, when you're driving, trust me, it's only going to get worse. It's a dose-response function. So the further and further you keep trying to battle it, the more and more frequent those will happen. If people — and people have told me this, "I'll drive up to a stoplight and I'm so glad that it's red because I know that I'm just going to get the chance for just a wee little sleep." Oh my goodness. At that point, don't risk it. It's a terrible thing to have the weight and the guilt of someone else's life lost on your shoulders, let alone your own or other people in the car. It's just not worth it. It honestly isn't.

[00:07:46] And it's not about staying up all night, by the way. We know that if you're driving a car and you've only had six hours of sleep, you're 33 percent more likely to get into road traffic accident. So no one would come up and say, "Hey, we've got a great new car. It's fantastic. The only downside is that it's 33 percent more likely to get into a crash." No one would buy that car. That's exactly however, what happens when you get into a car and you've only slept six hours.

Jordan Harbinger: [00:08:14] Which is like every buddy that I know pretty much.

Matthew Walker: [00:08:17] Yeah, based on the numbers. We know that almost one out of every two American adults, in fact, one out of every two adults in most developed nations is trying to survive on six hours of sleep or less during the week.

Jordan Harbinger: [00:08:28] So we're all driving around pretty much worse than drunk.

Matthew Walker: [00:08:32] I think there is a safe bet to say that fatigue is a major catastrophic problem on our roads today.

Jordan Harbinger: [00:08:39] So let's say, all right, fine, I take Uber to work or I ride my bike, which you can't be any safer, or maybe I ride the train or the bus, so I don't have to worry about sleep. That's just my existence, but that's not really true. What else happens when we don't get enough sleep?

Matthew Walker: [00:08:53] Every major physiological system in your body and every operation of the mind is incredibly dependent on sleep, wonderfully enhanced when you get it, and markedly impaired when you don't get enough.

Jordan Harbinger: [00:09:05] Everything?

Matthew Walker: [00:09:05] Everything, yeah.

Jordan Harbinger: [00:09:06] Oh, that's it? Fine, no problem.

Matthew Walker: [00:09:08] Where do we go from here? Well that's the end of the [indiscernible][00:09:11]

Jordan Harbinger: [00:09:11] Your life is terrible if we don't sleep enough. You'll die young.

Matthew Walker: [00:09:14] I mean, well and that is actually the truth though. The last statement that you made, we know that short sleep predicts all-cause mortality. It's a simple fact. The shorter your sleep, the shorter your life. And there's a recent study that came out about 12 weeks ago now from Sweden. They looked at about 50,000 people and probably one of the most striking findings was that if you're trying to survive or regularly getting five hours of sleep or less, you have a 65 percent risk of dying at any moment in time, increased risk relative to people who are getting 8 hours or more.

Jordan Harbinger: [00:09:46] Just for any reason at all?

Matthew Walker: [00:09:48] Yeah, for all cause [indiscernible] [00:09:48].

Jordan Harbinger: [00:09:48] Like heart attack, stroke obviously.

Matthew Walker: [00:09:50] Correct.

Jordan Harbinger: [00:09:5] And usually just dropped dead for no reason, yeah.

Matthew Walker: [00:09:52] That's right. And we can go — we can sort of then say, okay, if that's the bigger picture, what is so deathly about sleep? Every disease that is killing us in the developed world now has a causal link to insufficient sleep. That collection, that list currently includes cancer and Alzheimer's disease. The two most feared diseases. It doesn't stop there though. It's also stroke, cardiovascular disease, diabetes, obesity, depression, anxiety, and most recently suicidality as well.

Jordan Harbinger: [00:10:21] Geez. All from, "Oh, I'll just watch another episode of whatever's on Netflix," or "Oh, I have to get up early and I'm not going to bed on time."   I mean, it seems like such a crazy price to pay because we're kind of conditioned I think, and correct me if that's even possible, but a lot of people, or my friend Jacko for example, Navy seal gets up at 4:30 a.m every day. I'm like, "Oh man, do you go to bed at 9?" He's like, "No, I go to bed at 11. I just don't need as much sleep." And I thought, "Oh, did that just come up? Well, are you always like that?" And he's like, "No, I got it when I was in the military," and I thought, "Oh, okay, they train this into you." But are they training it into your body or are you just training yourself to deprive yourself of what you need on a regular basis?

Matthew Walker: [00:11:05] So based on the wealth of the evidence, and this is evidence from probably over about a hundred thousand studies now across different domains, the number of people who can survive on five hours of sleep or less, and without showing any impairment rounded to a whole number and expressed as a percent of the population is zero.

Jordan Harbinger: [00:11:25] Really? So basically there's some freaks of nature that can get by on very little sleep.

Matthew Walker: [00:11:31] There's a tiny fraction. There is a genetic abnormality, and we know the gene, it's called Dec, D-E-C, which allows people to sleep around about five and a half, six hours of sleep and they don't seem to show any impairment. Now, at this point, there's probably a lot of people thinking, "Oh, I wonder–

Jordan Harbinger: [00:11:52] I have that.

Matthew Walker: [00:11:53] Yeah, "I wonder if I'm one of those people," just to give you a sense, it's a tiny fraction of 1 percent of the population. It turns out that you are far more likely to be struck by lightning in your lifetime. The odds of which are about one in 12,500 than you are to have this gene.

Jordan Harbinger: [00:12:09] That's  far better than I thought in terms of getting struck by lightning.

Matthew Walker: [00:12:11] Yeah. It's actually a hard, isn't it? I'm shock by that statistics.

Jordan Harbinger: [00:12:13] I thought you said one in a million. Quite a good chance actually.

Matthew Walker: [00:12:17] Yeah. But your chances of having this gene or infinitesimal, so I think there may be people who either have that gene and are capable of it, but those people who usually think that they can survive on insufficient sleep, it may not get you acutely. One way that it can pop you out of the gene pool very quickly is just as we were sort of discussing which is a road traffic accident that you can die and there are vast amounts of people. For every 30 seconds that we've been talking that has been a road traffic accident in America caused by insufficient sleep.

Jordan Harbinger: [00:12:54] Geez.

Matthew Walker: [00:12:54] So that's one way that it will pop you out of the gene pool very quickly that way. The other way, however, is chronically and acutely. And so you can have people in their 40s or in their 50s to say, "I've been sleeping for five hours at night for most of my life and I'm still here and I'm still fine." But it's a little bit like high blood pressure. You don't know you have it until finally you have that heart attack at 57, and you either survive or you don't. And so I'm always weary of that mantra to say, "Look, I'm in my 50s. I've had a very successful career. I'm free for the most part of any major disease. And I've been sleeping five to six hours at night and then several years later that person gets a diagnosis of bowel cancer or prostate cancer or one of the other cancers that we know. In fact, I should know by the way that the link between a lack of sleep and cancer is now so strong that recently the World Health Organization decided to classify any form of nighttime shift work as a probable carcinogen.

Jordan Harbinger: [00:13:53] So working overnight will give you cancer period. Pretty much.

Matthew Walker: [00:13:57] The rate of the increased probability, is so dramatic that they listed that category of jobs as in the bucket of being a probable cause that [caused tension] [00:14:07]

Jordan Harbinger: [00:14:07] Are there any other animals besides humans that will purposely deny themselves the right amount of sleep?

Matthew Walker: [00:14:13] Human beings are the only species that will deliberately deprive themselves of sleep for no apparent gain. There are probably, three circumstances under which animals will seem to undergo sleep deprivation. The first is migrating birds. There's actually a fascinating story about this. There is a bird called the White-Crowned Sparrow and it turns out that the American military, particularly DARPA, the at the advanced Defense Advanced Research Projects Agency, invested millions of dollars into this tiny little passerine bird. The reason is this. During its migratory phase, it goes for long periods or a long stretches where it doesn't seem to be sleeping because it's flying a lot. And what they noticed was that when you deprive that bird of sleep during that period, it doesn't seem to show many physical or cognitive impairments, but when you deprive that same bird of that same amount of sleep but outside of its migratory window, it just falls apart. In other words, for a short period of time, there is something biochemically or biological at least, that it is capable of deploying that prevents it's suffering that develops immunity, resilience against sleep deprivation. And so the military obviously thought "Goodness, if we could discover what this is, we could create the 24 hours soldier. We could augment the biology of our military and make them needs sleep less or not at all healthy."

Jordan Harbinger: [00:15:46] That's so healthy. What could go wrong?

Matthew Walker: [00:15:47] So that's one circumstance. The other circumstance is that we've seen in killer whales when they give birth to the young, the mother will often undergo sleep deprivation caring for its young. It seems to deliberately stay awake for longer periods of time. Then once that young has sort of being reintegrated to the pod because they tend to go out away from the safety of the pod from its clan to give birth and then they come back and once they come back they start sleeping normally again, but for that period that's sleep deprived. The final circumstance, which is really interesting is if you put an animal under conditions of starvation, it will start to increase the amount of time that it's awake. The reason being is because starvation is a signal to suggest that it needs to forage a wider perimeter than it otherwise normally would, and to do that, it has to be awake for longer.

Jason DeFillippo: [00:16:44] Hey, don't fall asleep just yet! You're listening to the Jordan Harbinger Show with our guest Matthew Walker. We'll be right back.

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Jordan Harbinger: [00:20:14] I always had a secret suspicion. You know how people in LA are always like, "Oh, I'm doing a fast and I have so much energy." I'm always like, "Yeah, because your body's like, Oh crap, I need food so bad. I need this extra energy."

Matthew Walker: [00:20:25] Exactly.

Jordan Harbinger: [00:20:25] Is that's true?

Matthew Walker: [00:20:25] No, I think you're absolutely right. Well it hasn't actually been demonstrated in the literature. The only evidence that I know of is research studying people during Ramadan where there's a long period of fasting and what they have found is just what you described, which is that sleep typically get shorter and more fragmented under conditions of starvation. Now I think there is an interesting movement right now where there is prolonged fasting or intermittent fasting. I actually have done a lot of research and reading on that evidence. I actually think it's quite a good practice. It causes what we call a tougher G, which is where the body essentially cannibalizes cells that have lived their life and need to be removed out of the system and time restricted feeding or even fasting seems to be able to remove that, and it is good for longevity on the basis of many of the reports.

[00:21:19] So I am suggesting that I think intermittent fasting is a good thing. What you should know however, is that when you undergo that intermittent fasting, your sleep will more than likely get worse or at least will become shorter in duration. That may mean that when you sleep, the quality is ironically better because you have such a short period of time to get the sleep that when you do, the brain latches onto it and basically creates a supercharged version of sleep, you get actually typically a lot more deep sleep. I don't think, however, that is sustainable. So people should not take that suggestion as meaning that you can start to just live chronically on short sleep. You cannot. The evidence is overwhelming. You will live a shorter life and the quality of that now shorter life will be significantly worse. But when you wanted to go fasting, you should probably expect to see a significant change in your sleep for exactly the reason that we've just discussed.

Jordan Harbinger: [00:22:17] An intermittent fasting for people that don't know is essentially, and there's different versions of this of course, but the usual fitness version is getting all your food during the day, during an eight hour window. So not eating dinner too late, not maybe skipping breakfast entirely that way you have sort of a 16 hour period where you're not eating anything.

Matthew Walker: [00:22:35] Yes. So that would be classified as time restricted feeding. And there's a wonderful scientist such in Pendra at the sulk who's done a lot of great work on this too, and then there is intermittent fasting, which is where you will perhaps go forth 24 or even 48 hours without food.

Jordan Harbinger: [00:22:50] I see.

Matthew Walker: [00:22:52] That usually means even without coffee, if you're going to do it, just black coffee, no sugar, no sweetener, no cream, no milk. That can happen for 24 hours, sometimes 48 hours as well. People tried to sometimes push it further so that they go into a state called ketogenesis, which is where they start burning your natural fat stores and there's a benefit there too but, yep.

Jordan Harbinger: [00:23:13] Sure, yeah. Beyond the scope of the book definitely. I don't usually cover fitness and so I'm always like, okay, but it's different because you are actually a PhD. The problem is when guys come on and they're like, "Look, I'm 21, I've read everything about this. Let me come on and tell people how they cannot eat for 30 days and why it's good for you." And I'm like, "Pass." But not the doctors know everything.

Matthew Walker: [00:23:35] No, doctors need to achieve nice thing. They know little, they know something, but they know a little. I am just as much of a student of sleep as most other people.

Jordan Harbinger: [00:23:46] That's great, yeah. I appreciate that. In the book, Why We Sleep, I thought there's a lot of interesting stuff in here. I've got way more notes than we could possibly record, but I thought it was interesting that even plants have a circadian rhythm. What was the experiment? I don't know if it was you who ran it, but it was like plants in the dark. They're not going to open their leaves and sure enough, they still kept the rhythm, even though they would probably pretty damn confused about why there was no sun.

Matthew Walker: [00:24:08] Yeah. Every living species that lives at least longer than 24 hours seems to have some kind of rhythmic activity to it. And that rhythmic activity is hardwired into not just our brains, but every cell of our body. All of our cells have little clocks inside of them, 24 hour clocks. Now, there is one master clock that sits within the brain of human beings and that's called the super charismatic nucleus. So it's a little bit like Lord of the Rings, it's one ring to rule them all. Well, there is one clock to rule them all and that sits within the brain.

Jordan Harbinger: [00:24:40] Got it.

Matthew Walker: [00:24:42] But you have clocks all over the body and they understand the 24 hour rhythm because we evolved on a planet that rotates around the sun, and so from the start of time the sun has always risen and the sun has always set, and that rhythmic activity changes, light changes, temperature changes, pressure that changes our biology, and species have to be aligned to those fluctuations. What helps us align to that is our internal body clock. That's where we get our timing from and it's not just human beings, as I said, even bacteria that live a couple of days seem to have some kind of rhythmic active state in a passive state, it was probably the precursor of what we now call weakened sleep. So what that tells me is that sleep evolved with life itself on this planet and from that point forward it is fought its way through heroically, every step along the evolutionary path.

Jordan Harbinger: [00:25:39] Now some people go to bed late, they get up early. This makes sense for — this is another one of my theories based on absolutely nothing other than reading a lot, but I assume that this happened because we're tribal and it's good for some people to be awake pretty much all the time, not the same people though, right?

Matthew Walker: [00:25:55] Exactly.

Jordan Harbinger: [00:25:56] So hey, this person gets up early, great. I can sleep in a little, I'll stay up late while these older folks go to bed early, our chances of getting eaten by lions diminished by that much, right?

Matthew Walker: [00:26:06] Yeah, and that's the theory that I said tried to put forward in the book. So we all have something called a chronotype, which is your natural timing tendency for when you want to be awake and when you want to be asleep. Some people are sort of night owls, other people are morning larks.

Jordan Harbinger: [00:26:24] Yeah, Daniel Pink wrote about this in a book recently called When. We covered it on the show.

Matthew Walker: [00:26:28] Okay.

Jordan Harbinger: [00:26:28] Where some people get up 5 a.m, they're totally fine or 6 a.m, other people, it's like how do people get awake before 10 a.m?

Matthew Walker: [00:26:36] Yep, precisely that, and we know it's called your morningness or eveningness score. It is not a choice. People need to firstly realize that, if you are an evening type and you're being shamed because you're not at work at 7 o'clock in the morning or you can't function at 7 o'clock, that's not your fault. It is genetically hardwired. We know the genes that dictate whether you're a nighttime person or a morning person. Why is that? Sort of, just to take a step back to your question though, which I think is a beautiful one. Why would we have designed such variability? It turns out that if you look at hunter gatherer tribes who are untouched by electrical civilization, they typically sleep as a group, as a collective, as a tribe, just as you described. And this then comes onto why it would be beneficial because from an evolutionary standpoint, think about sleep. It is the most idiotic of all things because when you're asleep, you're not finding a mate, you're not finding food, you're not reproducing, you're not caring for your young and worse, still your vulnerable to predation.

Jordan Harbinger: [00:27:39] Sure, yeah. It seems like a waste of time, if we put it that way.

Matthew Walker: [00:27:42] On any one of those grounds. But all of them combined, sleep should've been strongly selected against in the course of evolution. The fact that is persisted and is preserved in every species that we've studied to date means that if sleep doesn't serve an absolutely vital function, it's the biggest mistake the evolutionary process ever met. So what's then peculiar, however, is how could you risk mitigate what seems to be a biological necessity? Well, here's a great idea. If you are a co-sleeping species and you've got a 24 hour period and you all slept at the same time because your genes all want you to sleep from midnight to 8 a.m in the morning, you're all going to be vulnerable for eight hours. However, why don't we shuffle the debt genetically? Why don't we have some people who are going to bed at 9 a.m, and waking up at 4 or 5, other people that are going to bed at, 11 p.m waking up at 7, other people are going to bed at 3 a.m waking up sort of at 11 or 12. Now all of a sudden everyone still gets their chance to get eight hours, but you as a collective species are only vulnerable for maybe two hours and so it's a beautiful mechanism by way of nature, and this is just the theory. This is just the theory I put forward in the book. I don't know if there's any good evidence right now for it, but I think it's a tenable possibility.

Jordan Harbinger: [00:29:05] Tell us about sleep pressure because this kind of larks back or harks back to the idea that we're falling asleep in the car and things like that. I thought you just started to fall asleep when you're tired, but actually there's hormones that build up. Are they hormones they build up in your body, chemicals that build up in your body that eventually you just can't resist, and caffeine and things like that sort of turn those switches off temporarily? And then when the caffeine goes away, it's like, "All right, I'm leaving flips the switch back on," kind of just walks out of the room, and you're like, "I'm freaking dying now." That's the crash, right?

Matthew Walker: [00:29:35] That's the crush, yeah.

Jordan Harbinger: [00:29:36] I didn't know there was such a thing as sleep pressure.

Matthew Walker: [00:29:38] There is. So sleep pressure is caused by a chemical and that chemical has a name, and it's called adenosine. Now, from the moment that both you and I woke up this morning, that chemical has started to build up in our brain and the more of that chemical that builds up the sleepy of that you will feel, and after about 16 hours of accumulation of adenosine, you should feel sleepy enough so that you will fall asleep easily and then stay asleep throughout the night. When we sleep, the brain, particularly during the deep stages of sleep, will actually clear out that adenosine, that sleep pressure.

[00:30:17] So when we sleep, think of it like a pressure valve on a pressure cooker that all of a sudden, you just release that 16 hours of sleepiness and you can do it within eight hours, so that when you wake up the next morning, you feel refreshed, you're alert, and you can go for a neck and other 16 hours. That's where caffeine comes in though because they sound quite similar. Adenosine and caffeine, the end of them is the same and it's for good reason pharmacologically. Caffeine will actually race into your brain and it will latch onto the welcome sites for adenosine what are called receptors and adenosine is pushed out of the way. Caffeine jumps and hijacks those receptors, but when it locks onto those receptors, it doesn't stimulate them to create more sleepiness, it just blocks them to prevent the sleepiness signal. So it essentially is like the mute button on your remote for the TV. You've got lots of volume. It's increasing across the day. It gets to some loud sort of pressure and you fall asleep, and then caffeine comes along and it races in and it just mutes the signal or it drops the signal down by let's say 50 percent. So your brain was thinking, "I've been awake for 13 hours, 14 hours, 15 hours," then you swig some caffeine and your brain thinks, "Oh, hang on a second. It looks like I've only been awake for seven hours now," because he's not getting all of that sleepiness precious signal.

[00:31:44] The problem is that for the duration during which that caffeine is in your system, it doesn't stop the brain producing adenosine, the sleepiness chemical, that continues to build. So then by the time the caffeine is washed out of the system, not only do you go back to having the whole weight of sleep pressure that you had four hours ago or three hours ago, you have that plus all of the additional weight that's been building up while the caffeine is in your system and that is called a caffeine crash. So now you actually have to start reaching for more caffeine to get back to where you were and it's a vicious cycle. So that's one of the problems with caffeine in terms of sort of its alertness and its caffeine crash. Caffeine, however, has a marked impact on your sleep. Most people know that it's a stimulant. It's what we call psychoactive stimulant.

Jordan Harbinger: [00:32:37] It has to be, because otherwise it wouldn't work. If I woke up fully refresh and I drank caffeine right when I get up and I had no adenosine really building up, then I wouldn't need any caffeine and it would have in theory no effect.

Matthew Walker: [00:32:51] That's right.

Jordan Harbinger: [00:32:52] So it has to have some sort of additional effect other than just blocking those receptors. Otherwise I could drink a whole pot of coffee and feel exactly the same as if I didn't, as long as I drank it right when I woke up.

Matthew Walker: [00:33:01] Definitely has some properties where it's thermogenic too. So it will increase your core body temperature, which will typically increase your alertness. That's why a hot drink, even in the mornings, even if it's non-caffeinated will typically help you because your body needs to rise in its core temperature to wake up naturally.

Jordan Harbinger: [00:33:19] I didn't know that.

Matthew Walker: [00:33:20] It's a good hack for people actually is to sort of fit your thermostat for maybe half an hour before you want to wake up and you can use that thermal cue. But caffeine is a problem, firstly, if you're drinking caffeine before midday, then you're probably self-medicating your state of sleep deprivation.

Jordan Harbinger: [00:33:42] Right, right.

Matthew Walker: [00:33:42] And I look around on playing some times when I'm departing at 10 o'clock in the morning. That should be starting to get to your peak level of alertness, depending on what your chronotype is. But it used to be that you couldn't use your phone, you couldn't do anything on takeoff for that 40 minute period. And boredom is a wonderful way to unmask your chronic state of sleep loss. And I would look around and half the plane was asleep at a time when biologically it should be almost impossible to sleep. But coming back to caffeine, it has a couple of stings in its tail. Firstly, for some people, caffeine will just keep you wired so you can't fall asleep or you wake up throughout the night. But there are people who will say to me, I can have a cup of coffee with dinner and I can fall asleep and I stay asleep just fine.

Jordan Harbinger: [00:34:26] Like any Italian person who has a shot of espresso before dinner and a shot of espresso after dinner, shot of espresso before bed. And I'm like, "How many of you have each day?" "I don't know, 16, 17."

Matthew Walker: [00:34:36] And I sleep like baby.

Jordan Harbinger: [00:34:37] And they're out, man. Passed out on the couch.

Matthew Walker: [00:34:39] It's possible that they will maintain their sleep. But we've done studies where if you give people just a standard dose of a cup of coffee, which is 200 milligrams of caffeine, just in the evening, and then you measure their sleep relative to when they have not had caffeine in the evening, what you typically see is about a 20 percent loss of deep sleep. Now to put that in context, I would have to age a human being by about 20 to 30 years to produce a 20 percent reduction in deep sleep, or you can do it by just having a cup of coffee in the evening.

Jordan Harbinger: [00:35:15] Geez, the caffeine half-life just keeps everything going on in your system.

Matthew Walker: [00:35:20] It does.

Jordan Harbinger: [00:35:21] Which delays the deep sleep onset.

Matthew Walker: [00:35:23] And it prevents deep sleep. It has a mechanism that we understand. And your point by the way, about half life is a really important one too. We know that caffeine has a half-life of about six or seven hours, but caffeine has a quarter life of 12 hours. What that means is that if you have a cup of coffee at noon, a quarter of that caffeine is still circulating around your brain at midnight and it would be the equivalent of tucking yourself into bed at midnight. And just before you turn the light out, you swig a quarter of a cup of Starbucks and you hope for a good night's of sleep.

Jordan Harbinger: [00:35:53] Yeah, not going to happen.

Matthew Walker: [00:35:54] It's not going to happen, but that's what you do to yourself. If you have caffeine afternoon.

Jordan Harbinger: [00:35:59] Yeah. I think people get confused about half-life because they go, "Oh well, that means that, so if it's a six hour half-life, then half of its gone by 6, and it's all gone by midnight." It's like, "No, no, no. You have the half. You don't just get rid of the second half, yeah. It's kind of hard to wrap your brain around things like half-life until you look at maybe a graph because it's a curve. It's not like —

Matthew Walker: [00:36:20] It's an exponential decay, which yeah, still kind curve but it's a much better word than.

Jordan Harbinger: [00:36:24] What is it asymptote?

Matthew Walker: [00:36:26] Yeah.

Jordan Harbinger: [00:36:26] Is that what it's called?

Matthew Walker: [00:36:27] Yeah, asymptote where it flattens out, yeah.

Jordan Harbinger: [00:36:28] Right.

Jason DeFillippo: [00:36:30] You're listening to the Jordan Harbinger Show with our guests, Matthew Walker. We'll be right back after this.

Jordan Harbinger: [00:36:36] This episode is also sponsored by Outerknown. Finding great quality clothes that fit great isn't always easy and Outerknown clothes are for, for people in planets, high quality, sustainable clothes, durable construction, and a great fit. But what I will be, I got to just tell you that. Look, that's the tagline that I got to read here. Kelly Slater has designed this stuff. He's an 11 time world surf league champion and all copy bolognaise side here. This blanket shirt I got from Outerknown, I put it on when I got it and I thought I should wash this later, whatever. I wore it for five straight days.

Jason DeFillippo: [00:37:11] I'm sure Jen was happy about that.

Jordan Harbinger: [00:37:13]  Jen was like, "This is really cool. Oh, it's really nice." She liked it, but yeah, maybe on day five she's like, "How about we try another kind of shirt today, huh?"

Jason DeFillippo: [00:37:20] Get a little funky maybe.

Jordan Harbinger: [00:37:22] Well, I'll tell you, it's like a flannel shirt, but it feels like you're wearing an actual blanket. It's just that it looks like a regular flannel shirt, so it's perfect holiday, whether it's kind of PJ-ish, but you can also go out to holiday shopping or out to dinner in it. It's really awesome. I love this thing. I'm going to get another one, and the mission of Outerknown is to provide great clothes that don't harm the environment. They only work with factories that pay fair living wage, have safe working conditions, et cetera. So I got to tell you this blanket shirt, if you just even — humor me on this, go to outerknown.com and look for the blanket shirt, and Jason, we've got a deal for them as well.

Jason DeFillippo: [00:37:57] Go to outerknown.com today and enter code JORDAN at checkout and you'll get 25 percent off your full price order. That's outerknown.com. O-U-T-E-R-K-N-O-W-N.com and remember to use the code JORDAN at checkout for 25 percent off. Check them out today outerknown.com, promo code JORDAN for 25 percent off.

[00:38:16] Thanks for listening and supporting the show. Your support of our advertisers is what keeps us on the air. To learn more and get links to all the great discounts you just heard, visit jordanharbinger.com/deals, and don't forget the worksheet for today's episode. That link is in the show notes at jordanharbinger.com/podcast, and now please try to stay awake for the conclusion of our interview with Matthew Walker.

Jordan Harbinger: [00:38:41] So how do we know if we're getting enough sleep generally? Because it's clear that we're all just not and we're going to die young of terrible diseases, but how do we know, look, I'm self-employed, I can get enough sleep if I want to, which is kind of half the reason I'm self-employed because I remember as a kid getting up for school and being just chronically under slept and just thinking they're going to find out in 20 years that this is so bad for us, and now and they did by the way, right?

Matthew Walker: [00:39:08] Once a week, yeah. And what are we doing? In fact, there is right now as we speak, there is a law going to the California legislature to actually try to delay school start times here, and I've lobbied that, I actually sent them a letter, posted to out on Twitter, imploring them to make this vote. And the evidence is very clear that when we delay school start times, academic grades increase, behavioral problems decrease, truancy rates decrease, psychological and psychiatric issues decrease. But what we also found, which we didn't expect in those studies is the life expectancy of students increased. And you may be thinking how is that possible?

Jordan Harbinger: [00:39:48] Yeah.

Matthew Walker: [00:39:49] The leading cause of death of adolescent teens right now is actually not suicide that second. It's road traffic accidents.

Jordan Harbinger: [00:39:56] Oh, sure. Drunk driving.

Matthew Walker: [00:39:58] And it comes back to this and there was one study for example in 10 County in Wyoming, they delayed the school start times from 7:30 in the morning to 8:55 in the morning. The only thing more impressive than the one hour of extra sleep at those teens reported getting was a 70 percent drop in road traffic accidents in vehicle car crashes in that narrow age range of 16 to 18. So if our goal as educators truly is to educate and not risk lives in the process, then we are failing our children in the most spectacular manner with this incessant model of early school start times.

Jordan Harbinger: [00:40:32] Yeah. When I was a junior, I had a study hall that I could move around. So I moved that naturally to the first period. I took an elective that was a self-study thing during the second period so that I just did it after school and then I had a weightlifting class where you could make up any weightlifting session at any other free point during the day because they thought we would study otherwise or we would work on projects and things like that. I don't remember exactly how it worked. So basically the first three periods where I could just sleep in.

Matthew Walker: [00:41:03] Genius, you hacked to the system to sleep.

Jordan Harbinger: [00:41:05] And my grades went through the roof. My mom would go, "Hey, shouldn't you be in school?" And I'm like, "Look, I made it so that I don't have to be there until 9:30 or whatever it was. So I would get up at like 8 or 8:30 instead of 6 a.m after doing my homework until 12:30 because I  had for five hours of homework.

Matthew Walker: [00:41:21] Exactly.

Jordan Harbinger: [00:41:22] My grades went through the roof during the hardest year of high school. And I was in a good mood and everything changed. Everything changed.

Matthew Walker: [00:41:29] It is radical that changed too. And for a 7:30 start time should note that some school buses will begin leaving at 5:30 in the morning.

Jordan Harbinger: [00:41:36] That's obscene.

Matthew Walker: [00:41:37] That means that some kids are having to wake up at 5:15, 5 o'clock maybe even earlier. This is lunacy. And by the way, 7:30 a.m for a teenager is the equivalent for an adult of them waking up at 4:30 or 3:30 in the morning.

Jordan Harbinger: [00:41:56] Wow!

Matthew Walker: [00:41:56] It's not the same when you are that age because during adolescence your biological, your sort of essential chronotype starts to shift forward in time. You want to go to bed later, you want to wake up later, you become more like an owl rather than a lark. But yet education is born within the mold of grown adults. Teachers —

Jordan Harbinger: [00:42:16] Sure. And they want to get home early so they have the rest of the day to get things done.

Matthew Walker: [00:42:20] Administrators, exactly right. And they're waking up 7 o'clock or 6:30, and maybe that's not too bad for them. But that's like asking an adult to wake up as I said, 4:30 and wake up and learn efficiently and act with grace and not suffer mental health problems. It's just not going to happen.

Jordan Harbinger: [00:42:37] I've told my wife Jen this over and over, I said, we're going to figure out a way that our kids are going to get enough sleep. I'm not going to turn into one of those adults who's like, "Well, I had to do it so you have to do it," because it's not laziness.

Matthew Walker: [00:42:49] It's not, no.

Jordan Harbinger: [00:42:50] I worked my butt off in school. I was not lazy, but I needed that sleep. I know that it was biologically necessary, but of course my dad's like, "Get up! It's 8:30." I'm like, "It's Saturday first of all." And two, "I didn't go to bed at 8:30 p.m, Dad. I went to bed at 1:30 a.m,.

Matthew Walker: [00:43:05] Well, and furthermore, what you're simply doing is trying to sleep off a debt that the school system is desperately lumbard you with during the week. And we know that about 70 percent of parents, of teenagers believe that the teen is getting enough sleep, yet only 11 percent of teens are actually getting the sleep that they need. So there is a mismatch and I think what's happening is that there is a parent to child transmission of sleep neglect that they rip the covers off of the weekend. They say you're wasting the day, you know what's going on? And then what happens in 20 or 30 years' time, those teens become parents who then pull the sheets off their teenagers and say the same thing. We need to break that viral transmission.

Jordan Harbinger: [00:43:49] I agree. Look, if administrators out there listening, if you can do anything about this, change it. I know you want to get your errands done. Why don't you read, pick up a book, listen to a podcast early in the morning, quit bugging your kids. Can we make up for sleep? You brought up this, the sleep debt idea. Can I just deprive myself for five straight days and I'd sleep all weekend or am I actually not really solving the problem here?

Matthew Walker: [00:44:11] You're not really solving the problems, so sleep is not like the bank that you can't accumulate a debt and then hope to pay it off at a later point in time. Now there was I should note a recent study that was published which suggested that those people who are short sleepers during the week and then a longer sleepers during the weekend actually have a reduced level of mortality, of risk of death relative to those people who are short sleeping during the week and then short sleeping during the weekend as well. So there's some degree of trying to sleep it off that seems to benefit. However, if you look at the details of that paper, you should be weary. It was all over the press as if this was some green light to do that. By the way, that's called social jet lag and it's very bad for your health where you actually short sleep during the week and then you binge at the weekend, you sleep late, and then come Sunday night you have to try and drag your body clock back sort of two or three hours. It's the equivalent of flying back and forth from San Francisco to New York every weekend. It's torture on your biology. But if you looked at that paper more closely, what you found is that those people who are short sleeping during the week and long sleeping during the weekend where about twice as likely to be in very poor health, they were about 30 percent more likely to smoke. They were twice as likely to be abusing sleeping pills. And so I just don't think the recommendation is there right now. You could argue by the way, why isn't there a banking system like that in place?

Jordan Harbinger: [00:45:45]Yeah.

Matthew Walker: [00:45:45] Wouldn't that be useful? Because there is precedent in biology for a system like that and it's called the fat cell. Because there were times during our evolutionary past where we had caloric famine and we had caloric feast where we had lots of food and then we had no food at all. And the body came up with a brilliant solution, which is a storage cell, a credit system for calories where you could store up when you had a feast in the form of fat. And then you could spend that caloric credit when you went into debt during famine. Where is the fat cell for sleep.

Jordan Harbinger: [00:46:21] Right, yeah.

Matthew Walker: [00:46:22] Wouldn't that be one? And there is no fat cell. The reason is because as we discussed, human beings are the only species that deliberately deprive themselves of sleep. In other words, mother nature has never been forced to face the challenge of a chronic sleep debt. Mother nature has therefore never had to come up biologically with a solution to overcome insufficient sleep. That's why we implode so demonstrably, so quickly when we go without sleep.

Jordan Harbinger: [00:46:50] Why do I always wake up right before my alarm? What's going on there? I don't even need alarms. I can say I've got a flight at this time. I always — almost always can just decide about what I'm going to wake up and pretty much nail it. I've always been like that. What's going on there?

Matthew Walker: [00:47:05] So if you're getting sufficient sleep, your body will just typically acclimate to its natural amount. And by the way, this comes back to your question which I failed to answer to before, which is how do you know that you're getting enough sleep?

Jordan Harbinger: [00:47:17] Right, yeah.

Matthew Walker: [00:47:17] One of the ways is that you have — you can wake up naturally. So a good demonstration of you not getting sufficient sleep would be this. Would you oversleep or would you sleep in if you didn't have an alarm? And if the answer is yes, then you are under slapped clearly because your body would still need more sleep but you are terminating that sleep artificially. That's probably the very best metric. It's a good metric as a positive, but you can have false negatives. What I mean by that is some people have early morning awakenings due to insomnia and that means that they are — it doesn't mean that they're well rested. It means that there's other problems, usually anxiety typically that are causing early morning awakenings, but for the most part that's one good sign. Would you sleep past your alarm if it didn't go off? If the answer is yes, you're not getting sufficient sleep. Are you using caffeine in the morning to wake up? If the answer is yes, you're probably under slept.

[00:48:14] Other little telltale signs. Have you driven in the morning and you can't quite remember whether the traffic light was red or green that you pass through?

Jordan Harbinger: [00:48:22] I mean, I would hope it was green.

Matthew Walker: [00:48:24] You would hope, but if you're asking that question. Another one is you're just staring at a paragraph that you've read for three times now and you're thinking, why can't I understand what's going on?

Jordan Harbinger: [00:48:33] That was my entire school career.

Matthew Walker: [00:48:35] That experience. Sometimes it's just bad writing, but at the time —

Jordan Harbinger: [00:48:38] I did go to law school. I mean, there's a reason I read the whole thing and went, "Wait, what? What's going on?"

Matthew Walker: [00:48:43] Yeah, yeah. Short of legally, but so those I think are examples of good telltale signs that you're not getting sufficient sleep. But coming back to your point, there are two circumstances where that happens. One is where you're just consistently well-slept and you just typically wake up naturally and your body will find that sweet spot. And we've done these studies where you take people out for two weeks, you say goodbye to your family and friends, put your phone away, you are now basically incarcerated with us and we remove all cues, all clocks, all signs of daylight, and we can just wash you out of all of the ills of modernity and we can see what your natural sleep rhythm is. And firstly, most people acquiesce to about eight to nine hours of sleep in young health.

Jordan Harbinger: [00:49:27] Maybe they're just bored because they don't have their Internet or their TV with them. They think of that?

Matthew Walker: [00:49:30] Well, boredom usually doesn't lead to sleep unless you are chronically under slept.

Jordan Harbinger: [00:49:34] Oh, okay.

Matthew Walker: [00:49:35] If you're bored, you're just going to be frustrated, but the only time boredom leads to sleep is if you are chronically under slept.

Jordan Harbinger: [00:49:42] Okay.

Matthew Walker: [00:49:43] So we can wash people out and then they all just start to find this natural sweet spot where they go to bed at their natural genetic predisposition and they'll wake up naturally and they feel, it's surprising to hear how they feel, which is that they feel fantastic. There's a great study done, not by myself, but a guy called Kenneth Wright professor down in Colorado. He took some people up to the Rockies for camping. These are people who would say, I normally just get sort of seven hours of sleep, that's what I need. Took them up. No light, no electricity, no nothing, no watches, no gadgets, sleeping with biological temperature dictated by the ambient light, dictated by the ambient, and they started sleeping about eight to nine hours again.

Jordan Harbinger: [00:50:27] Wow.

Matthew Walker: [00:50:28] Consistently, this seems to be the natural human tendency. So I think that's one of those things where you will start to wake up naturally. The other, however, is a deleterious case, which is called anticipatory anxiety. Most people will experience it if you have to wake up for an early morning flight or if you've got a job interview that you've got to go.

Jordan Harbinger: [00:50:48] Oh, that's the worst, yeah.

Matthew Walker: [00:50:49] And you just know firstly that your sleep at night is going to be rough. It's not going to be deep. It's going to be shallow quality of sleep. And you can set your alarm for let's say 5:30, and almost guaranteed you'll wake up at 5:28.

Jordan Harbinger: [00:51:03] Yeah, yeah.

Matthew Walker: [00:51:03] As if internally and we are starting to understand these mechanisms, you have some kind of intrinsic quartz like precision metric of time where you don't need an outside clock at least non-consciously you have that clock tick tock of time. One of the problems by the way, in modern society are phones because they create a low level form of this every single day. What most people typically do is they sleep with their phone in their bedroom. Some people are good, but they don't keep it quite by that bedside.

Jordan Harbinger: [00:51:38] Jen, my wife.

Matthew Walker: [00:51:40] But some people do. removing clock faces from your bedroom is one of the best pieces of advice that I can give you by the way. Even if you're good and you keep your phone and you don't look at it during the night.

Jordan Harbinger: [00:51:51] Jen.

Matthew Walker: [00:51:51] A lot of people. I'm so sorry Jen, this is going to be grounds for a marital dispute, I hope not.

Jordan Harbinger: [00:52:00] I tell her this all the time. I'm like, "Don't look." She's like, "I can't sleep. I'm like, definitely looking at Instagram at 3 a.m is a great way to make sure that you don't sleep at all.

Matthew Walker: [00:52:08] Well almost a guarantee that the studies are in for this too. What will happen though is when people wake up in the morning, the first thing they typically do is swipe and unlock.

Jordan Harbinger: [00:52:17] Crap! That's me.

Matthew Walker: [00:52:18] And you just unleashes this wave of anxiety cascades into your day in a way that we have never evolved to really expect this. And just by knowing that, that's how you're going to wake up in the morning when you go to bed at night essentially creates a very micro dose of that same experience that you would have of an early morning flight. So your sleep just isn't a shallow, and we can see this, the amount of anticipatory anxiety correlates with the depth of your sleep. If you have very little, you have lots of luscious deep sleep, which means you wake up feeling refreshed. But if you have a strong level, even a moderate level, you won't sleep as well.

Jordan Harbinger: [00:52:57] So if I'm getting rid of screens in the morning, coffee in the morning, I just realized, my entire life for as long as I've lived has revolved around doing something pretty unhealthy in the morning right when I wake up.

Matthew Walker: [00:53:08] Try, if you can, and I sound like a terrible prude and I've spoken about coffee and we can speak about alcohol too. Life is to be lived to a degree, and I'm not immune to any of these things too, but it's all about — it's not about all and I think it's not about absolutes. It's just about finding that correct sweet spot. Try to just go for five minutes, firstly in the morning without opening your phone.

Jordan Harbinger: [00:53:37] Is it the light from the phone? Like what if, what if I studied Chinese flashcards in the morning instead of checking my email?

Matthew Walker: [00:53:43] So if you were to use your phone to just do a meditation and have it on airplane lock mode so you don't create that anticipation of Twitter, Facebook, Instagram, email, messengers, that's probably not too bad because it's not going to be that what we call fight or flight activating trigger within the nervous system. That's a terrible thing to wake up and expect. So try for five minutes without just plugging into all of those things and then try to extend it. Try to do seven minutes, 10 minutes. So go through to the kitchen, make a cup of —

Jordan Harbinger: [00:54:21] Purple tea.

Matthew Walker: [00:54:22] Purple tea, or caffeinated drink. Finally when you've got some degree of wakefulness, open your phone, open your laptop, do that. But don't wake up expecting that it really can be a ball and chain to a deathly loss if your deep sleep at night.

Jordan Harbinger: [00:54:40] What about jet lag? Are there easier? There's all people like, "Oh, I do this and I don't get jet lag," or "I take this and I don't get jet lag," or "I wear these earphones that have lights in them and I don't get jet lag." Is there any truth to any of this or is it just look, jet lag, we're not evolved for it. It takes time to adjust.

Matthew Walker: [00:54:58] We're not evolved for jet lag and the jet engine was a remarkable invention for the transportation of civilization across around the globe. But that jet caused a terrible lag in our biological time and it's what we call jet lag.  There is no cure for jet lag, but there are some treatments, some hacks that you can actually implement that will help you diminish the severity of jet, it won't overcome it. And the probably, let me see the probably five things you can do to overcome jet lag. Firstly, when you get on the flight, don't sleep in the last, so this is the assumption that you're taking along transatlantic flight, let's say from San Francisco to London, which I will do. I will always try to sleep in the first half of the flight and then I will wake myself up and I will force myself to stay awake for the rest of the flight and throughout the following day when I arrive in the UK. The reason is because I need to build up enough of that sleep pressure so that I fall asleep or give myself the chance to get good nights of sleep.

[00:56:03] So the rule of thumb is make sure that you give yourself at least 14 hours of consistent continued wakefulness from the time that you wake up to the time that you expect or want to go to sleep in the new time zone, which typically means sleep in the first half of the flight. I often see people that mistake, they stay awake for the first half, they sleep in the second half, they arrive, it's a channel ended in 11 o'clock in the morning, and they've only just woken up. Now, if you'd been awake and normally active in London and you've only just woken up at 10:30 in the morning and then you expect to go to bed at 9 p.m in the evening, you're not going to feel very sleepy, but that's what you've done by sleeping late on the plane. That's the first thing.

[00:56:46] The second, avoid alcohol and caffeine on the flight. They are served liberally and freely. Do not do it. Both of them will make it harder for your 24 hour clock, your biological clock to adjust in the new time zone. Once you've arrived in the new time zone, light exercise, and time to feeding all your friends. Firstly, try and get out for at least 30 minutes of natural daylight sometime before 10 o'clock in the morning in the new time zone. Next, try to exercise and try to exercise before midday physical activity. Even if it's just that 20 minute, 30 minute active walk outside. If you go outside in the morning, which you should, it's fine if it's bright and sunny to wear a hat or some block but do not wear shades. I know it looks cool, but keep shades off your face. You want that natural daylight to penetrate. If you go out in the afternoon, it's fine to get daylight in the afternoon, but now is the time to wear shades. Stop blocking that light in the afternoon.

[00:57:52] The next thing is eat meals at a regular time when everyone else is. Don't eat meals when you want to, when you're hungry, which will be mismatched to everyone else's meals. Food is just a powerful trigger and cue to reset your biological clock as daylight is. So do those things, and then expect that your body clock will reset by about one hour for every day that you've been in the new time zone. If I fly back home to England, it's eight hours difference. It's going to take me about eight days before I feel normal. That's the expectation.

Jordan Harbinger: [00:58:26] Interesting. Yeah, that makes sense. So one hour per day. So if we're GMT -7 right now in San Francisco, it's going to take you a full week to fully readjust as long as you do everything else right. If you just keep screwing things up and eating dinner at 3 a.m, and staying up all night, you're screwed no matter what.

Matthew Walker: [00:58:42] Absolutely, yeah.

Jordan Harbinger: [00:58:44] Okay, interesting. There were some–

Matthew Walker: [00:58:46] Oh, by the way, I can say melatonin is another good thing that.

Jordan Harbinger: [00:58:49] I was going to ask about that.

Matthew Walker: [00:58:49 Melatonin is efficacious, yeah. Melatonin is a hormone. That hormone is often called the hormone of darkness or the vampire hormone.

Jordan Harbinger: [00:58:59] Sounds very intimidating.

Matthew Walker: [00:59:00] Yeah, not because it makes you, when you take it look at people's necks longingly and want to bite into them. It's just that that hormone comes out at night. It's the hormone of darkness. Melatonin rises when the sunsets and when we get the signal of darkness, the brain releases its brakes on a gland called the pineal gland, that gland melatonin into your blood stream. Once melatonin circulates around your brain in the body, it tells your brain and body it's nighttime, it's time to go to sleep.

[00:59:29] So melatonin helps time, the healthy onset of your sleep. You can use melatonin strategically in the new time zone. Because when I first arrived in the UK, my melatonin spike is not normally going to happen for seven or eight hours, despite it being 11 p.m at night. When most people in the UK, they're in the full swing of their melatonin rise now. But I can fool my body into thinking that it's nighttime by taking some melatonin. Most people take too much melatonin by the way. They typically take five or 10 milligrams. That's actually too much so that your system will actually start to adapt and become intolerant to the melatonin. Best dose advice is probably about 0.5 milligrams, two milligrams. That seems to be the most efficacious dose.

Jordan Harbinger: [01:00:16] So take that five milligram pill, open it up, dump half of it into your hand, half in the other, choose the smaller half and then down it.

Matthew Walker: [01:00:24]. Exactly, yep. And usually you should take it about 45 minutes before your desired bedtime.

Jordan Harbinger: [01:00:28] Ah, okay. Interesting. Man, there were so many things in the book that were interesting about sleep, obesity, disease, and things like that. I want to sort of wrap though with dreams, but before we get to that, there was something in the book Why We Sleep. That was, you kind of just barely touched on it, but it was — there was a way in which people were using sound to program people's memory during sleep. Tell me what's going on there? Because that just sounds like some black mirror stuff waiting to happen.

Matthew Walker: [01:00:55] Yeah, there should be an episode. So we have done at my sleep center a lot of work on sleep and memory, and we know that sleep after learning will essentially hit the save button on those new memories so that you don't forget. So sleep will actually future proof that information within your brain, but you can even hack that system again too. And there's a clever trick, so there is something called context dependent or cue dependent memory which is where, let's say that you associate a particular set, a list of words with a smell. And then I ask you recall as many words from that list as you can, and maybe you will recall 50 percent of them. But if I say, okay, you recall that list of words, but now I start reperfusing that smell up your nose, you will remember maybe 70 percent of those words because the smell which you originally associated with learning that information when it is re-triggered into the brain, when you are queuing that memory with the smell, you unlock those memories more powerfully. And this is why people, if you study in the room that you're going to take the exam, you will typically do better because you use the cues from around the room as triggers to unlock those memories.

Jordan Harbinger: [01:02:15] Really? Visual because —

Matthew Walker: [01:02:17] Exactly, visual olfactory, sound.

Jordan Harbinger: [01:02:20] Crazy.

Matthew Walker: [01:02:20] All types of sensory. So here's what I can do. I can have you do a memory test where I'm going to teach you a bunch of photographs of different objects, like the photograph of a cat or a fire engine or a cattle. And those photographs will be placed at different low geographical locations on the screen. And then at a later test, I'm going to show you a picture in the middle of the screen and I'm going to ask you two questions. Firstly, did you see this picture before? Yes or no? And if you say yes, because let's say it was the kitten face, I'll say, "Great." But where was it located on the screen? And you have to try and position it in terms of its geographical location, and so we can measure your memory accuracy for the object and also where it was in space. But here's the fun thing during that learning, and I'm going to teach you 100 objects, you're going to have to try and learn a hundred of those objects for those. For every one of those objects, when I show it to you on the screen, I'm going to play a sound, so I show you the cat face and there's a meow.

Jordan Harbinger: [01:03:23] Yeah, that make sense.

Matthew Walker: [01:03:24] I show you the sound of a fire engine, I play the bell. I show you the sound of the cattle and sorry, I show you the kettle, you hear the sound of it whistling. But here's the fun thing. As you go into the stage of sleep, that cements those memories at night, which is called deep slow wave sleep or the deepest stages of non REM sleep. For half of those things that I showed you, I'm going to replay those sounds whilst you're asleep. Now it's at a level that won't wake you up, but those sounds still penetrate your brain and they get into the brain and they basically just tickle an unlock those memories, and they force those memories greater priority in the rank ordering list of being cemented and strengthened in the brain. So it's almost like I'm triggering your brain to replay those memories more strongly at night. How do I know that has a benefit? Well, the next day I come back and I test you on all 100 of those items. And what I find is that those items that I replayed during your sleep are remembered at twice the degree of recall.

Jordan Harbinger: [01:04:27] Wow.

Matthew Walker: [01:04:27] Double the memory benefit than those that you still slept on, but I did not replay. So you can imagine now trying to hack the system where when you're studying, you're playing your favorite playlist and then when you go to sleep at night, you play it at a lower level and you are replaying the specific information. Is that possible? We've done an experiment.

Jordan Harbinger: [01:04:51] Correct.

Matthew Walker: [01:04:51] I don't know about the playlist thing. It's probably just going to disrupt your sleep and you shouldn't do it. But is there a black mirror episode waiting? Yes, probably.

Jordan Harbinger: [01:04:58] Yes, yeah, that's really, really interesting. Why do we dream? I know that in Why We Sleep. You mentioned that memories and things like that are kind of encoded in the brain during REM sleep. There's also this sort of cleaning of the brain between neurons that happens when we're getting certain types of sleep and things like that where we maybe clear out amyloid plaques and things like that.

Matthew Walker: [01:05:20] Yeah, we wash away Alzheimer's disease essentially.

Jordan Harbinger: [01:05:22] Yeah, but what else is going on here? What's going on in our dreams? I mean, it's such a weird thing. I don't get what they're for. They seem like they're really long. Even though it's only been four minutes when I wake up. Other people are walking around, sleepwalking and dreaming at the same time. Like what? What the heck? This is the weirdest thing that humans do.

Matthew Walker: [01:05:39] It is weird. And when you think about it, everyone who slept last night, you all became flagrantly psychotic. And before you dismiss my diagnosis of your nightly psychosis, let me give you five good reasons. Firstly, last night when you were dreaming, you started to see things which were not there. So you were hallucinating, you believe things that couldn't possibly be true. So you were delusional. Third, you became confused about time, place, and person. You're suffering from disorientation. Fourth, you had wildly fluctuating emotions. Something that psychiatrists call being affectively labile, and then how wonderful, you wake up this morning and you forget most if not all of that dream experience. So you're suffering from amnesia.

Jordan Harbinger: [01:06:20] I remember a ton of my dreams, but it's not a good thing. People are always jealous and I'm like, "No, you don't need to remember that you are in a flying submarine transporting cocaine with Vanna White. There's no marginal benefits in my life.

Matthew Walker: [01:06:32] Those are the nightmare episodes right there as well. So firstly, dreams are just so peculiar when you realize that, but for both psychological and biological reasons, that state seems to be actually optimal. What we've discovered is that dreaming serves at least two different functions for the brain. The first is creativity. That during deep sleep is when we cement those individual memories. That's the hitting the save button sort of function. That's deep sleep. However, REM sleep then takes those newly freshly minted memories in the brain and starts to collide them with all of the back catalog of information that you've got stored up. It's almost like memory pinball. It's sort of, I don't know, it's like group therapy for memories where all of these memories get a name badge and during dream sleep they all get to speak with each other and they all find these new connections and new associations so that when you wake up the next day, you have a revised mind wide web of associations, and new associative network or rebooted iOS that is capable of dividing remarkable insights into previously impenetrable problems. And it is the reason that you have never been told to stay awake on a problem. Instead you're told to sleep on a problem.

Jordan Harbinger: [01:08:00] Sure, yeah. Good point.

Matthew Walker: [01:08:01] And in every language that I've studied to date from English to Swahili, that phrase or something like it actually seems to exist. In other words, the creative benefit of dream sleep transcends cultural boundaries. I should note by the way, that the French translation I think is much closer to you sleep with a problem, whereas the British, we say you sleep on a problem, French asleep with a problem.

Jordan Harbinger: [01:08:25] Yeah, the French or kinkier.

Matthew Walker: [01:08:26] So much about the romantic difference between the British and French.

Jordan Harbinger: [01:08:29] Absolutely, yeah.

Matthew Walker: [01:08:31] So that's the first benefit of dream sleep, but it's about an associative memory processing. It's about creating — understanding the statistical rules in which this world we live in operates and coming up with sort of novel solutions and sort of a creative connection building. It's the difference between wisdom versus knowledge. Knowledge is what you get from deep non-REM sleep remaining, sorry, retaining facts. Wisdom is what you get from REM sleep, which is what happens when you fit it all together. The other function of dream sleep though is emotional first aid.

Jordan Harbinger: [01:09:10] Yeah, that I found extremely interesting as well.

Matthew Walker: [01:09:14] Yeah, and we've done now a lot of this work. So I put forward a theory back in 2009, that it's during dream sleep. It is the only time during the 24 hour period where the brain, when you look at the chemistry of sleep, the brain shuts off a stress related chemical called noradrenaline in the brain or norepinephrine. The homolog of that in your body, everyone knows, which is called adrenaline or epinephrine, but in the brain it's called noradrenaline. That chemical is shut off during dream sleep, which means that your brain is devoid of this stress chemistry. And then when we were looking at people inside an MRI scanner, when they went into dream sleep, what we noticed is that the emotional centers of the brain and the memory centers of the brain, they reignite, they're actually up to 30 percent more active than when you're awake, which is stunning.

Jordan Harbinger: [01:10:06] Yeah.

Matthew Walker: [01:10:07] So what this meant to me or suggested to me, however, is that you have this brain that can reactivate and reprocess the emotional experiences of the prior day, but do so in a neural chemical state, but is quote unquote safe that is devoid of their stress free neurochemistry. So that in other words, the brain could actually strip away the painful sting from those emotional memories. Ao that when you woke up the next day, yes, you still remember those emotional memories better, but you are left with a memory of an emotional event, but is no longer sell itself emotional.

Jordan Harbinger: [01:10:46] It's almost like having a sparring partner where they're going to hit you sometimes, but they're not going to knock your head off. It's just like, "Oh, I'm dealing with this. I'm working this out." Okay, I've got to keep my guard up on my right side, but you're not getting hammered with a right cross every single time you drop your guard. Your brain is just working through these issues without your hormones making you go crazy. But what's happening when we do have a physical response, sometimes we wake up sweaty, you know we're going wake up in a fit of whatever you could get these people at night or whatever. What's going on there? Obviously, they're having some kind of crazy physical response.

Matthew Walker: [01:11:18] They are having a physical response, but typically those nighttime sweats do not occur during REM sleep. They actually occur from non-rapid eye movement sleep and people usually have what are called night terrors, which is where they wake up like a bolt and the heart is racing. They have terrible anxiety. They don't remember anything. They don't remember dreaming. The reason is because they weren't in dream sleep. They were in deep non-REM sleep. So that thing about in the movies where people wake up sweating the sort of racing and then they say, "I had a terrible dream." That's actually not true.

Jordan Harbinger: [01:11:50] It's like, “No, that comes later.” [indiscernible] [01:11:52] phase, nice try.

Matthew Walker: [01:11:52] Exactly. But it's during REM sleep that you are essentially divorcing the emotion from the memory. It's almost — it's emotional, I think it's emotional therapy. It's overnight therapy is what I would describe it as. So that we know is a function. We, the one clinical condition where we see that fail is in PTSD or post-traumatic stress disorder. That's where those people seem to have repetitive nightmares and I don't think it's a coincidence that they're having repetitive nightmares. If you look at those individuals, that chemical noradrenaline is in too high amounts. And I published theory 2009, we did a whole bunch of experiments to demonstrate that in fact, that's exactly what REM sleep was doing which was, it was divorcing the emotion from the memory. It was kind of peeling the bitter rind from the informational orange of emotional memories. And then a wonderful psychiatrist, Murray Raskind up in Seattle. He started to treat PTSD patients with a drug that would try to lower down that excessive level of noradrenaline in PTSD patients to try to bring it back down to a level that would be normal based on this overnight therapy theory that we'd published. And low and behold, those patients stopped having nightmares and they had clinical remission to some of their PTSD and it's now and wonderfully humbled, it is now the only or one of the only drugs that is prescribed for vets in the VA system for nightmares and PTSD.

Jordan Harbinger: [01:13:22] I know that we're coming up on time here, but one last point, which I thought was extremely fascinating really, was that we lose our ability if we get — if we lack REM sleep, our brains ability to decode emotions actually goes way down. What's going on here? That's kind of scary because it's kind of like saying, "Well, if you're under-rested, you're going to trust a con man or get in the car with a crazy stranger or choose poorly when it comes to friends or there's all kinds of things that could go wrong here.

Matthew Walker: [01:13:52] Yeah, and so this was a study that we just recently published about 18 months ago looking at a new function of REM sleep, which is actually the re-calibration of your emotional networks within the brain. So our brains have a vast amount of them dedicated to emotion processing, and emotions are critical, they convey all sorts of information consciously, non-consciously, and your ability, your EQ is just as important as your IQ. Your emotional intelligence is EQ. One of the components of EQ is to be able to accurately read the emotions of other people. Most of that comes from the face. Some of that comes from the voice. Other aspects come from movement. Some of it comes from touch. Most of it in us primate species comes from the face. So being able to accurately identify emotional facial expressions is critical. A good demonstration of when it fails is people who have autism.

[01:14:48] Now what we discovered is that when you have a full eight hours of sleep, you have a beautifully kind of tuned curve for picking up and discriminating subtle emotions. But when you suffer sleep deprivation, particularly a lack of REM sleep, that tuning curve, that ability to accurately separate friend from foe, and recognize those signals becomes blunted. So you can't accurately discriminate facial expressions. So you are at an evolutionary disadvantage. Now that runs through to things like business for example, because you're constantly looking for people and looking for these signs. Are they on board with me? Do they understand me? Do they not like me? Are they warming to me? All of these things are critical. Same goes for relationships. Think about the conditions where emotional intelligence and facial recognition is critical, yet they are under slept. Medicine, military, new parents, all of these are circumstances where that function is absolutely vital, but it goes away because of the chronic sleep deprivation that they are put under.

Jordan Harbinger: [01:15:54] Well, that's a little bit terrifying. The hardest work —

Matthew Walker: [01:15:57] You're welcome.

Jordan Harbinger: [01:15:57] Let's say the people who are keeping us safe, the hardest workers among us are the people that have the least amount of sleep and are rapidly decreasing in their ability to do what they do best, which is kind of scary. So it really does sort of say, "Hey, if you're in an important position, maybe start treating your sleep more seriously." And that was the overall message I got from the book, which is we're all — almost all of us are kind of chronically under slept and it's not this badge of honor that we should be wearing. It's actually hurting us in our creative pursuits, in our work, in the way that we relate to others. And at the end of this episode, I did have this huge checklist of things I wanted to cover, but we're going to end up throwing them in the worksheet. We do worksheets for every episode. There's a getting better sleep checklist, limiting blue light, where to get blue blockers, not drinking alcohol, the half-life of caffeine, a lot of these alcohol and sleep, the CPT eyes stuff.

Matthew Walker: [01:16:48] Temperature of darkness.

Jordan Harbinger: [01:16:49] All that stuff.

Matthew Walker: [01:16:50] Towards entrepreneurial society. Drop your temperature at night. Regularity, if I was going to give you one piece of advice, go to bed at the same time, wake up at the same time, no matter whether it's the day or you've had a bad night of sleep or even if it's the weekend, regularity is key.

Jordan Harbinger: [01:17:05] That's great. Yeah, we'LevelOne Course throw that in the checklist. So for the worksheets, which are always in the show notes for the episode, we will have everything from caffeine to temperature to blue blockers and a how to nap properly.

Matthew Walker: [01:17:15] Brilliant. Jordan, you are sleep ambassador now.

Jordan Harbinger: [01:17:18] That's right.

Matthew Walker: [01:17:18] Wonderful.

Jordan Harbinger: [01:17:19] That's right. Somebody has got to do it because we've been taught our whole lives that getting enough sleep is for wimps or a luxury that you can only have on Saturday, right?

Matthew Walker: [01:17:29] It is. It is a huge problem. The stigma that we've labeled sleep with, which is laziness, slothful. Sleep is not an optional lifestyle luxury. Sleep is a non-negotiable biological necessity. Sleep has a life support system I would say, and it is mother nature's best effort yet at immortality, and the decimation of sleep throughout industrialized nations is now having a catastrophic impact on our health, our wellness as well as the safety and the education of our children. It is a silent sleep loss epidemic and I would contend that it is fast becoming the greatest public health challenge that we now face in the 21st century.

Jordan Harbinger: [01:18:09] Matt, thank you very much. Dr. Matt, thank you very much.

Matthew Walker: [01:18:12] You're welcome. Thank you, and sleep well.

Jordan Harbinger: [01:18:16] So Jason, I know I didn't want to do one on sleep, but I did this one on sleep, but I'm glad that I did because I thought this was really something special.

Jason DeFillippo: [01:18:24]  Matt's book really kind of got me thinking more and more about how I need to get my sleep game on. I've been using a sleep tracker for my Apple watch and now I bit the bullet and I got the new aura ring. So now I can really see what's happening to me at night because the data seems far, far superior than the Apple watch. You have one of these two, don't you?

Jordan Harbinger: [01:18:43] I do, but I don't really know how to use it. I just look at my sleep score and I'm like, "Uh, okay. It says take it easy." I'll take it easy then.

Jason DeFillippo: [01:18:50] I just track it over time. So there's a graph where you can see how your score is over time and I can say, "Oh, it's been going down. What have I been doing wrong before I go to bed?" Or like, am I stressed or have I like stayed up too late? Did I have too many beers or what it is? And then I can adjust the next day for it. It is really — it's really helping me a lot, like kind of get down to it because his book was fantastic and it really got me thinking.

Jordan Harbinger: [01:19:12] Yeah, there's a lot in here about sleep, sleep habits, sleep management. I tried to get into as much of that as I could today for practicality and so I think we did a decent job there. I think we got a lot of really useful stuff. Great big thank you to Matthew Walker. The book title is Why We Sleep, and if you want to know how I managed to book all these amazing guests and manage my relationships using systems and tiny habits, I want to teach you those systems and those tiny habits in just a few minutes per day. Check out our Six-Minute Networking Course. It's free over at jordanharbinger.com/course. Go there and do it now. It's not the kind of thing you can make up for lost time. Relationships are all about digging the well before you get thirsty, so check us out and learn the ropes that I wish I knew 10, 15 years ago at jordanharbinger.com/course.

[01:20:01] Speaking to building relationships, shoot me a takeaway here from Matthew Walker. I'm @jordanharbinger on both Twitter and Instagram, and I love hearing from you on both platforms. And don't forget, if you want to learn how to apply everything you heard today from Matthew Walker, make sure you go grab those worksheets. Also in the show notes at jordanharbinger.com/podcast.

[01:20:20] This show is produced in association with PodcastOne and this episode was co-produced by Jason "The Somnambulist" DeFillippo and Jen Harbinger. Show notes are by Robert Fogarty. Worksheets by Caleb Bacon, and I'm your host, Jordan Harbinger. The fee for the show is that you share it with friends when you find something useful, which is hopefully in every single episode. So please share the show with those you love and even those you don't. We've got a lot of great stuff in the pipeline. I'm very excited to hear what you all think about it. In the meantime, do your best to apply what you hear on the show so you can live what you listen, and we'll see you next time.