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The Joe Rogan ExperienceThe Joe Rogan Experience

Joe Rogan Experience #1109 - Matthew Walker

Matthew Walker is Professor of Neuroscience and Psychology at the University of California, Berkeley, and Founder and Director of the Center for Human Sleep Science. Check out his book "Why We Sleep: Unlocking the Power of Sleep and Dreams" on Amazon. https://www.amazon.com/dp/1501144316

Joe RoganhostMatthew Walkerguest
Apr 25, 20181h 55mWatch on YouTube ↗

EVERY SPOKEN WORD

  1. 0:06 – 1:34

    Sleeping in hotels: the “first-night effect” and half-awake brains

    1. JR

      And we're live. What's going on, mate? Did you sleep well last night?

    2. MW

      I did.

    3. JR

      (laughs)

    4. MW

      I didn't sleep too badly. Uh, I mean, hotels are a tough thing. Um, and we actually know the science that, um, one-half of your brain will actually not sleep as deeply than the other when you're sleeping in a, an unusual room like a hotel room.

    5. JR

      Really? That's what fucks me up.

    6. MW

      Yeah.

    7. JR

      'Cause when I'm on the road, you know, I'll do three different hotels in a week 'cause I'll do like, a Thursday, Friday, Saturday like, with gigs, and then by the time Sunday rolls around, I'm a mess.

    8. MW

      In rough shape?

    9. JR

      Yeah.

    10. MW

      Yeah.

    11. JR

      Is that what it is?

    12. MW

      Yeah. And it's a, you know, it's a threat detection thing that-

    13. JR

      Ah.

    14. MW

      Um, I mean if you look at other species, they can do this much more impressively than we can. So dolphins or any sort of sea-dwelling mammal can actually sleep with half a brain. So one-half of their brain goes into deep sleep. The other half is wide awake.

    15. JR

      That's how people at the DMV do it, those people that work at the Department of Motor Vehicles.

    16. MW

      (laughs)

    17. JR

      They're, they're, they work half asleep. You ever meet 'em?

    18. MW

      I haven't, no. But-

    19. JR

      Just, just teasing you.

    20. MW

      I will, I, I, I-

    21. JR

      If you're DMV listening going, "Fuck you, man. Next time you come in to get your license renewed."

    22. MW

      There's my next NIH grant, I think, uh, looking at the DMV and sleep. But yeah, we-

    23. JR

      TSA workers, same thing, same-

    24. MW

      Same, same type of human.

    25. JR

      That, I've come across.

    26. MW

      Ah.

    27. JR

      Yeah. Them too. I'm just kidding, fuckers. Relax. Um, so when you're in a hotel room, what is happening that your half your brain is not really sleeping?

  2. 1:34 – 3:16

    Sleep architecture 101: non-REM vs REM and why quality matters

    1. MW

      Yeah, so there's different stages of sleep. There are two principle types. One is non-rapid eye movement sleep, or non-REM sleep. The other is REM sleep, uh, which is also known as dream sleep.

    2. JR

      Right.

    3. MW

      Um, and non-rapid eye movement sleep is further divided into four separate stages, um, which are unimaginatively called stages one through four. (laughs) We're a creative bunch as-

    4. JR

      It's easy to remember.

    5. MW

      ... as, researchers. It is true. Uh, but I think it's also our low IQ. But it's the deep stages of sleep, three and four of that non-rapid eye movement, that's where a lot of sort of body replenishment takes place-

    6. JR

      Mm-hmm.

    7. MW

      ... great for the cardiovascular system, metabolism, all of those good things. But that's the deep sleep that one-half of your brain will resist going into when you're sleeping in a foreign environment.

    8. JR

      Ah.

    9. MW

      So it stays in this kind of lighter stage, almost like a threat detection system.

    10. JR

      Right.

    11. MW

      Um, and you can imagine why, you know?

    12. JR

      Yeah.

    13. MW

      It's an unusual context. Evolutionarily, it would make a lot of sense to just have that sort of on guard one-half of the brain.

    14. JR

      That makes so much sense.

    15. MW

      Um-

    16. JR

      And that, that, that really, for me, it fills in the blanks of like, why even if I get, you know, seven, eight hours sleep on the road, I'm still kind of just out of it.

    17. MW

      Yeah, and that's in fact probably one of the, I think the most impressive parts of, um, new research on sleep. It's not just about quantity. It's also about quality.

    18. JR

      Mm-hmm.

    19. MW

      And quality can be as detrimental if you don't get it as a reduction in total quality. I mean, both are essential.

    20. JR

      Right.

    21. MW

      But I think it speaks exactly to your point. You just don't feel like it's a refreshing sort of deep sleep. Um-

    22. JR

      Yeah, it feels totally different. Um, it just, it feels like, I guess I would say it feels like half asleep.

    23. MW

      Yeah.

    24. JR

      I mean, (laughs) it's really kinda how it does feel.

    25. MW

      (laughs) Yeah.

  3. 3:16 – 6:39

    Alcohol, cannabis, and REM suppression: why vivid dreams rebound when you quit

    1. JR

      Um, one of the things that I noticed, I did this thing with my friends called Sober October where we, um, we didn't smoke any pot or do any, no drinking at all, nothing for, for a month. And, uh, when I did it, one of the things I found was that after about, I don't know how many days, but it was noticeable that I would have these incredibly vivid dreams. And then I had read that marijuana does something to suppress heavy REM sleep. Like, what, what, what is happening there?

    2. MW

      Yeah, so both of those chemicals, both of which are used as a sleep aid, alcohol and marijuana, are actually very good at blocking your dream sleep, your rapid eye movement sleep. And so what happens is that the brain is quite clever in this regard. It builds up a clock counter of how much dream sleep you should've had but have not been getting.

    3. JR

      Whoa.

    4. MW

      And it starts to develop this increasing appetite and hunger for dream sleep so that finally when the alcohol actually gets out of your system, Sober October-

    5. JR

      Yeah.

    6. MW

      ... love the, love the name, um, that's all of a sudden where you get what's called a REM sleep rebound effect where you not only get the normal amount of REM sleep that you would normally have. You get that, plus the brain tries to get back some of that dream sleep that it's been losing over the past maybe 11, (laughs) 11 months. Um, so you get this-

    7. JR

      Try 20 years. (laughs)

    8. MW

      (laughs) Yeah, I didn't wanna make any assumptions, um, uh, so, um, so you get this REM sleep rebound effect, and that's where you have these really intense dream sleep, um, situations.

    9. JR

      Yeah.

    10. MW

      It's the same reason that people, they'll say like, "I had a bit too much to drink last night." Maybe it was a Friday, a Saturday. They sleep in late and they say, "I just had these crazy dreams."

    11. JR

      Mm-hmm.

    12. MW

      What happens there is a kind of an acute version where the alcohol is swilling around in your system and after about six hours, your liver and your kidneys have finally excreted all of the alcohol and your brain has been deprived of dream sleep for that first six hours. So then it feasts-

    13. JR

      Mm-hmm.

    14. MW

      ... in the last couple of hours, and that's why you have these really bizarre dreams after you've been drinking a little bit too much.

    15. JR

      Oh, wow. So wha- what is happening with marijuana though specifically? Do you know?

    16. MW

      Yeah, so marijuana, um, it, it does help people... well, help, it, it puts people to sleep quicker, although I think that the question is whether it's really naturalistic sleep or not that they go into. Certainly with alcohol, it's not. Um, that nightcap idea is, is a misnomer.... alcohol will actually, well, it's a form of drugs that we call the sedatives. And sedation is not sleep, it's very different, but we often mistake one for the other.

    17. JR

      Mm-hmm.

    18. MW

      Marijuana seems to act in a physiologically very different way, it doesn't target the same receptors in the brain. So it's unclear whether the speed with which you fall asleep after, um, having a session with marijuana is actually natural sleep. Let's assume it is. The problem however is that it then will start to disrupt REM sleep, it will start to block the process we think perhaps at the level of the brainstem, which is where these two types of sleep, non-REM and REM sleep, will actually get sort of worked out. That's where marijuana may actually impact dream sleep and shut it down and block it.

    19. JR

      Have there been any studies on chronic marijuana smokers, like those, uh, dawn to dusk type characters that just are constantly high? Like, and what happens to their brain from not... 'Cause they must never h- hit REM sleep.

  4. 6:39 – 12:45

    REM deprivation extremes: delirium tremens and dreaming while awake

    1. MW

      Yeah. So people haven't looked at marijuana, they have looked at alcohol though.

    2. JR

      Hmm.

    3. MW

      Exactly that. So what happens is if you look at alcoholics, um, they will have something often when they, um, come off alcohol, something called delirium tremens, which is where the sort of DT. Um, there what happens is that the alcohol has been blocking dream sleep for so long and the pressure for dream sleep is built up so powerfully in the brain, it actually just spills over into wakefulness.

    4. JR

      Whoa.

    5. MW

      And so the brain just says, "Look, okay, if I'm not going to get this dream sleep whilst you're asleep, I'm just going to take it whilst you're awake."

    6. JR

      (laughs)

    7. MW

      And so you start to essentially dream while you're awake. It's this sort of collision of two states of consciousness, so you get delirium.

    8. JR

      Wow! I always thought that DTs were detoxing, like when someone says someone's going through DTs.

    9. MW

      Oh, they're... Okay, yeah.

    10. JR

      So it's delirium tremor, that's what you're talking-

    11. MW

      Yeah, delirium tremens, yeah-

    12. JR

      Tremens.

    13. MW

      ... sort of...

    14. JR

      Mm. So w- like, what is going on with them when this is happening? So if they are going through this delirium during the day while they're conscious, what- what's physiologically happening?

    15. MW

      So it's almost as though the veil of REM sleep gets pulled over the waking brain as it were-

    16. JR

      (laughs)

    17. MW

      ... so you have this mixed state of consciousness that you can pick-

    18. JR

      Wow.

    19. MW

      ... up with brain wave recordings. Um-

    20. JR

      Wow.

    21. MW

      And it just tells me, I mean, a- in some ways how necessary sleep must be.

    22. JR

      Mm-hmm.

    23. MW

      If that's the lengths that the brain will go to get that which it's been missing-

    24. JR

      Yeah.

    25. MW

      ... it just shows you um, why, you know, it took mother nature 3.6 million years to put this thing called an eight hour sleep necessity in place, um, and we've come along and within the space of 100 years, we've lopped off almost 20% of that if you look at the data.

    26. JR

      Wow, really?

    27. MW

      Yeah.

    28. JR

      (sighs) And so many people take pride in that too, "I don't need eight hour sleep. I got three, I'm good, ready to go, kick ass and dominate the world."

    29. MW

      Yeah.

    30. JR

      Yeah.

  5. 12:45 – 14:26

    Why dreams feel psychedelic: brain activity patterns during REM

    1. JR

      What is happening when you're having these s- s- uh, hallucinogenic experiences? Like, what are the chemicals that are causing it? Do we know?

    2. MW

      We do, yeah.

    3. JR

      Yeah?

    4. MW

      And we- so we've done some of these studies where we put people into brain scanners, we let them fall asleep, and then we see what happens within the brain, which parts of the brain are switching on, which parts of the brain are switching off. When you go into REM sleep, firstly, some parts of your brain become, um, 30% more active than when you're awake. So-

    5. JR

      Whoa.

    6. MW

      ... it's- you know, we think of sleep as this sort of, you know, static, passive state where everything just kind of drops down in terms of activity. Quite the contrary. But what's also interesting is that not all parts of the brain ramp up when you go into REM sleep. Visual parts of the brain increase, motor parts of the brain increase, emotional centers and memory centers, they all increase. But the part of the brain that bucks the trend and goes in the opposite direction is the part of the brain that we call the prefrontal cortex, this sort of CEO of the brain that's very good at rational, logical thinking. That parts of- that part of the brain gets shut off. So it's almost as though, you know, the- the prison guards are gone and everyone runs amok-

    7. JR

      (laughs)

    8. MW

      ... because there's no controller, you know-

    9. JR

      Wow.

    10. MW

      ... in place. And so we know sort of from the patterns of brain activity why you become sort of so visual, you see things, why you have motor kinesthetic activity, why things feel so emotional, but also why things seem utterly illogical and irrational 'cause your frontal brain, the thing that makes us most human, you can say goodbye to that for the rest of dream sleep.

    11. JR

      So there's no driver?

    12. MW

      So there's no driver. Yeah.

  6. 14:26 – 28:21

    Why we forget dreams: ‘availability vs accessibility’ and REM brain chemistry

    1. JR

      Wow. Now, why do we forget? Why do we forget those dreams? Because I- I wake up and I am sure that I'm gonna remember these dreams. And sometimes I do, sometimes I remember, and I don't think I really remember them. I think what it is is very much like, you ever hear someone talk about a memory from a long time ago? I used to think that people actually remembered things from a long time ago, but now what I think is they remember remembering it.

    2. MW

      Mm-hmm.

    3. JR

      I think they remember talking about it, they remember how they described it, and then they sort of remember that and repeat it and in their mind convince themselves that that's what happened. Because I've heard people tell stories about the past and they're- they vary wildly from what is absolutely true, like- like factual, you could check it, you could research it, you know what the facts are. But in their mind, it's very different. And I think that it's entirely possible that what people are doing is remembering the recollection of these memories and how they told them, and then also sort of people elaborate things to make themselves look better or make the situation look more dramatic. But with dreams, that doesn't make any sense. So I was o- I'm always trying to figure out, like, what is it about a dream where sometimes I can remember the dream, and sometimes it's so vivid when I wake up, I'm like, "Holy shit-"

    4. MW

      (laughs)

    5. JR

      "... that was crazy. What a dream." And then I forget it 20 minutes later.

    6. MW

      Right.

    7. JR

      What is that?

    8. MW

      So firstly, I mean, one theory of dreaming is that it's just simply a reconstruction when you wake up. So you have these-

    9. JR

      Mm-hmm.

    10. MW

      ... fragments of activity and what your cortex does when it wakes up is what your cortex is designed to do when you're awake normally, which is try to package everything and make a good story, make logical fit out of the world. That's one theory. I- I don't believe that, though. Um, your- your point is a really interesting one. Do I remember my dreams? Um, that doesn't necessarily mean I forget my dreams. And what I mean by that is accessibility versus availability. So have you ever had-

    11. JR

      Mm-hmm.

    12. MW

      ... that experience where you've woken up, you thought, "I was definitely dreaming. I can't quite grab it," you know, it just- and it's gone.

    13. JR

      Mm-hmm.

    14. MW

      And then two days later, you're in the shower, you're sort of washing yourself, you see a bottle of shampoo, you see the label, and it just triggers the unlocking of that dream memory and it sort of comes flooding back.

    15. JR

      Mm-hmm.

    16. MW

      Or someone says something to you and you think, "Oh, that was the dream."

    17. JR

      Yeah.

    18. MW

      What that tells me as a brain scientist is that the memory is there, it's preserved, it's available, but what happens when- m- most of the time when we wake up is that we lose the IP address to the memory.

    19. JR

      Oh.

    20. MW

      So it's present, but it's not consciously accessible. Available, not accessible. If that's true, what it means is that this type of information we know can have non-conscious impacts on our behavior all the time. There's great brain science about this non-conscious memory processing. It's possible that we store every one of our dreams, we just don't consciously have accessibility to it. But nevertheless, it's changing how we behave, how we feel each and every day. No evidence for it. It's a theory I'm still wanting to test. But that's possible, too. And it's only that anecdote where I can think, "I just don't remember the dream. I've forgotten it." I don't think that may be true. It may still be there, I just need to find the keys to a- sort of access that memory.

    21. JR

      What's stunning to me is how quickly the dream evaporates, the memory of the dream. W- uh, i- in relation to, uh, an actual experience. Like, if we went outside and we saw some lady walk up to some guy and kick him in the balls, we'd be like, "Whoa!" We would remember that.... and that you, you, you'd be able to tell your friends. Like, "Yeah, some lady just randomly walked up to some guy and kicked him in the balls."

    22. MW

      (laughs)

    23. JR

      Like, we would remember that. And you would remember it 10 minutes later, you'd remember it in an hour, you'd remember it yes- next day, you'd, you'd be telling your friends. "Yeah, she just walked right up to him. I remember it like it was yesterday." 'Cause it was, right?

    24. MW

      Yeah.

    25. JR

      But a dream can be 10 minutes ago, and you wake up and, "Dude, it was King Kong and he was, he was swinging from my ceiling. And somehow or another he, he fit in the room, but the room got bigger." And you, you have these crazy dreams, and then 20 minutes later, you forget all of it. Like, what is happening there?

    26. MW

      So one, one current explanation is that the chemistry of the brain when you go into dream sleep is radically different.

    27. JR

      Yeah.

    28. MW

      So one of the chemicals called noradrenaline in the brain, which downstairs in the body, its sister chemical is called adrenaline. Noradrenaline actually plummets to the lowest levels. It's actually, it's a stress chemical in the brain, or it's one of them. That gets shut off during dream sleep, which is-

    29. JR

      Even if you're panicking?

    30. MW

      ... remarkable.

  7. 28:21 – 33:05

    What REM does for the body and skills: paralysis, rehearsal, and performance gains

    1. JR

      Au contraire, potheads. Um, so what is happening to the body during REM sleep that's so critical, that one particular aspect of sleep?

    2. MW

      So firstly, in the body, the, your cardiovascular system seems to do something quite strange. It goes through periods of dramatic acceleration and then dramatic deceleration.

    3. JR

      During REM sleep?

    4. MW

      Up in ... Yeah, during REM sleep. Quite unpredictable too.

    5. JR

      Mm.

    6. MW

      We also know that during REM sleep, your brain paralyzes your body so that your mind can dream safely. So-

    7. JR

      Wow.

    8. MW

      ... s- y- I mean, and that makes a lot of, you know, sense if you're thinking that you're, you know, this world champion mixed martial arts person. And it's in the middle of the night, you're not ... It's dark, you can't see, you're not perceiving your outside world, you're going to get popped out of the gene pool very quickly if you start acting out that experience. So there is a barrier in place, that Mother Nature locks you down in incarceration, muscle incarcil- incarceration.

    9. JR

      That's crazy that you say that, because when I was fighting when I was young, I would wake up throwing kicks. I would kick in the middle of the night. I would do it all the time. I would be sleeping and I'd just ... I w- I would move and throw a kick in the middle of the night.

    10. MW

      Yeah.

    11. JR

      And I r- remember it waking me up like, "What the fuck is wrong with me?" And then I'd try to go back to sleep again. But I was obviously dreaming about competing.

    12. MW

      Do you actually remember this? So when you woke up, did you remember dreaming at that point, or did you just have no recollection of anything going on at that point?

    13. JR

      I, I believe I had a recollection. It's been a long time, but I believe I had a recollection. Um, like, I would be like in bed with my girlfriend and I'd wake her up too, you know, 'cause I'd just jolt.

    14. MW

      Right.

    15. JR

      Like I wouldn't throw a full kick, but my body would move like I was going to. You know, like I would turn my hips and my leg would extend. It was ... My body was ... It was ... I, I've, I attribute it to the, the idea that it's so extreme, like the activity of fighting is so extreme, that my, my m-... brain had kind of like hyper-charged itself to compete at this very high level, you know. And that this was like so unusual that it was, it was almost at red alert all the time and maybe even trying to work out patterns-

    16. MW

      Yep.

    17. JR

      ... while it was sleeping, yeah?

    18. MW

      That's exactly the evidence that we have now.

    19. JR

      Oh.

    20. MW

      So for things like motor skills or even rats running around a maze where they will learn specific sort of, you know, um, navigational pathways and even skilled motor movements. What you can do is you can place these electrodes into centers of the, of the brain. We, we work in a... My sleep, Sleep Center works on humans, but other people have done these, uh, studies in rats. And you implant electrodes and you measure the brain cells firing as the rat is running around the maze. And let's say that you can sort of play little tones for each brain cell. So they're running around the maze and, and you can listen to the brain cells learning the signature of that maze. So it goes (singing) . What was amazing is that when you let those rats sleep, but you keep listening to the brain, what you hear is (singing) as if the brain is actually, and in fact it is, it's replaying the exact same sequence, the memory sequence that it was learning whilst it was awake-

    21. JR

      Wow.

    22. MW

      ... it's replaying but at a speed that is 20 times faster.

    23. JR

      Whoa.

    24. MW

      So, you know, it, uh, now we start to get into this Inception world, and I don't mean to 'cause the scientific data, it really, uh, we're not sort of in that territory. But, you know, that notion of time compression and time dilation that Christopher Nolan played so well with in that-

    25. JR

      Mm-hmm.

    26. MW

      ... movie, we can see that at the level of brain cell firing in rats as they're learning these mazes. And it comes back to what you're saying, which is that the better that they rehearse those skilled memories, when you wake them up and test them the next day, that predicts how much better they are in terms of their performance. So it's not just that you learn, you go to sleep, and you replay, and you hit the save button on these n- new memories. You actually sculpt out those memories and you improve them. And we've done studies with motor skill learning, critical for athletic performance. And practice does not make perfect. Practice with a night of sleep is what makes perfect because you come back the next day and you're 20% to 30% better in terms of your skilled performance than where you were at the end of your practice session the day before.

    27. JR

      Wow! Wow.

    28. MW

      I mean, sleep is the greatest legal performance-enhancing drug that most people are probably neglecting in sport.

    29. JR

      Wow. And not just for your physical performance, but actually skill learning.

  8. 33:05 – 43:01

    Athletic fallout from short sleep: endurance, injury risk, and stability failures

    1. MW

      That's right. Skill learning, memory, and then also, you know, downstairs in the body, all of the recuperative benefits. Um, and you can flip the coin, by the way. If you're getting six hours of sleep or less, your time to physical exhaustion drops by s- up to 30%. So you could spend all of your time training for a 10-round fight, perfect condition, but then I put you on six hours of sleep the night before, you're now gonna be physically exhausted by round seven rather than round 10.

    2. JR

      Wow. But, well, and that's a really hard thing for fighters 'cause they have a very difficult time sleeping the night before a big fight.

    3. MW

      Yeah.

    4. JR

      It's very, very difficult 'cause-

    5. MW

      Hugely problematic.

    6. JR

      ... there's anxiety and-

    7. MW

      Yep.

    8. JR

      ... and, uh, I would imagine it's gotta be... I mean, it's probably gonna take a t- a huge toll on them, and it's probably be a, a huge benefit if they can somehow or another bypass all that and just relax and learn how to relax and learn how to actually sleep.

    9. MW

      I mean, it's, I think, you know, it's one of... We're constantly trying to hack the physiological system, especially in elite sports these days 'cause, you know, small fractions of a percent of gain can make a huge difference.

    10. JR

      Well, that sounds like 30%.

    11. MW

      Sleep is-

    12. JR

      That's a monster.

    13. MW

      ... huge, yeah. I mean, your time to f- yeah, sort of not just physical exhaustion, but, you know, the lactic acid builds up quicker the less and less that you sleep. Your ability of the lungs to actually expire carbon dioxide and inhale oxygen decreases the less sleep that you have.

    14. JR

      Man, that makes so much sense. Uh, w- well, 'cause when I was doing, I was doing Fear Factor and I was doing standup comedy and then I was also doing another television show and I was doing jujitsu. I was ne- I never got eight hours sleep. I mostly got four, usually got four, and my cardio always sucked.

    15. MW

      Yeah.

    16. JR

      (laughs) It was always terrible. And I'd be like, "Why does my cardio suck? I work out so much." Like, that was probably what it was.

    17. MW

      Yeah, it's a huge part of the-

    18. JR

      Wow.

    19. MW

      ... equation.

    20. JR

      Now how many hours of sleep should you get?

    21. MW

      Somewhere between, (clears throat) excuse me, somewhere between seven to nine hours. Um-

    22. JR

      Mm-hmm.

    23. MW

      ... and once you get below seven hours of sleep, we can measure objective impairments in your brain and your body.

    24. JR

      I can show that in the last two days. And I can sha- b- show it because I basically did the same workout two days in a row. Um, the day before, (coughs) I had flown back from Boston, very tired, um, hung out with my kids all day, um, went to get some sleep, but then I had to do some stuff at like 2:00 in the morning, and, uh, I just ev- never really got good sleep. And then my youngest daughter got up at 5:00. She was crying. And then, uh, I eventually, my alarm went off at 8:00. So my, my sleep was like three, four hours. It was all screwy. And the night before was even less 'cause I had flown and I had to get up early for the flight and I tried to sleep on the plane, and I went running and I felt like dog shit.

    25. MW

      Yeah.

    26. JR

      And then during the day, I felt like dog shit. I just didn't have... Like as I was running, I just didn't have any extra gear. I was like, "Ugh." I did it, I pushed through it, but then it was over, I was like, "Oh." Well, last night, last night I slept seven and a half hours. I woke up today, lifted weights, ran. I ran, felt great, feel great now. Like, two days in difference, I mean, that's the difference. The difference is one day I got real sleep, one day I didn't. I did the exact same thing even more today. I did, I lifted weights today as well, and I just feel great. So I could see, I could see it physiologically in the d- the difference in my performance in 24 hours.

    27. MW

      Yeah. And that's noticeable. I mean, we see that too. You know, your, um, your-... peak muscle strength, your physical vertical jump height, and your peak running speed. All of those things correlate with sleep. The less that you have, the worse those outcomes are. Probably one of the most surprising factors, though, was injury risk. When they've looked at athletes across a season and they've just plotted, you know, how frequently will they get injured. And then they surveyed them, you know, "How much sleep were you getting?" And they bucketed them into sort of people who were getting nine hours, seven hours, six, five, four. And it's a perfect linear relationship. The less sleep that you have, higher your injury risk. So people getting nine hours versus five hours, there was almost a 60% increase in probability of injury risk during a season.

    28. JR

      Do you attribute that to exhaustion or do you attribute that to a lack of recovery from the previous night's workout? Is it a combination of those things? Is it exhaustion causing you to misstep perhaps and like twist an ankle or t- turn a knee?

    29. MW

      Yeah, it's all of those things.

    30. JR

      All those things, a combination.

  9. 43:01 – 46:47

    Sleep as problem-solving and creativity engine: ‘sleep on it,’ dreams, and famous examples

    1. JR

      I've heard that too with problems and that's why people say, "Sleep on it."

    2. MW

      Yeah. Yeah, you've never been told to stay awake on a problem. (laughs)

    3. JR

      (laughs)

    4. MW

      Um-

    5. JR

      Yeah, it's true, right?

    6. MW

      You know-

    7. JR

      I mean, sometimes when you're about to go to bed, it's almost overwhelming. You just can't concentrate on anything else but this problem, whatever it is. And then you go to sleep and you wake up in the morning, you're like, "Eh, it's all right."

    8. MW

      Yeah.

    9. JR

      "It's gonna be fine."

    10. MW

      Yeah.

    11. JR

      "I got it. I know what to do."

    12. MW

      And sleep's a dir-

    13. JR

      Yeah.

    14. MW

      You know, and there's lots of anecdotal evidence of sleep-inspired creativity and now the shifts to one of the benefits of dreaming, in fact. It's during dream sleep when we take all of the information that we've previously learned and we start to collide it with all of the new information that we've learned. It's, um, I mean, it's a little bit like group therapy for memories, you know? Everyone gets a name badge and you all get to speak to each other and the brain starts to seek out and test novel connections and new associations. So it's almost like informational alchemy and you wake up the next morning with a revised mind-wide web that is now capable of divining, you know, incredible solutions to previously impenetrable problems. And lots of anecdotes, you know, Dmitri Mendeleev came up with the periodic table of elements by way of dream-inspired insight. You know? Talk about a Herculean task, take all of the elements in the known universe and figure out a structure as to how they all fit together, off you go. His waking brain could not do it. His sleeping brain solved the problem.

    15. JR

      Whoa.

    16. MW

      And Einstein, by the way, oh, this is great. Einstein was suggested to be a short sleeper and we don't know if that's true, but even if he was, he was a habitual napper during the day. I've got some great pictures of him on his work bench and he used sleep ruthlessly as a tool for creativity and he would sit at his desk and he would have a sort of pad of paper and a pencil and he had a- a chair with armrests and he would pick up two steel ball bearings and take a metal saucepan and turn it upside down, place it underneath the arm of the chair and put the two steel bal- steel ball bearings in his hands then he would rest back and he would start to fall asleep. And so he didn't fall too far into sleep. What would happen is at some point, his muscle tone would relax, they would release the steel ball bearings, they would crash on the saucepan, wake him up and then he would write down all of the creative ideas that he was having.

    17. JR

      (laughs)

    18. MW

      Isn't that brilliant?

    19. JR

      Wow.

    20. MW

      So no wonder, yeah, you're never told to sort of stay awake on a problem and in every language that I've inquired about to date, um, French, Swahili, that phrase, sleeping on a problem, seems to exist which must mean that this benefit of dream sleep transcends cultural boundaries. I should note, um, I think it's important, that the French, the French translation is much closer to y- you sleep with a problem. We, the British, you say you sleep on a problem. The French, you say you sleep with a problem. I think it says so much about the romantic difference between the- the British and the French, you know? They're the sort of-

    21. JR

      Yeah, the French trying to fuck everything.

    22. MW

      (laughs)

    23. JR

      Trying to fuck their problems. (laughs)

    24. MW

      I'll lose my British passport for saying that, but that's okay. Uh-

    25. JR

      (laughs)

    26. MW

      (laughs)

    27. JR

      You won't. I will, but I won't either.

    28. MW

      (laughs)

    29. JR

      I think it's just a joke. Um, that's fascinating that Einstein figured that out too, that he literally had like a- a whole routine. That he would drop this ball, it would hit it, bang, and wake up and start writing, like-

    30. MW

      Self-medicating.

  10. 46:47 – 50:10

    Modern light, screens, and melatonin: how tech delays sleep and reduces REM

    1. MW

      ... uh, but... I mean, he has a lot to answer for, by the way, in terms of the way that we're sleeping. You know, he electri- he was the first person to electrify society.

    2. JR

      Ah.

    3. MW

      Not necessarily create the- the light bulb, but he really, you know, gave, shifted us from a point where now we controlled the night in terms of illumination and li-... We are a dark-deprived society in this modern era and that's one of the things that is keeping us awake at night, a lack of darkness.

    4. JR

      Yeah, not just that, but also our inability to see the stars anymore. The- the light pollution that we have at night. I think it's, I think it's a giant shift in perspective. Like, uh, have you ever, you ever been to a, uh, planetarium or, um, an observatory, like one of those, uh-

    5. MW

      Yeah.

    6. JR

      ... at night? Um, there's a Keck Observatory in Hawaii is a place I- I try to go to, uh, every year and it's- it's really stunning because it's very high up. I think the observatory is, it's somewha- it's somewhere more than 9,000 feet above sea level and then I think you go even further and then they have the telescopes, but you go to visitor's center and you go to the visitor's center and they have some tele- telescopes set up, but it's p- you actually drive through the clouds. So as you're driving up this mountain, we were bummed out, we're like, "Oh, it's cloudy, we might not be able to see anything." And then you drive through the clouds and then when you get through the clouds, you're like, "Holy shit."

    7. MW

      (laughs)

    8. JR

      And- and you, you feel like you're on a spaceship flying through space and this is what our ancestors saw every night when they went to sleep with a clear sky, they saw all the stars. They saw the full Milky Way, like this. And the way the Big Island has set up, they use diffused lighting all over the island ch- because of the Keck Observatory. So, you don't have the same level of light pollution that you have when you're in a normal city like Los Angeles, which is terrible. I mean, LA, if you look up, you see like one or two stars 'cause everything's lit up.

    9. MW

      Yeah.

    10. JR

      It's crazy bright. That, I think that perspective is, uh, that's a- a giant factor in the way human beings look at their relationship with the universe.... but I think that also just the light everywhere, constant light everywhere, that's gotta be a big factor in why people sleep so little. Right?

    11. MW

      Yeah. We know it is now. I mean, these studies have been done. You know, f- the first part is the external light, which is, you know, street lighting. You know, even if you've got curtains, that can still bleed through.

    12. JR

      Yeah.

    13. MW

      But then when you come into the home, you know, the invasion of light into the home by way of technology has been a big problem. Uh-

    14. JR

      People looking at their phones before they go to bed.

    15. MW

      F- well, firstly, yeah, th- I mean, the incandescent light bulb w- sort of was the start of it. Um-

    16. JR

      Mm-hmm.

    17. MW

      ... and light bulbs can suppress a hormone that's called melatonin. It's the hormone of darkness, and it tells your brain when it's dark and when it's time to sleep. But then you add into that screen usage.

    18. JR

      Mm-hmm.

    19. MW

      And they've done studies where, for example, um, you know, one hour of iPad reading versus just one hour of reading on a book, you know, in dim light. That one hour of iPad reading firstly delayed the release of this critical darkness hormone called melatonin by about three hours. So if you read f- on your iPad for an hour here in California, your melatonin peak is not going to arrive, I mean, somewhere in Hawaii time, in fact, it's three hours delayed.

    20. JR

      Wow.

    21. MW

      It's 50% less in terms of its peak, and furthermore, you don't get the same amount of REM sleep, and when you wake up the next morning, you don't feel as refreshed or restored by your sleep. Those studies have been done, too.

  11. 50:10 – 54:53

    Practical sleep toolkit: regularity, darkness, cool rooms, and hot baths (temperature hacks)

    1. JR

      Wow. What should someone do, um, if they have a hard time sleeping? Like say if you're a person who has insomnia, you have a hard time getting, getting to bed, you, you have a hard time staying asleep. When you wake up, you can't go back to bed.

    2. MW

      Yeah.

    3. JR

      Are there, are there strategies?

    4. MW

      There are. I mean, I think for most people, there are five things that you can do just out the gate to get better sleep. Regularity is probably the most important thing I can tell you. Go to bed at the same time, wake up at the same time, no matter whether it's the weekend, weekday, s- regularity is key. We've spoken about light. For example, when you, in the last hour before bed, try to stay away from screens, but also just switch off half the lights in the house.

    5. JR

      Mm-hmm.

    6. MW

      You would be surprised at how soporific that is. It really starts to sort of make you feel a bit more drowsy. They've done some great studies where they would take people out, you know, into the Rockies, no electric light, no electricity whatsoever, and they started to go to bed two hours earlier than their acclaimed natural bedtime.

    7. JR

      Hm.

    8. MW

      Wasn't just because they didn't have anything necessarily to do. It was that their melatonin was rising, you know, two hours earlier. So keep it dark. The third is probably keep it cool. Your brain actually needs to drop its temperature by about two to three degrees Fahrenheit to initiate sleep.

    9. JR

      Hm.

    10. MW

      And that's the reason that you will always find it easier to fall asleep in a room that's too cold than too hot. Uh-

    11. JR

      I've seen people use cold pads.

    12. MW

      Yeah.

    13. JR

      Have you seen those? Where you sleep on these cold pads?

    14. MW

      Yeah.

    15. JR

      What do you think of those?

    16. MW

      Yeah. I mean, th- their evidence is pretty good that cooling the body actually works. They've, um ... You know, in the book, I write about, uh, a, a series of studies where they had people in, it's almost like a wetsuit, but it has all of these veins running through it, and they could actually perfuse warm or cold water into any part of the body, hands, core of the body, feet. And so that you could exquisitely manipulate the temperature of any part of the body. And what they found is that they could effectively cool the body down and it instantaneously made people fall asleep faster, and it gave them deeper, deep non-REM sleep, that sort of restorative sleep for the body.

    17. JR

      Oh.

    18. MW

      So... And you can even look at studies where people sleep semi-naked, and that also seems to improve their sleep, and they get a little bit more deep sleep too. So cold is better. Th- the paradox here though is that you need to warm your feet and your hands to kind of charm the blood away from your core out to the surface and radiate that heat.

    19. JR

      Really?

    20. MW

      So yeah.

    21. JR

      So you should go to sleep with socks and gloves on?

    22. MW

      Yeah. Or better still, have a hot bath. Um, evidence here too, um, that I discuss where people say, "You know, I get out of a hot bath, I, I feel nice and toasty and relaxed, and that's why I fall asleep." It's the opposite. When you get into a bath, you get vasodilation. All ... You sort of get rosy cheeks, red skin. All of the blood rushes to the surface. You get out of the bath and you have this massive thermal dump of heat that just evacuates from the body. Your core body temperature plummets, and that's why you sleep better. So you can hack the system very easily.

    23. JR

      Wow. So your core body temperature plummets, and that's what makes you sleep easier.

    24. MW

      Yeah.

    25. JR

      That sounds so counterintuitive.

    26. MW

      Yeah.

    27. JR

      But it makes sense.

    28. MW

      And it makes sense because that's how we were designed. If you look at hunter-gatherer tribes whose way of life has not changed for thousands of years and you ask, "How do they sleep?" one of the things that seems to dictate their sleep is the rise and fall of temperature. You know, temperature is at, at, at its lowest in the d- nadir of the night, you know, 3:00 or 4:00 in the morning. And as that temperature, that climate temperature starts to drop, that's when they start to get drowsy, as if temperature is just sort of signaling to the brain, "Now it's time to sleep." So light as well as temperature are two key triggers to help you get better sleep. Um, if you look at those tribes, by the way, and when they go to sleep and they wake up, um, you know, they go to sleep probably at two hours after dusk, sort of 8:00 to 9:00 in the evening, wake up about half an hour or even an hour before dawn. It's the rise in temperature rather than light that triggers their awakening.

    29. JR

      Wow.

    30. MW

      Um, but there's a reason ... You know, th- have you ever thought about what the term midnight actually means? (laughs)

  12. 54:53 – 57:38

    Biphasic sleep and the afternoon dip: what’s biology vs culture

    1. MW

      That- that wasn't ... That is not how we were, you know, designed to sleep. And in fact, we may also be designed to sleep biphasically too. If you look at those hunter-gatherers, they don't sleep one long bout of eight hours at night.

    2. JR

      Yeah, I've heard this recently, that people ... That you should have two sleeps. The idea of two sleeps.

    3. MW

      Yeah, it's actually a little different than the idea of two sleeps. So, there was a time in sort of the Dickensian era where people would sleep for the first half of the night, maybe sort of four hours or so. Then they would wake up, they would socialize, they would eat.

    4. JR

      Meal.

    5. MW

      They would make love. And then they would go back and have a second sleep. If you look at natural biological rhythms in the brain and the body, that doesn't really seem to be how we were designed. It certainly seems to be something that we did in society, but I think it's more of a societal, um, trend than it was a biological edict. However, we do seem to have two sleep periods, the way that we were designed. Those tribes will often sleep about six and a half hours, seven hours of sleep at night. And then especially in the summer, they'll have that siesta-like behavior in the afternoon. And all of us have that, sort of this, what's called the postprandial dip in alertness. It just means after lunch. And if I measure your brain wave activity with electrodes, I can see a drop in your physiological alertness somewhere between 2:00 to 4:00 PM in the afternoon.

    6. JR

      But is that dependent on diet?

    7. MW

      It's not. People think it is, you know, especially after they've had a heavy lunch.

    8. JR

      Yeah.

    9. MW

      You can actually just have people fast and sort of ... Uh, well, fasting for long periods of time actually makes you sleep much worse. But, um, you can have people abstain from lunch and you still get that drop. So it's independent of food. It's a genetically hardwired pre-programmed drop that suggests we should be sleeping biphasically.

    10. JR

      But does ... Is that dependent upon their standard diet? Because if- if someone is on, uh, a carbohy- a c- carbohydrate-rich diet, a lot of times you do get that spike.

    11. MW

      Yeah.

    12. JR

      And then you crash.

    13. MW

      Crash.

    14. JR

      That's ... But when people are on low-carb and high-fat diets, they don't get that and they- they- they tend to be more even with their energy through the day.

    15. MW

      Yeah. So yeah, that sort of more constant release of energy can actually help you sort of almost combat that lull. But that-

    16. JR

      But that lull exists no matter what.

    17. MW

      Ex- exactly.

    18. JR

      So even if you don't think it exists, it's there.

    19. MW

      It's still present, yeah.

    20. JR

      Interesting. So why did they do that in the- the- the Dickens era? Why did they ... What- what ... Is there a root cause of their double sleep thing?

    21. MW

      We don't know. I mean, it's hard to sort of really go back. They-

    22. JR

      Fascinating.

    23. MW

      Yeah, it's incre-

    24. JR

      That was a trend.

    25. MW

      Yeah, that it was a movement.

    26. JR

      That they would just wake up and do things and ...

    27. MW

      Yeah.

    28. JR

      Maybe it's 'cause they didn't have TV.

    29. MW

      (laughs) Yeah.

    30. JR

      And they didn't know what to do with themselves.

  13. 57:38 – 1:03:18

    Sleep and disease risk: mortality, Alzheimer’s, cancer, obesity, and appetite hormones

    1. JR

      ... a lot of fascinating stuff came out of that time. Now, when you're, um, when- when you're measuring, uh, people's health, and when you're measuring people's health in regard to how much sleep they have, like what ... How do you- how do you do that? Do you just talk to people? Do you do surveys? Like, how do you get like a detailed analysis of people's patterns?

    2. MW

      So you can do it at many different levels. I mean, we can start at the sort of gross, high level, which is epidemiological studies across millions of people, where you do surveys, you ask them about their sleep, and then you look at health outcomes. The first thing from that data that's clear is an unfortunate truth. The shorter your sleep, the shorter your life.

    3. JR

      Whoa.

    4. MW

      Short sleep predicts all-cause mortality.

    5. JR

      Which is really ironic because people that wanna sleep less are like, "You know, I don't have a whole lotta time."

    6. MW

      Yeah.

    7. JR

      "You know, this life is short."

    8. MW

      Yes.

    9. JR

      Well, it's fucking shorter if you sleep less. (laughs)

    10. MW

      Yeah, that- that old maxim, you know, you can sleep when you're dead.

    11. JR

      Yeah.

    12. MW

      Well, it's mortally unwise advice because we know from the data you will be both dead sooner and the quality of that now shorter life will be significantly worse.

    13. JR

      Yeah, that's counterintuitive to people, the- the idea that you need this ... It's not just like you're making best use of time by sleeping less. You're not. You- you would make best use of time by being awake less.

    14. MW

      Exactly.

    15. JR

      Which is crazy.

    16. MW

      I mean, wakefulness, firstly, from a brain perspective, is low-level brain damage. We know that.

    17. JR

      Wakefulness is?

    18. MW

      Yeah.

    19. JR

      Low ... Like right now, we're- you and I are getting low-level brain damage.

    20. MW

      Yeah, that's right. And it's sleep that offers a reparatory function.

    21. JR

      Wow.

    22. MW

      And- and, you know, I'll give you one example, which is your risk for Alzheimer's disease. Insufficient sleep across the lifespan now seems to be one of the most significant lifestyle factors determining whether or not you'll develop Alzheimer's.

    23. JR

      What studies or, if any, have been done on people that work third shift?

    24. MW

      So people have looked at shift work in general. Um, they haven't necessarily split it down, uh, to that granular point. But, um, what we see is that shift workers have higher rates of obesity, higher rates of diabetes, but perhaps most frighteningly, cancer. And in fact, we now know the link between a lack of sleep and cancer, um, is quite strong. Insufficient sleep is linked to cancer of the bowel, cancer of the prostate, cancer of the breast. And the association has become so powerful that recently, the World Health Organization decided to classify any form of nighttime shift work as a probable carcinogen.

    25. JR

      Whoa.

    26. MW

      Yeah. So jobs that may induce cancer because of a disruption of your sleep-wake rhythms.

    27. JR

      Are there other correlating factors? Like, don't people that sleep less or work into the night, don't they eat more and eat more shitty food?

    28. MW

      They do both of those things.

    29. JR

      Yeah.

    30. MW

      Yeah. And we know exactly the pathways. So there are two hormones that control your appetite and your weight. Um, one is called leptin, the other is called ghrelin. Um, they sound like hobbits, but they're not-

  14. 1:03:18 – 1:35:24

    Naps, sleep debt, and safety: why you can’t ‘bank’ sleep, plus drowsy driving & school times

    1. JR

      You know, Wendy's at two o'clock in the morning or whatever. Um, what happens if you get naps? Like say if you only have five hours of sleep, but you take a two-hour nap during the day, does everything make up?

    2. MW

      Yes and no. So what you're talking about there is, uh, what we call prophylactic napping, (laughs) which is sort of strategically trying to help combat-

    3. JR

      Yeah.

    4. MW

      ... your deficiency of sleep. Naps can actually give you benefits. We've done some of these studies where they improve, you know, your learning, your memory, your alertness, your concentration, especially your emotional regulation too. Sleep is critical for emotional first aid and mental health. However, you can't keep using naps to self-medicate sort of short sleep of, you know, four or five hours each night. Um, we know that the system itself, your, your brain has no capacity to regain all of the sleep that it's lost. It will try to sleep back some of that debt. But what we've discovered, let's say I take you tonight, I deprive you of sleep, eight hours lost. Then I give you all of the recovery sleep that you want on a second, third, or fourth night. You will sleep longer, but you will only get back maybe just, uh, three or four hours of that lost total eight.

    5. JR

      Mm-hmm.

    6. MW

      So sleep is not like the bank. You can't accumulate a debt and then hope to pay it off at the weekend. And so there is no credit system within the brain for sleep. You can't bank it. Which is odd, by the way. I, I would love that system, you know?

    7. JR

      Yeah, then you would know what you owed.

    8. MW

      You would know what you owed. But I s- I could also just know when I'm going into a state of, you know, sleep debt and I could build up some credit.

    9. JR

      Ah.

    10. MW

      And there's precedent for this, by the way. There is a system like that in the brain, it's called the fat cell because there were times during our evolutionary past where we faced famine and we faced feast. And so the body learned to adapt to that and said, when you have feast, store it up as caloric energy in these things called adipose cells, fat cells. And then when you go into famine, you can spend that caloric credit. Where is that in the brain? Why don't we have that? The reason is very simple. Human beings are the only species that deliberately deprive themselves of sleep for no apparent reason. In other words-

    11. JR

      (laughs)

    12. MW

      ... Mother Nature has never faced the challenge of coming up with a safety net for lack of sleep. We've never been forced to come up with that solution. That's why we get such demonstrable disease, sickness, and impairment when you undergo a lack of sleep.

    13. JR

      So this is a recent occurrence in, in human beings, is that what you're saying?

    14. MW

      Yeah, I mean, the, the only time we see it in nature is when you go into s- conditions of starvation. The only way that you can get a species to sleep less, and it's very, very difficult to do because sleep is just so essential, is when you put them under conditions of extreme starvation. There they will forego some sleep to stay awake so that they forage in a larger sort of circumference area to try and find more food. It's probably the reason that when people go into fasting, their sleep is so terrible because the brain is receiving this ancient trigger that-... you're going without food, you're in a state of starvation. You need to stay awake and hunt for food. That's why your sleep gets so much worse when you're, when you're undergoing fasting.

    15. JR

      That's fascinating. I did not know that. So fasting is l- when you're talking about multiple-day fasting and not intermittent fasting?

    16. MW

      Um, th- we don't know the evidence for intermittent fasting. So, you know, if you're, some people are doing sort of 12 hours-

    17. JR

      Mm-hmm.

    18. MW

      ... 14 hours, 16 hours, ther- that doesn't seem to be extreme enough to trigger, uh, a change in sleep. But if you fast for these long periods, you know, two days, three days-

    19. JR

      Mm-hmm.

    20. MW

      ... four days, you can really see some quite marked sleep fragmentation. Sleep is de-... You know, ask any of those people, they'll tell you.

    21. JR

      That's fascinating because people always cite the health benefits of multiple-day fasts.

    22. MW

      Right.

    23. JR

      Do you think that that's just like a placebo effect?

    24. MW

      Um, I mean, certainly we know that there are chemical pathways that when you go into fasting are activated that seem to be beneficial for health outcomes. And there's a big literature on sort of fasting and aging with the mTOR pathway, for example. But, you know, w- we also know that as a species we, we were not designed to have such terrible fragmented sleep. And we spoke about how sleep regulates your appetite.

    25. JR

      Right.

    26. MW

      You know, the, if you're trying not to eat food and sort of control and manage your weight, the last thing that you probably want to do is be shortchanging yourself on sleep, because it's only going to make you even more hungry and reach for sort of worse food. So I still think there's room for fasting in the equation, but I think those extreme fasts, you know, and the havoc that it plays on sleep, it's still yet to be understood. You've got to be very careful with playing around with anything going beyond sensible, you know, behavior.

    27. JR

      So what does it? Like, what is, i- say if you're gonna fast for two days, what switches on that forces your, your body into this, uh, haphazard sleep program?

    28. MW

      So that's where that hormone ghrelin just kicks into high g- gear.

    29. JR

      Mm-hmm.

    30. MW

      That hormone that is just saying, "I..." It's a starvation hormone at that point.

Episode duration: 1:55:32

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