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April 25, 2018 - The Joe Rogan Experience
01:55:26
Joe Rogan Experience #1109 - Matthew Walker
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joe rogan
34:01
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matthew walker
01:20:24
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josh olin
00:02
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Speaker Time Text
unidentified
And we're live.
joe rogan
What's going on?
Did you sleep well last night?
matthew walker
I did.
I didn't sleep too badly.
I mean, hotels are a tough thing.
And we actually know the science that one half of your brain will actually not sleep as deeply than the other when you're sleeping in an unusual room, like a hotel room.
joe rogan
Really?
That's what fucks me up.
Because when I'm on the road, you know, I'll do three different hotels in a week.
Because I'll do like a Thursday, Friday, Saturday, like with gigs.
And then by the time Sunday rolls around, I'm a mess.
matthew walker
You're in rough shape.
unidentified
Yeah.
joe rogan
Is that what it is?
matthew walker
Yeah.
And it's a threat detection thing.
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.
joe rogan
That's how people at the DMV do it.
Those people that work at the Department of Motor Vehicles, they work half asleep.
You ever meet them?
matthew walker
I haven't, no.
joe rogan
Just teasing you.
It's your DMV listening, going, fuck you, man, next time you come in to get your license renewed.
matthew walker
There's my next NIH grant, I think, looking at the DMV in sleep.
joe rogan
TSA workers?
Same thing.
Same type of human.
matthew walker
That I've come across.
joe rogan
Yeah.
Them too.
I'm just kidding, fuckers.
Relax.
So when you're in a hotel room, what is happening that half your brain is not really sleeping?
matthew walker
Yeah, so there's different stages of sleep.
There are two principle types.
One is non-repid eye movement sleep or non-REM sleep.
The other is REM sleep, which is also known as dream sleep.
And non-repid eye movement sleep is further divided into four separate stages.
Which are unimaginatively called stages one through four.
We're a creative bunch.
joe rogan
Easy to remember.
matthew walker
It is true, 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, 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.
So it stays in this kind of lighter stage, almost like a threat detection system.
And you can imagine why.
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.
joe rogan
That makes so much sense.
And that really, for me, it fills in the blanks of why, even if I get seven, eight hours sleep on the road, I'm still kind of just out of it.
matthew walker
Yeah, and that's in fact probably one of the, I think, the most impressive parts of new research on sleep.
It's not just about quantity, it's also about quality.
And quality can be as detrimental, if you don't get it, as a reduction in total quality.
I mean, both are essential, but I think it speaks exactly to your point.
You just don't feel like it's a refreshing sort of deep sleep.
joe rogan
Yeah, it feels totally different.
It just feels like, I guess I would say, it feels like half asleep.
I mean, it's really kind of how it does feel.
One of the things that I noticed, I did this thing with my friends called Sober October, where we didn't smoke any pot or do no drinking at all, nothing, for a month.
And 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 is happening there?
matthew walker
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 have had, but have not been getting.
unidentified
Wow.
matthew walker
So that finally when the alcohol actually gets out of your system, sober October, love the name, 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 months.
joe rogan
Try 20 years.
matthew walker
I didn't want to make any assumptions.
So you get this REM sleep rebounded effect, and that's where you have these really intense dream sleep situations.
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 or Saturday.
They sleep in late.
They say, I just had these crazy dreams.
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 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.
joe rogan
Oh, wow.
So what is happening with marijuana, though, specifically?
Do you know?
matthew walker
Yeah.
So marijuana, it does help people.
Well, help.
It puts people to sleep quicker.
Although I think the question is whether it's really naturalistic sleep or not that they go into.
Certainly with alcohol, it's not.
That nightcap idea 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.
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 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.
joe rogan
Have there been any studies on chronic marijuana smokers, like those dawn-to-dust type characters that just are constantly high?
And what happens to their brain?
Because they must never hit REM sleep.
matthew walker
Yeah, so people haven't looked at marijuana.
They have looked at alcohol, though.
Exactly that.
So what happens is if you look at alcoholics...
They will have something often when they come off alcohol, something called delirium trems, which is where sort of DT. 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.
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.
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.
joe rogan
Wow!
I always thought the DTs were detoxing.
Someone said someone's going through the DTs.
So it's delirium tremor?
matthew walker
Yeah, delirium tremors.
joe rogan
So 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's physiologically happening?
matthew walker
So it's almost as though the veil of REM sleep gets pulled over the waking brain, as it were.
So you have this mixed state of consciousness that you can pick up with brainwave recordings.
And it just tells me, I mean, in some ways, how necessary sleep must be.
If that's the lengths that the brain will go to to get that which it's been missing, it just shows you why, you know, it took Mother Nature 3.6 million years to put this thing called an eight-hour sleep necessity in place.
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.
joe rogan
Wow!
Really?
matthew walker
Yeah.
joe rogan
And so many people take pride in that, too.
I don't need eight hours sleep.
I got three.
I'm good.
Ready to go.
Kick ass and dominate the world.
matthew walker
Yeah.
It's the sort of like sleep machismo sort of attitude.
joe rogan
There is a lot of that, right?
matthew walker
Yeah.
joe rogan
Not me, baby.
I like sleep.
matthew walker
Well, I mean, you'd be glad to know that then, you know, men who sleep five to six hours a night will have a level of testosterone, which is that of someone 10 years their senior.
So a lack of sleep will age you by a decade in terms of that critical aspect of wellness, virility, muscle strength, sexual performance.
unidentified
10 years?
joe rogan
That's incredible.
Wow.
We had a woman on the podcast, her name is Courtney DeWalter, and she's a ultra-marathon runner.
And she ran, she's a real freak.
I mean, like, an incredible athlete.
She ran this thing called the Moab 240. It's 238 miles through the Moab Mountains.
And she did it 22 miles faster than the second place man.
So she won it by like a whopping, I think it was 10 hours, 10 hours ahead of the second place winner.
And she slept one minute, one minute the entire time.
She tried to lie, this is over three days.
I think it took her less than three days.
I think it took her like two days.
She slept for one minute during the entire time.
She tried to lie down.
She said she laid down for a few minutes but she couldn't fall asleep.
And then she wound up actually just taking one minute and going to sleep.
And she said that one minute was like one of the most intense, restful minutes.
After that minute is over, she was woken up because she told her partner, her running partner, to wake her up at a minute.
And she's like, how long did you let me sleep?
And he was like, one minute.
She's like, wow, I feel great.
Let's go.
But she was saying that she hallucinates and that she starts seeing like rabbits are talking to her and she sees things that aren't there and like mystical beings and stuff.
She said it's really freaky, but she knows that she's hallucinating because she's done this.
She's done a bunch of ultra marathons.
So she just keeps going.
She just keeps going.
She's like saying hi to rabbits.
They're talking to her and stuff.
matthew walker
Yeah.
I mean, and you see these reports too.
I mean, there's a race, a cycling race, I think it's Bike Across America.
You've just got to go from East Coast to West Coast in as short a time as possible.
And that's exactly what they do too.
It's all about managing how little sleep that you get.
And they will explain these wild hallucinogenic experiences on the bike.
If you look at world records for people who have tried to sort of go without sleep, one of the most famous examples is a radio disc jockey called Peter Tripp back in the sort of 60s, 50s, 60s.
And he tried to break the world record.
He went eight days straight.
Yeah.
joe rogan
With no sleep?
matthew walker
Yeah.
He was broadcasting from Times Square.
He would do a show there.
And, you know, the scientist, the psychiatrist said, look, this is a very bad idea based on what we know.
Please don't do it.
And he said, I'm going to do it anyway.
And then the scientist being the good scientist, they said, great.
Do you mind if we study you?
Because it'd be a great paper to sort of, you know, to write up.
And they tracked him.
And by day three, he was having florid delusions and hallucinations.
He was seeing spiders in his shoes.
He became desperately paranoid.
He started to think that people were trying to poison him in his food.
At one point, it was the middle of winter.
Some guys came in with sort of these – it was New York wintertime – came in with these big jackets.
He thought it was the Secret Service coming to get him and he ran out into the road.
You know, these are strange things.
But so we know that that same profile of just starting to become, you know, psychotic, which is essentially what happens naturally when you dream that you are, I mean, all of us here, you know, as long as we slept last night, became flagrantly psychotic when we went into dream sleep.
Because you start to see things which are not there, so you hallucinate.
You believe things that couldn't possibly be true, so you're delusional.
You get confused about time, place and person, so you're suffering from disorientation.
You have wildly fluctuating emotions, something that psychiatrists call being sort of affectively labile.
And then how wonderful, we both woke up this morning and we forgot most if not all of that dream experience, so we're suffering from amnesia.
joe rogan
What is happening when you're having these hallucinogenic experiences?
Like, what are the chemicals that are causing it?
Do we know?
matthew walker
We do, yeah.
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 30% more active than when you're awake.
So, 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 part of the brain gets shut off.
So it's almost as though, you know, the prison guards are gone and everyone runs amok because there's no controller, you know, 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.
Because your frontal brain, the thing that makes us most human, you can say goodbye to that for the rest of dream sleep.
joe rogan
So there's no driver.
matthew walker
So there's no driver.
unidentified
Yeah.
joe rogan
Now, why do we forget?
Why do we forget those dreams?
Because I wake up and I am sure that I'm going to 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.
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 vary wildly from what is absolutely true.
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 and make themselves look better or make the situation look more dramatic.
But with dreams, that doesn't make any sense.
So 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, that was crazy!
What a dream!
And then I forget it 20 minutes later.
matthew walker
Right.
joe rogan
What is that?
matthew walker
So firstly, I mean, one theory of dreaming is that it's just simply a reconstruction when you wake up.
So you have these 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 don't believe that, though.
Your point is a really interesting one.
Do I remember my dreams?
That doesn't necessarily mean I forget my dreams.
And what I mean by that is accessibility versus availability.
So if you ever had that experience where you've woken up, you thought, I was definitely dreaming, I can't quite grab it, you know, and it's gone.
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.
Or someone says something to you, and you think, oh, that was the dream.
What that tells me as a brain scientist is that the memory is there, it's preserved, it's available.
But what happens most of the time when we wake up is that we lose the IP address to the memory.
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 sort of access that memory.
joe rogan
What's stunning to me is how quickly the dream evaporates, the memory of the dream, in relation to 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 you'd be able to tell your friends, like, yeah, some lady just randomly walked up to some guy and kicked him the balls.
Like, we would remember that.
And you would remember it ten minutes later.
You'd remember it an hour.
You'd remember it next day.
You'd be telling your friends, yeah, she just walked right up to him.
I remember it like it was yesterday.
Because it was.
Right?
matthew walker
Yeah.
joe rogan
But a dream.
It's going to be ten minutes ago, and you wake up and, dude, it was King Kong, and he was swinging from my ceiling, and somehow or another he fit in the room, but the room got bigger, and you have these crazy dreams, and then 20 minutes later you forget all of it.
Like, what is happening there?
matthew walker
So, one current explanation is that the chemistry of the brain when you go into dream sleep is radically different.
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 a stress chemical in the brain.
It's one of them.
That gets shut off during dream sleep, which is remarkable.
joe rogan
Even if you're panicking?
Like, what if you fall off a building?
matthew walker
Well, what's interesting is that that chemical is low whilst you're having that dream, but when you wake up from those, and some people often wake up, that's when you have the spike of noradhran, so it's still low when you're in dream sleep.
But there's another chemical that goes in the opposite direction.
It's called acetylcholine.
It's the chemical that is actually altered in Alzheimer's disease.
And these two chemicals will change essentially the input-output direction of information flow into the memory centers of the brain.
joe rogan
That makes sense because people take that as a nootropic.
matthew walker
They do.
joe rogan
Yeah, that's actually an alpha brain.
When you take that, it's been clinically proven to enhance memory, especially verbal memory and recollection of words and things like that.
matthew walker
That's right.
joe rogan
So that's happening while you're sleeping?
matthew walker
While you're in REM sleep, yeah.
But what may be happening, our current models, if you sort of build these neural models to sort of mimic dreaming, it may be that during dreaming, it's principally about the outflow of information to generate dreams.
And in fact, the chemical profile is oppositional to input, which is about saving.
So it's about sort of pumping out information rather than committing information.
And so when you come out of a dream sleep, you still get this sort of lingering after sort of taste of chemistry as it were in the brain.
That means that the dreaming brain is more programmed to be outputting a narrative and an experience rather than actually committing it to memory, which is the opposite direction if that makes sense.
joe rogan
It does make sense.
How aware are you of dimethyltryptamine?
matthew walker
I'm somewhat aware of it scientifically, not personally.
Experientially?
unidentified
Yeah.
joe rogan
Yeah.
One of the things about psychedelic experiences with dimethyltryptamine, first of all, it's endogenous.
Your brain produces it.
Your lungs, your liver produce it.
But when you have a DMT experience, after it's over, the memory fades very rapidly.
And it seems just like a dream in that regard.
While you're having it, what's bizarre is that you're having it while you're awake.
matthew walker
Yeah.
joe rogan
And then after you have it, within 10, 20 minutes, it is just like a dream that you can't remember.
I remember like little flashes of experiences that I've had.
And there's been a lot of speculation that that's one of the things that you're experiencing while you're in heavy REM sleep, and that could be responsible for the crazy visuals that you have that seem so vivid.
I mean, there's been times where I've had dreams where I was 100% convinced that I was awake.
matthew walker
Yeah.
joe rogan
And then something happened like I do this thing sometimes where I'll and if I do it consciously a lot I think I saw in one of those wacky movies like what the bleep do me know I think I saw it in that where you walk up to a door as you're walking through the door you knock on the side of the door and go am I awake?
Nope, not awake.
Or am I asleep, rather?
matthew walker
Yeah.
joe rogan
No, I'm not asleep.
Because I'm knocking on the door.
Well, I did that and my hand was just like going right through the wall.
And I went, oh, I'm fucking sleeping.
And then I woke up.
And I was like, whoa.
But the feeling that I had while I was in that dream, it was so vivid.
I mean, everything seems so real.
Like, what could possibly be causing me to construct this artificial reality in my mind that, at the moment at least, was indistinguishable from the reality that I experience right now?
And I'm assuming because I just knocked on this table that I'm awake.
matthew walker
Yeah, I really hope I'm not just a fictive character in your dreamscape.
joe rogan
Or maybe we're sharing a dream.
matthew walker
Yeah, very inception-like.
Is that possible?
Not based on the science so far.
But I think, you know, what you're speaking about there really is almost why would Mother Nature create this thing called the dream experience?
You know, what would be the function of Of essentially every night going into what sums up to be about two total hours of virtual reality experience and testing.
One possibility which is deeply unsatisfying is that it's just a byproduct.
It's just epiphenomenal.
That when your brain goes into this thing called REM sleep and all of the different patterns of brain activity that we described, an offshoot is this thing that we call dreaming.
In the same way that a lightbulb, the reason that we construct the apparatus that's a lightbulb is to produce light, but when you produce light in that way, you also produce heat.
It was never the function of the lightbulb, it's just what happens when you produce light in that way.
Maybe dreaming is just sort of the heat of REM sleep, and REM sleep serves lots of other functions, but that doesn't feel to me right though.
joe rogan
Why?
matthew walker
Well, firstly, I think it's probably additionally metabolically demanding to have dreams in addition to this thing called REM sleep.
And whenever Mother Nature burns calories, it's usually for a reason, because they're so precious.
joe rogan
That's a good point.
That makes sense, too.
Yeah.
I read some article about the lack of REM sleep with marijuana users, and it was trying to say, and it made me super skeptical even as a pot smoker, that it was trying to say that it's not bad for you because what it's essentially doing is bypassing the REM sleep and going directly into the deep sleep, and that it's helping you in that regard.
Does that make sense to you?
matthew walker
Doesn't make sense.
joe rogan
As a neuroscientist, he says nay, you fucking stoners.
matthew walker
I'm so deeply unpopular, you know, I'm telling people, you know, don't smoke pot, stay away from alcohol, you know, apart from a general personality, which is dislikable, this doesn't help me.
joe rogan
You're definitely not dislikable, but I don't think you're saying anything wrong.
I think...
I think marijuana, like most things, is best used in moderation.
And one thing that I got out of the Sober October thing wasn't just that it's fascinating to see the dreams just ramp up and get crazy, but also that when you take a few days off and then smoke a little pot, the pot actually has more of an impact.
In fact, one of my favorite psychedelic authors and lecturers, the late, great Terence McKenna, his advice was to not do marijuana for long periods of time and then do as much as you could stand.
And he was a real psychedelic adventurer.
And his thought was to really get the benefit out of marijuana, it's not something that should be used daily and recreationally.
It should be used as a psychedelic sacrament.
Not should be, because he actually did smoke pot pretty regularly.
But his thought was if you really want to get the full impact of it, you shouldn't be accustomed to it.
And when you're accustomed to it, you build up a tolerance to it and it doesn't have the same impact.
It's that thing, I don't know if you've ever been around pot smokers, but when someone doesn't smoke pot and then they get talked into smoking pot with some pot smokers, it's always a terrible idea.
Because you've got a bunch of people with super high tolerances and some poor person that doesn't have any tolerance and they just get taken down a tornado rabbit hole journey into their childhood.
matthew walker
It's like 0 to 60 in like 1.2 seconds.
joe rogan
They're just so paranoid and thinking about everything and freaking out and all these sensations that they've just never experienced before.
But the idea that you could bypass REM sleep and go straight into the deep sleep, that doesn't make any sense to you?
matthew walker
No, it doesn't.
And what we've learned over the past 30 or 40 years is all stages of sleep are important.
When you think about sleep as a state, it makes no sense.
Firstly, you're vulnerable to predation.
You're not finding food.
You're not finding a mate.
You're not reproducing.
You're not caring for your young.
On any one of those grounds, sleep should be strongly selected against.
As a collective, I mean, it's almost idiotic.
If sleep does not serve an absolutely vital function, it is the biggest mistake that the evolutionary process ever made.
And that counts for all of the stages of sleep, too.
Again, Mother Nature wouldn't waste time putting you into a state that wasn't necessary.
And what we've discovered is that all of those different stages of sleep that we spoke about all have unique and separate functions.
So you can't shortchange any one of them.
You don't need to bias towards one and try and placate the other.
You know, evolution has taken a long time to get the blueprint accurately correct for each physiological individual.
I wouldn't play around with it and think that you're smarter than that process.
joe rogan
Right.
When I read it, I felt like it was a justification for smoking a lot of pot.
Like, man, you're just getting deeper sleep, man.
You don't need that REM sleep.
You're passing it up, man.
You just go right into the deep, heavy, necessary sleep.
matthew walker
Au contraire.
joe rogan
Au contraire, potheads.
So, what is happening to the body during REM sleep that's so critical, that one particular aspect of sleep?
matthew walker
So, firstly, in the body, your cardiovascular system seems to do something quite strange.
It goes through periods of dramatic acceleration and then dramatic deceleration.
joe rogan
During REM sleep?
matthew walker
Yeah, during REM sleep.
It's quite unpredictable, too.
We also know that during REM sleep, your brain paralyzes your body so that your mind can dream safely.
So, I mean, and that makes a lot of 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.
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 incarceration.
joe rogan
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'd be sleeping and I would move and throw a kick in the middle of the night.
And I remember 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.
matthew walker
Do you actually remember?
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?
joe rogan
I believe I had a recollection.
It's been a long time, but I believe I had a recollection.
Like, I would be, like, in bed with my girlfriend.
I'd wake her up, too.
You know, because I'd just jolt.
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 attribute it to the idea that it's so extreme, like, the activity of fighting is so extreme that my...
Brain had kind of like hypercharged itself to compete at this very high level, you know, and that this was like so unusual that it was it was almost that red alert all the time and maybe even trying to work out patterns while I was sleeping.
matthew walker
That's exactly the evidence that we have now.
So for things like motor skills or even rats running around a maze where they will learn specific sort of navigational pathways and even skilled motor movements, what you can do is you can place these electrodes into centers of the brain.
My sleep center works on humans, but other people have done these 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 you can listen to the brain cells learning the signature of that maze.
So it goes...
What was amazing is that when you let those rats sleep, but you keep listening to the brain, what you hear is 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.
It's replaying, but at a speed that is 20 times faster.
So, you know, now we start to get into this Inception world, and I don't mean to because the scientific data, 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 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 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 percent better in terms of your skilled performance than where you were at the end of your practice session the day before.
joe rogan
Wow!
Wow!
matthew walker
I mean, sleep is the greatest legal performance enhancing drug that most people are probably neglecting in sport.
joe rogan
Wow.
And not just for your physical performance, but actually skill learning.
matthew walker
That's right.
Skill learning, memory, and then also, you know, downstairs in the body, all of the recuperative benefits.
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 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 going to be physically exhausted by round 7 rather than round 10. Wow.
joe rogan
But, well, that's a really hard thing for fighters because they have a very difficult time sleeping the night before a big fight.
matthew walker
Yeah.
joe rogan
It's very, very difficult because there's anxiety.
And I would imagine it's got to be I mean, it's probably going to take a huge toll.
I mean, it's probably 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.
matthew walker
I mean, it's I think, you know, it's one of what constantly trying to hack the physiological system, especially in elite sports these days, because, you know, small fractions of a percent of gain can make a huge difference.
joe rogan
That sounds like 30%.
That's a monster.
matthew walker
Sleep is huge, yeah.
I mean, your time to...
It's not just physical exhaustion, but 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.
joe rogan
Man, that makes so much sense.
Because when I was doing...
I was doing Fear Factor, and I was doing stand-up comedy, and then I was also doing another television show, and I was doing jujitsu.
I never got eight-hour sleep.
I mostly got four.
Usually got four.
And my cardio always sucked.
matthew walker
Yeah.
joe rogan
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.
matthew walker
Yeah, it's a huge part of that equation.
unidentified
Wow.
joe rogan
Now, how many hours of sleep should you get?
matthew walker
Somewhere between, excuse me, somewhere between seven to nine hours.
Once you get below seven hours of sleep, we can measure objective impairments in your brain and your body.
joe rogan
I can show that in the last two days.
And I can show it because I basically did the same workout two days in a row.
The day before, I had flown back from Boston, very tired.
Hanging out with my kids all day.
Went to get some sleep, but then I had to do some stuff at like 2 o'clock in the morning.
And I just never really got good sleep.
And then my youngest daughter got up at 5. She was crying.
And then eventually my alarm went off at 8. So my sleep was like 3 or 4 hours.
It was all screwy.
And the night before it was even less because 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.
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, ugh.
Well, last night, last night I slept seven and a half hours.
Woke up today, lifted weights, ran, 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 lifted weights today as well, and I just feel great.
So I could see it physiologically in the difference in my performance in 24 hours.
matthew walker
Yeah, and that's noticeable.
I mean, we see that too.
You know, 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 there 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 are 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.
joe rogan
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 turn a knee?
matthew walker
Yeah, it's all of those things.
I mean, even if you look at microbalance, if you look at sort of these stability muscles versus, you know, major muscles, those stability muscles also fail when you're not getting sufficient sleep.
And I think we often underestimate how critical they are in sport performance, particularly in terms of combating and placating injury risk, too.
So if you just get someone on a stability ball...
You know, sort of just dose them down with sleep, eight hours, five hours, you know, three hours.
And just notice how those stability muscles help you balance, just the basic act of balance.
That deteriorates dramatically.
No wonder you're getting more injury risk.
joe rogan
Totally makes sense.
Now, as a neuroscientist, what do you attribute, when people talk about visualization, and visualization is a huge factor in improving technical skills, specifically martial arts, which is a Big fan of, obviously.
Martial arts, when you visualize, people who visualize, who sit down and go over their body, going through the motions and doing things, those people perform better.
They perform better.
They learn quicker.
What do you attribute that to?
Do you think it's the same thing as what's happening when you're sleeping, just maybe to a lesser extent?
matthew walker
I think it's to a lesser extent.
But people have done those studies where they've looked at sort of whether you actually physically practice, let's say, on a keyboard, just because it's easier to sort of manage in a laboratory, versus just imagining sort of typing out that sequence and, And just the act of physical visualization of sort of imagination of that motor skill.
It's about 50% as effective as physically performing it too.
And it's 50% as effective, what I mean there is, in changing the plastic connections within the brain.
So even just visualization, you know, passive play, as it were, still can actually cause a rewiring of the brain beneficially.
joe rogan
Wow.
You know, learning techniques, specifically martial arts techniques, my good friend Eddie Bravo is a world-famous jiu-jitsu instructor.
He's always...
Comparing it to tying your shoe.
And he said, do you know how like when you were a little kid and you're trying to figure out how to tie your shoe, it's an extremely difficult thing to do.
You're like, how do I do this?
And you put that down and you do loops.
I'm watching my seven-year-old daughter go through that right now.
But now, as a grown man, when I tie my shoe, I could just be talking to you.
What?
Oh yeah, we're going to go tomorrow.
And I'll be doing it.
I don't even know what I did.
If you tried to ask me to explain how I tie my shoe, I'd be like...
How do I tell my shit?
I don't even know how I do it because I have it in there.
And the idea with martial arts is you've got to be, all of your techniques have to be automatic.
Someone extends the arm, you instantly hook it and go into the arm bar.
You have to have these paths so drilled in that you don't even know you're doing them until it's over.
matthew walker
Yeah.
So automaticity is one of the things that sleep actually accomplishes.
You know, I was talking about those 20 to 30% benefits in motor skill performance.
So we did some additional studies to actually say, well, how does sleep do that?
You know, where in your skill performance does sleep give you the benefit?
So you're right, tying a shoelace, you know, even driving a car with stick, you know, at first it's just overwhelming.
It's so difficult.
It's clutch, it's gas pedal, you know, it's gear.
And now it's just second nature.
You know, it's shifted from conscious to automatic, from conscious to non-conscious.
If you look at performance that is conscious and not automatic, it's usually very staccato.
It's this, then it's that, then it's that.
It's not fluid.
If you heard someone trying to sort of play piano to begin with, it doesn't sound very fluid.
You know, as someone who is a maestro, it just flows out of them.
So we looked at this with motor skill performance, again, sort of like keyboard playing musicianship.
And you learn and you learn and you get better.
And let's say that you type a sequence, let's say 4-1-3-2-4, and people learn it, but they have these problem points throughout the sequence.
They go 4-1-3-2-4, 4-1-3-2-4, as if it's a sticking point.
It's the same thing with any skilled performance in athletics.
And it's the brain chunking things up.
A very long motor sequence gets chunked up into small sort of digestible bites.
It's a good way to begin learning, but it's not a way to create automaticity.
At some point, what you have to do is stitch all of those things together, and it just flows.
joe rogan
Like a sentence?
matthew walker
Like a sentence, yeah.
Like a piano piece.
Like, you know, a sequence of movements.
If you've got, you know, in martial arts, you've got, you know.
So...
What we found was that before sleep, you've got these big problem points, these gaps in your motor skill learning.
Sleep does not necessarily improve the places where you're already good.
Sleep is intelligent.
It goes in, finds that problem point, that friction point in your motor skill sort of deficit, and it smooths it out.
So you come back the next day and now it's just 4-1-3-2-4, 4-1-3-2-4, 4-1-3.
It's automaticity, and it's exactly what you're describing.
You know, speak to musicians, they'll say, I was playing, I just couldn't get that piece the night before, and then I came back the next day and I sat down and I could just play.
Sleep's doing its work.
joe rogan
I've heard that too with problems, and that's why people say sleep on it.
matthew walker
Yeah.
Yeah, you've never been told to stay awake on a problem.
joe rogan
Yeah, it's true, right?
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 like, eh, it's all right.
matthew walker
Yeah.
joe rogan
It's going to be fun.
matthew walker
Yeah.
joe rogan
I got it.
I know what to do.
matthew walker
And there's lots of anecdotal evidence of sleep-inspired creativity.
And now this 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 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 incredible solutions to previously impenetrable problems.
And lots of anecdotes, you know, Dmitry Mendeleev came up with a 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.
Einstein, by the way, 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 workbench.
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 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 ball bearings in his hand 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.
Isn't that brilliant?
No wonder you're never told to stay awake on a problem.
And in every language that I've inquired about today, 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, I think it's important that the French, the French translation is much closer to 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 British and the French, you know?
joe rogan
Yeah, the French trying to fuck everything, trying to fuck their problems.
unidentified
I'll lose my British passport for saying that, but that's okay.
matthew walker
He won't.
joe rogan
I will.
But I won't either.
It's just a joke.
That's fascinating that Einstein figured that out too, that he literally had like a whole routine and that he would drop this ball and hit it, bang, and wake up and start writing.
Self-medicating.
I would love to be in the room watching Einstein do that.
It must have been fascinating.
matthew walker
Oh, sorry.
I said Einstein.
It's Edison.
My goodness.
I'm an idiot.
Edison.
unidentified
Oh, okay.
joe rogan
That changes everything.
Wasn't Edison a thief, though?
Didn't he steal everything from Tesla?
matthew walker
There's argument to be made.
He has a lot to answer for, by the way, in terms of the way that we're sleeping.
He was the first person to electrify society.
Not necessarily create the light bulb, but he really shifted us from a point where now we controlled the night in terms of illumination.
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.
joe rogan
Yeah, not just that, but also our inability to see the stars anymore, the light pollution that we have at night.
I think it's a giant shift in perspective.
Have you ever been to a planetarium or an observatory, like one of those at night?
There's a Keck Observatory in Hawaii.
It's a place I try to go to every year.
Really stunning, because it's very high up.
I think the observatory is 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 the visitor center, and you go to the visitor center, and they have some telescopes set up.
But 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!
And 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 the 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 used diffused lighting all over the island 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 because everything's lit up.
It's crazy bright.
I think that perspective, that's 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 got to be a big factor in why people sleep so little, right?
matthew walker
We know it is now.
I mean, these studies have been done.
The first part is the external light, which is street lighting.
Even if you've got curtains, that can still bleed through.
But then, when you come into the home, the invasion of light into the home by way of technology has been a big problem.
joe rogan
People looking at their phones before they go to bed?
matthew walker
Well, firstly, yeah.
I mean, the incandescent light bulb sort of was the start of it.
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.
And they've done studies where, for example, one hour of iPad reading versus just one hour of reading on a book 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 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.
unidentified
Wow.
matthew walker
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.
joe rogan
Wow.
What should someone do if they have a hard time sleeping?
Like, say, if you're a person who has insomnia, you have a hard time getting to bed, you have a hard time staying asleep.
When you wake up, you can't go back to bed.
Are there strategies?
matthew walker
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, 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.
You'd 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.
It 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.
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.
joe rogan
I've seen people use cold pads.
Have you seen those?
You sleep on these cold pads?
What do you think of those?
matthew walker
Yeah, I mean, the evidence is pretty good that cooling the body actually works.
In the book, I write about 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.
So, and you can even look at studies where people sleep semi-naked and And that also seems to improve their sleep and they get a little bit more deep sleep too.
So cold is better.
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.
unidentified
Really?
joe rogan
So you should go to sleep with socks and gloves on?
matthew walker
Yeah.
Or better still have a hot bath.
Evidence here too that I discuss where people say, you know, I get out of a hot bath, I feel nice and toasty, I'm relaxed and that's why I fall asleep.
It's the opposite.
When you get into a bath, you get vasodilation.
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.
joe rogan
Wow!
So your core body temperature plummets and that's what makes you sleep easier.
matthew walker
Yeah.
joe rogan
That sounds so counterintuitive, but it makes sense.
matthew walker
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.
Temperature is at its lowest in the nadir of the night, you know, three or four 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.
If you look at those tribes, by the way, and when they go to sleep and they wake up, You know, they go to sleep probably at two hours after dusk, sort of eight to nine in the evening, wake up about half an hour, even an hour before dawn.
It's the rise in temperature rather than light that triggers their awakening.
But there's a reason, you know, have you ever thought about what the term midnight actually means?
middle of the night.
unidentified
Right.
matthew walker
And that's what it should be for all of us.
But in modernity, we've been dislocated from our natural rhythms.
And now midnight has become the time when we think I should check Facebook last time.
You know, I should send my last email.
unidentified
Yeah.
matthew walker
That wasn't that is not how we were 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.
joe rogan
Yeah, I've heard this recently, that people, that you should have two sleeps.
The idea of two sleeps.
matthew walker
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, 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 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, just means after lunch.
And if I measure your brainwave activity with electrodes, I can see a drop in your physiological alertness somewhere between 2 to 4 p.m.
in the afternoon.
joe rogan
But is that dependent on diet?
matthew walker
It's not.
People think it is, you know, especially after they've had a heavy lunch.
joe rogan
Yeah.
matthew walker
You can actually just have people fast instead of, well...
Fasting for long periods of time actually makes your sleep much worse.
But 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.
joe rogan
But is that dependent upon their standard diet?
Because if someone is on a carbohydrate-rich diet, a lot of times you do get that spike and then you crash.
Yeah.
But when people are on low-carb and high-fat diets, they don't get that, and they tend to be more even with their energy through the day?
matthew walker
Yeah.
So yeah, that sort of more constant release of energy can actually help you sort of almost combat that lull.
joe rogan
But that lull exists no matter what.
matthew walker
Exactly.
joe rogan
So even if you don't think it exists, it's there.
matthew walker
It's still present.
joe rogan
Interesting.
So why did they do that in the Dickens era?
Is there a root cause of their double sleep thing?
matthew walker
We don't know.
I mean, it's hard to sort of really go back.
joe rogan
Fascinating.
matthew walker
Yeah, it's incredible.
joe rogan
That was a trend.
matthew walker
Yeah, that it was a movement.
joe rogan
That they would just wake up and do things and...
matthew walker
Yeah.
joe rogan
Maybe it's because they didn't have TV. They didn't know what to do with themselves.
matthew walker
Yeah.
Sounds like they did some pretty interesting things, which were nice.
Yeah.
joe rogan
Well, they created a lot of art then, too, right?
A lot of writing and a lot of fascinating stuff came out of that time.
Now, when you're measuring people's health and when you're measuring people's health in regard to how much sleep they have, How do you do that?
Do you just talk to people?
Do you do surveys?
How do you get a detailed analysis of people's patterns?
matthew walker
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.
unidentified
Whoa.
matthew walker
Short sleep predicts all cause mortality.
joe rogan
Which is really ironic because people that want to sleep less are like, you know, I don't have a whole lot of time.
You know, this life is short.
josh olin
It's fucking shorter if you sleep less.
matthew walker
Yeah, that old maxim, you know, you can sleep when you're dead.
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.
joe rogan
Yeah, that's counterintuitive to people.
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'd make best use of time by being awake less.
matthew walker
Exactly.
joe rogan
Which is crazy.
matthew walker
I mean, wakefulness, firstly, from a brain perspective, is low-level brain damage.
We know that.
joe rogan
Wakefulness is?
Like right now, you and I are getting low-level brain damage.
matthew walker
Yeah, that's right.
And it's sleep that offers a reparatory function.
And 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.
joe rogan
What studies, if any, have been done on people that work the third shift?
matthew walker
So people have looked at shift work in general.
They haven't necessarily split it down to that granular point.
But 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 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.
joe rogan
Whoa!
matthew walker
Yeah, so jobs that may induce cancer because of a disruption of your sleep-wake rhythms.
joe rogan
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?
matthew walker
They do.
Both of those things.
joe rogan
Yeah.
matthew walker
And we know exactly the pathways.
So there are two hormones that control your appetite and your weight.
One is called leptin, the other is called ghrelin.
They sound like hobbits, but they're not the real hormone, the real chemicals.
unidentified
They do sound like hobbits.
matthew walker
It's bizarre.
So leptin is the chemical that tells your brain you're full, you're satiated, you don't want to eat anymore.
Ghrelin does the opposite.
It's the hunger hormone.
It says you want to eat more, you're not satisfied with your food.
If I take people, and these studies have been done, we've done some of these studies too, and you just put a group of healthy people on four or five hours of sleep for, let's say, one week.
And you look at those two hormones, they go in unfortunately opposite directions.
So leptin that says you're full, stop eating, that gets suppressed by a lack of sleep.
Ghrelin, the hunger hormone, that gets ramped up.
So firstly, people who are sleeping just five to six hours a night will on average eat somewhere between 200 to 300 extra calories each day because of their underslept state.
Add that up, it's about 70,000 extra calories a year.
It's about 10 to 15 pounds of obese mass each year, which for me is starting to sound familiar.
But what we also know is that it's not just that when you're underslept, you eat more.
You eat more of the wrong things.
And the great scientific work, if you give people this sort of finger buffet and they can eat whatever they want and it contains all of the different food groups, And you sleep deprive them or you give them a full eight hours of sleep.
Yes, they start to overeat by somewhere around about 450 calories with total sleep deprivation.
But what they go after is heavy hitting carbohydrates and simple sugars process food.
And they stay away from the healthy sort of leafy greens, nuts, proteins, etc.
So you're not just eating more, you're eating more of the wrong things.
And that's why a lack of sleep has such a strong obesogenic profile to it.
And you can take a step back, too, and you say, well, if you look at the rise of obesity over the past 70 years, just this upward exponential increase, and if you plot on the same graph the amount of sleep that society is getting, it goes in the opposite direction.
As sleep time has declined, obesity rates have increased.
I'm not going to sit here and tell you that the obesity epidemic is simply a sleep problem.
It's not.
It's a problem of us being sedentary, processed foods, larger food serving sizes.
If you take those factors, though, by themselves, they cannot explain the increase in obesity.
Other things are at play.
Is sleep one of them?
Now we know it is.
It's a critical factor in the obesogenic epidemic.
joe rogan
I know from personal experience when I'm tired, I always gravitate towards the worst choices.
For me, it's late night cheeseburgers.
matthew walker
Yeah.
joe rogan
You know, Wendy's at two o'clock in the morning or whatever.
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?
matthew walker
Yes and no.
So what you're talking about there is what we call prophylactic napping, which is sort of strategically trying to help combat 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.
We know that the system itself, 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 three or four hours of that lost total eight.
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 would love that system.
joe rogan
Yeah, then you would know what you owed.
matthew walker
You would know what you owed.
But I could also just know when I'm going into a state of, you know, sleep debt, and I could build up some credit.
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, 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.
joe rogan
So this is a recent occurrence in human beings?
Is that what you're saying?
matthew walker
Yeah.
I mean, the only time we see it in nature is when you go into 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 undergoing fasting.
joe rogan
That's fascinating.
I did not know that.
So fasting is when you're talking about multiple day fasting and not intermittent fasting?
matthew walker
We don't know the evidence for intermittent fasting.
So, you know, if you're some people are doing sort of 12 hours, 14 hours, 16 hours.
That doesn't seem to be extreme enough to trigger a change in sleep.
But if you fast for these long periods, you know, two days, three days, four days, you can really see some quite marked sleep fragmentation.
You know, ask any of those people, they'll tell you.
joe rogan
That's fascinating because people always cite the health benefits of multiple day fasts.
Do you think that that's just like a placebo effect?
matthew walker
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.
There's a big literature on sort of fasting and aging with the mTOR pathway for example.
But, you know, we also know that as a species, we were not designed to have such terrible fragmented sleep.
And we spoke about how sleep regulates your appetite.
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.
joe rogan
So what does it, like what is, say if you're going to fast for two days, what switches on that forces your body into this haphazard sleep program?
matthew walker
So that's where that hormone ghrelin just kicks into high gear.
That hormone that is just saying, it's a starvation hormone at that point.
It's not just a hunger hormone.
You've gone over into starvation.
And that will promote alertness.
It promotes chemicals that try to keep you awake.
Chemicals like dopamine to sort of force you wide awake.
joe rogan
So it's forcing you to go hunt or gather.
matthew walker
That's right.
joe rogan
And this is even if your body goes into a state of ketosis?
matthew walker
That we don't know.
People have not tried to correlate sort of, you know, the profile change in ketosis versus alterations in sleep.
I actually think it would be fascinating.
You know, maybe there's a peak where it's bad and then you sort of you crest it and then things get better.
You know, does the body acclimate to that?
I don't know.
We've never seen the body being able to sort of re-engage with, you know, cognitive function with a dose of sleep deprivation that keeps going.
So if I, and these studies have been done, take people and give them two weeks of seven hours of sleep, five hours of sleep, three hours of sleep, or no sleep.
You know, even by sort of seven days or even 14 days of six hours of sleep, your cognitive performance just nosedives like a dart into the ground.
And it doesn't show any signs of leveling off as if there is no asymptote that it could keep going.
And by the way, people should know that after 20 hours of being awake, you are as impaired cognitively as you would be if you were legally drunk.
joe rogan
Wow, what about physical movement?
matthew walker
Same thing.
Yeah, in terms of your alertness and reaction time.
But it's worse, and this is where, you know, drowsy driving comes in.
For every 30 seconds that we've been speaking, there has been a car accident linked to sleeplessness.
Drowsy driving, it seems, kills more people on the roads than either alcohol or drugs combined.
Why are drowsy driving accidents so deathly?
Now, I'm not endorsing those other things, of course not, but let's just think about why that's the case.
When you're underslept, you start to have what are called microsleeps.
Sometimes your eyelid does not close all the way, it just partially closes, but the brain essentially goes to sleep for just a very brief period of time.
And you can even see individual brain cells, looks like they go to sleep during these microsleeps.
At that moment, if you're traveling in a vehicle on the freeway, you've got a one-ton missile traveling at 65 miles an hour, and no one is in control.
joe rogan
One ton if you're lucky.
matthew walker
Yeah, yeah, exactly.
joe rogan
When was the last time you saw a 2,000-pound car, unless you have a Miata?
matthew walker
Yeah, yeah, or a McLaren P1. But, you know, if you are...
joe rogan
Even those are heavier than that.
matthew walker
Are they really?
joe rogan
Yeah.
matthew walker
Shows my lack of knowledge, despite living them.
But...
You know, I think what happens here is that when with drugs and alcohol, it's often the case of a problem of later reaction.
With a lack of sleep, it's a problem of no reaction at all.
joe rogan
So you're out of it.
matthew walker
So you're out of it.
So rather than breaking too late...
There's just no braking whatsoever.
joe rogan
Yeah, I have a tip for people, too.
If you find yourself tired and driving and you have to stay awake, take either ice or ice-cold water and put it in a washcloth.
And then rub your face with it.
It keeps you awake.
matthew walker
Works.
joe rogan
Yeah, it works.
I mean, if you're forced to drive for whatever reason, you have 20 minutes to go and you're really exhausted, do that.
Ice is the best.
Take a wet cloth, put ice inside of it, and just rub your face.
It just wakes you right up for whatever reason.
matthew walker
I mean, the statistics around drowsy driving are frightening.
joe rogan
It's a weird thing when you're on the road.
There's something about those white lines that just want to put you to sleep.
There's no other time where I feel more compelled to just conk out while I'm awake.
matthew walker
It's probably one of the greatest sedatives known to man.
It's that monotonous behavior.
And the longer you go with that monotony, the worse things get.
And if you look at teenagers, that's where we see some of the greatest impact of drowsy driving.
It's the leading cause of death in most First World nations.
Suicide is second.
joe rogan
Wow, that is crazy.
matthew walker
And it speaks to this model of later school start times.
They've done these studies.
There was a great one that was done, I think, in Teton County in Wyoming.
They shifted their school start times from 7.35 in the morning to 8.55 in the morning, much more biologically reasonable for teenagers.
The only thing more impressive than the extra hour of sleep that those teenagers reported getting was the drop in vehicle accidents.
There was a 70% reduction in car crashes the following year when they made that time to 7-0.
joe rogan
Holy shit.
matthew walker
So the advent of ABS technology, for example, anti-lock brake systems, that dropped accident rates by 20 to 25%.
Some deemed it to be a revolution.
Here's a simple biological factor, sleep, that will drop accident rates by 70%.
unidentified
Wow.
matthew walker
So I think if our goal as educators truly is to educate, and we've spoken about learning and memory, 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.
joe rogan
Why do we do that?
And not just early school times, but early work times too.
I was driving to the airport the other day at 6am.
6am, bumper to bumper traffic on the 405. I was like, this is insane.
Look at these poor fucks.
matthew walker
What are we doing?
And if you're in the car at 6am there, it means that you probably woke up.
Average school start times in the US, some of them 7, 7.25.
Buses for a school start time of 7.25 will begin leaving at 5.30 in the morning.
That means that some kids are having to wake up at 5.15, 5 o'clock, maybe even earlier.
It's just lunacy.
joe rogan
It is lunacy.
Now, why do they do that?
I mean, it's just a pattern that they've always done, and they never corrected it?
matthew walker
Yeah, it's a pattern that actually has changed over the past 30 or 40 years.
I mean, American schools used to start around 9 o'clock, and it started to shift ever and ever earlier.
Why?
unidentified
Why?
matthew walker
Part of it is because of work times that parents had to get to work at ever earlier start times.
joe rogan
So they dropped the kids off before work.
matthew walker
Yeah.
And then bus unions and bus schools, they comply to that same timeframe as well.
And it becomes very difficult.
I don't mean to chastise school systems or the bus unions.
It's an incredibly difficult logistics problem.
But I have to think that, you know, what is our goal here?
If our goal is to keep our kids safe and to get them well-educated and get information into the brain and nurture them and, you know, create them to be the next generation, early school start times, you know, are not the thing to do.
joe rogan
There's a lot of lazy kids out there that are going, yes!
Preach on, doctor!
Preach!
matthew walker
I mean, the data, you know, they looked at these academic things, too.
You know, one of these, another example comes from Adena in Minnesota, and they shifted school start times from, I think it was 7.25 to 8.30 in the morning, and they looked at SAT scores.
And in the year before they made the time change, the top 10% performing students got an average SAT score of 1,288, which is a great score.
The following year, when they were going to school now at 830 rather than 725, the average SAT score was 1,500.
That's a 212-point increase, which is non-trivial.
joe rogan
Wow.
That's gigantic.
matthew walker
Yeah.
joe rogan
Yeah, I think it's the school time in correlation with the work time.
It's very difficult to get people off of that.
matthew walker
Yeah, and that's part of what modernity has done.
We're working longer hours and also we're commuting for longer durations of time.
So therefore people are having to wake up earlier, they come home later, and the one thing that gets squeezed, sort of like vice grips, is this thing called sleep.
And the decimation of sleep throughout industrialized nations as a consequence is having a catastrophic impact on our health and our wellness and the safety and the education of our children.
Silent sleep loss epidemic.
joe rogan
Wow.
Now, other than making the room cold and warming up your hands and your feet and things along those lines, what about diet or even time that you eat?
Is there a specific time before you go to bed that you should eat?
How much time should you give yourself to digest your food?
matthew walker
So the general advice right now is don't go to bed too full and don't go to bed too hungry.
Again, if you're going to bed too hungry, you can get that sort of that signal of I'm starting to go into low level sort of starvation and that can keep people awake at night.
The evidence in terms of diet composition and sleep is quite unclear.
It's not a particularly well-researched area right now.
What we do know is that diets that are high in sugar and sort of heavier stodgy carbohydrates and low in fiber, those diets tend not to be good for sleep.
You tend to have less deep sleep and your sleep is also more fragmented throughout the night.
So that's sort of right now the best advice.
joe rogan
So you should eat several hours before you go to bed, but not five hours.
matthew walker
That's right, yeah.
joe rogan
Like two hours, maybe.
matthew walker
And it's different for different people, and you will know it, you know, if you're sort of starting to wake up with really severe hunger pangs.
joe rogan
What about supplements, like melatonin supplements or things along those lines?
matthew walker
Melatonin is efficacious.
It's useful when you're traveling between time zones.
So at that point, your body clock, your internal clock is out of sync with the actual real time in the new time zone.
And let's say I fly from Los Angeles over to London back home.
You know, my melatonin spike is going to be eight hours in the past, you know, sort of back in time.
It's not going to arrive with me for eight hours.
So I can take some melatonin and I can fool my brain into thinking, oh my goodness, it's actually dark.
When despite in California it's still daylight once I've arrived at Heathrow Airport.
So you can use melatonin strategically for jet lag.
Once people however are stable in a new time zone, melatonin does not seem to be efficacious for helping sleep.
That said, though, if people out there are taking melatonin and they think it helps, I would tell them to keep taking it because the placebo effect is the most reliable effect in all of pharmacology.
So if it works for you, no harm, no foul.
Keep taking it.
joe rogan
Interesting.
So the people that take melatonin nightly...
Like, this is what gets me to go to bed.
Really, they're just playing a trick on their mind.
matthew walker
Yeah, unless you're an older individual where your sort of 24-hour rhythm, it's called your circadian rhythm, starts to get blunted and it's not as strong anymore, that's where nightly use of melatonin actually has been demonstrated to be efficacious.
But if you're young, healthy, and you're taking melatonin, it's unlikely that it's actually helping your sleep.
That's probably the placebo.
joe rogan
So it really should just be just for traveling.
matthew walker
Yeah.
joe rogan
Or weird situations where your sleep is interrupted.
matthew walker
That's right.
joe rogan
And you need to kick it into gear.
matthew walker
Bring it back online, yeah.
joe rogan
So it's almost like a hack.
matthew walker
Yeah, it's definitely, you know, that's one way that you can hack jet lag.
I mean, there's no cure for jet lag, but there's actually lots of ways that you can hack jet lag.
joe rogan
Are there any other vitamins or nutrients or particular foods that enhance the sleepy effect?
I mean, there's always the thing about tryptophan.
Everybody thought that tryptophan was in Turkey.
matthew walker
Yeah.
joe rogan
But what I read was that was bullshit.
And what was really going on was that you just ate a gigantic meal and it's filled with stuffing and mashed potatoes and all those carbohydrates cause you to just crash.
matthew walker
And it's usually, it's the time that everyone goes back through into sort of the living room.
You lie down.
Most people are chronically sleep deprived.
And finally you get the opportunity to sort of just rest and no one's doing anything because there's no plans.
joe rogan
What do you think the numbers are of sleep deprived people in this country?
matthew walker
So we know those numbers, actually.
Almost one out of every two adults in America are not getting the recommended eight hours of sleep.
Almost one out of every three people that you pass on the street are trying to survive on six hours or less of sleep.
Back in 1942, Gallup did a poll, and what they found was that the average American adult was sleeping 7.9 hours of sleep a night.
Now that number, most recently, is down to 6 hours and 31 minutes for the average adult during the week in America.
That's the average, by the way.
That means that there's a huge swath of people well below that average.
joe rogan
And what about the people that say that they sleep, they go to bed, they sleep five hours, they wake up and they feel great?
matthew walker
Yeah.
joe rogan
Is that bullshit?
matthew walker
We have the number of people who can survive on six hours of sleep or less without showing any impairment rounded to a whole number and expressed as a percent of the population is zero.
joe rogan
Wow.
matthew walker
Yeah.
joe rogan
Wow.
Zero.
matthew walker
And one of the big problems with a lack of sleep, by the way, is that you don't know you're sleep deprived when you're sleep deprived.
So your subjective sense of how well you're doing with a lack of sleep is a miserable predictor of objectively how you're doing.
So it's like a drunk driver.
joe rogan
Especially with men, right?
matthew walker
Yeah.
Perfect example.
You're at the bar.
You've had six or seven shots.
unidentified
I'm fine.
matthew walker
And you say, I can drive home.
I'm fine.
And your response is, I know that you think you're fine to drive subjectively, objectively.
Trust me, you're not.
It's the same way with sleep deprivation.
unidentified
Mmm.
joe rogan
That's fascinating.
But you're not drunk.
So even though you're impaired, you don't feel like you're impaired.
And you probably have a couple of espressos or one of these caveman coffees.
You feel fine.
matthew walker
Right.
joe rogan
You get juiced up.
You're ready to go.
And you're trying to accomplish things.
You're trying to succeed, right?
You're trying to get ahead in this life.
matthew walker
Yeah.
joe rogan
I don't need to sleep.
matthew walker
And that's completely counterintuitive based on the data.
We know that people are more productive, you know, and we've seen some of these studies in the workplace where you look, firstly, underslept employees will take on fewer work challenges overall.
They end up taking the simpler ones, like listening to voice messages, rather than actually digging into deep project work.
They produce fewer creative solutions to challenges that you give them.
They also slack off when they're working in groups.
It's called social loafing, where they just ride the coattails of other people's hard work.
The less sleep that you have, the more willing that you just sort of don't pull your weight.
Furthermore, it goes all the way up to the top.
So the more or less sleep that a business leader has had from one night to the next, the more or less charismatic their employees will rate that business leader, despite them knowing nothing about the sleep of that CEO. It's evident in their behavior.
joe rogan
Well, because they're short with their temper.
They're quicker to get upset about things.
They're less charismatic and social with their conversations.
Okay, I got it.
I got it.
I got it.
matthew walker
Go to work.
So less sleep does not equal more productivity.
And it's always struck me as strange.
Why do we sort of overvalue employees that undervalue sleep?
And if you look at your workforce, you know, trust me, everyone's gonna be looking busy, but it's like stationary bikes.
Everyone's looking like they're working hard, but there's no forward progress.
The scenery never changes.
That's what an underslept workforce will be for you.
joe rogan
Now, what about the amount of time that people spend at work?
I mean, I know this is not related to sleep, but I've always felt like people work too much.
I feel like you probably could get more done with less time there.
matthew walker
Yeah, so efficiency is what we're talking about, and that's another one of those things with sleep deprivation.
I think many people, when they haven't had a good night of sleep, they're looking at this report and they realize, I've just read this paragraph a third time and I still can't quite get it.
joe rogan
Because your head scrambled.
matthew walker
Efficiency, you know, productivity.
joe rogan
But I would feel like when people are working eight hours a day, I don't think that you could work at peak capacity for eight hours.
At least I don't think the average person can.
matthew walker
No, you can't sustain that.
joe rogan
So you're kind of bleeding these people.
You're getting blood out of a rock in the last couple hours.
matthew walker
And it's, yeah, it's not, you know, either a creative way to work and creativity, you know, is supposed to be the engine of, you know, business and ingenuity.
But why would you, you know, take twice the amount of time to boil, you know, a pot of water on half heat when you could do it in half the time if you just put it on high?
Well, that's sleep.
joe rogan
You know what's interesting, though?
There are certain writers who use sleep deprivation as a strategy for creativity.
Literally don't start like the writers for the sitcom I was on news radio.
They wouldn't start writing until like 2, 3 in the morning.
They would just play video games and fuck around.
And then late at night, they would really start writing.
And they would write until like 7 in the morning.
They would stumble into the set like barefoot, delirious, hair all fucked up with hilarious scripts.
And it's like they had used being silly and overtired as a strategy.
Almost like they were doing drugs.
unidentified
Right.
joe rogan
But they weren't doing any drugs.
matthew walker
I mean, it comes back to, well, we don't know in that scenario, you know, it hasn't been studied, but what we have found, at least in our scientific studies, is that that prefrontal cortex region that we spoke about before, that sort of rational, logical part of the brain, that's one of the first things to go when you're sleep deprived.
So that area of the brain just gets sort of switched off the more that you are sort of lacking in your sleep.
And emotional, deep emotional centers of the brain, which are normally controlled and kept in check by that prefrontal cortex, they just erupt in terms of their activity.
So you're all emotional gas pedal and too little regulatory control break, which for the most part, very bad.
But, you know, one possibility is that if you want to try and get a little bit sort of, you know, Crazy, loosey-goosey.
You know, maybe that's not bad for that type of sort of comedic writing that you, you know, you become a bit more childlike.
And I say that affectionately because the last part of the brain to mature in development is the prefrontal cortex.
So you revert back to almost a more childlike state.
But I honestly would not condone that sort of, you know, undergoing sleep just based on the mortality and, you know, risk of Alzheimer's and cancer by itself.
You just don't want to under sleep.
joe rogan
Even in short doses, like a couple days a week, if sleep is not a renewable resource, what is the effect of, say if you have three nights a week where you sleep eight hours, and then the next night, two hours?
And then the next night, eight hours.
How much of a bump or how much of a dip does that two hours give you in your overall health?
matthew walker
It's bad.
joe rogan
It's bad.
matthew walker
So I'll give you two examples.
There was a study where they just took individuals and they just gave them four hours of sleep for one night.
And what they saw was a 70% reduction in critical anti-canter-fighting immune cells called natural killer cells.
These are wonderful immune assassins that target malignant cells.
So today, both you and I have produced cancer cells in our body.
What prevents those cancer cells from becoming the disease that we call cancer is in part these natural killer cells.
And after one night of four hours of sleep, that is a remarkable state of immune deficiency, and that's one of the reasons why insufficient sleep predicts cancer.
I could also speak about your cardiovascular system, though, and all it takes is one hour, because there is a global experiment that's performed on 1.6 billion people across 70 countries twice a year, and it's called Daylight Savings Time.
Now, in the spring, when we lose an hour of sleep, we see a subsequent 24% increase in heart attacks.
unidentified
What?
matthew walker
In the fall, in the autumn, when we gain an hour of sleep, there's a 21% decrease in heart attacks.
So it's bi-directional.
That's how fragile and vulnerable your body is to even just the smallest perturbation of sleep.
joe rogan
One hour.
matthew walker
One hour is all it takes.
joe rogan
That's insane.
matthew walker
Yeah.
joe rogan
Wow.
That is, you're blowing my fucking mind.
matthew walker
It's frightening.
I mean, you can go even further, by the way.
joe rogan
Wow.
matthew walker
Insufficient sleep will even erode the very fabric of biological life itself, your DNA code.
So in one study, they took a group of healthy adults and they limited them to six hours of sleep for one week.
And they compared the profile of gene activity relative to when those same people were getting eight hours of sleep.
And there were two critical results.
The first was that a sizable 711 genes were distorted in their activity caused by one week of six hours of sleep.
Which is highly relevant, by the way, because we know that many people are trying to survive on six hours of sleep during the week.
I was going to say the second sort of perhaps more interesting result was that about half of those genes were actually increased in their activity.
The other half were actually suppressed.
Those genes that were switched off by six hours of sleep for one week were genes related to your immune response, many of them.
So you become immune deficient.
Those genes that were increased or what we call overexpressed were genes that were related to the promotion of tumors, genes that were related to long-term chronic inflammation within the body, and genes that were associated with stress and as a consequence cardiovascular disease.
joe rogan
This is unbelievable.
You know, it's really disturbing to me in my youth from age probably I guess I was price 18 when I started I delivered newspapers I used to drive around and throw newspapers out of my car and I did it for years and I would have to be up at five o'clock every morning and I never Never went to bed early.
matthew walker
Yeah.
joe rogan
Ever.
And I worked 365 days a year.
matthew walker
How old were you, by the way?
joe rogan
I think I started when I was 18. I might have been 17. Whenever I started driving.
Well, I drove at 16, but I don't think I started right away delivering newspapers, but I was trying to find a good part-time job.
I think I was like either in my senior year of high school or after, I think right after my senior year of high school.
So I was probably 18. Okay.
matthew walker
And the reason I ask, by the way, is because as you go through into those sort of later stages of adolescence and sort of early adulthood, your biological rhythm moves forward in time.
So you want to go to bed later and wake up later.
So even if you went to bed sort of conscientiously at that time, let's say like 10 o'clock or 9 o'clock, you wouldn't be able to sleep because it's biologically impossible.
joe rogan
Yeah, no, I didn't sleep.
And then on Saturday, even worse, one day a week, Saturday night, I'd have to get up at 3 or 4 in the morning because I had to deliver Sunday papers.
And the Sunday papers were enormous.
And so I had to pack a van filled with, because I had 350 people that I would deliver papers to, so I'd have to do multiple trips.
So I'd start work at, you know...
I'd start delivering somewhere around 4.35, depending on when the papers got in, and I was done by like 9, you know, 9.30, and then I'd try to crash, but I was a wreck.
I mean, and it fucked me up for years.
For years I did that.
And I stop and think about that now, listening to you, listening to this conversation, like, what kind of fucking damage did I do to myself over those years?
matthew walker
Yeah, I won't tell you about the stuff with Alzheimer's then and amyloid protein.
joe rogan
Well, I feel okay now.
It's been several decades.
matthew walker
Did I mention that your subjective sense of how well you're doing with insufficient sleepers?
No, no.
joe rogan
Wow, I'm sure.
You did, and I'm sure that there's a factor there.
What's stunning to me is that six hours is so detrimental.
I would have thought that would have been fine.
Six hours is good.
Like, you get six hours, ah, it's good.
That's normal for me.
matthew walker
Yeah.
joe rogan
Like, six hours is normal.
unidentified
Yeah.
joe rogan
Literally the minimum is seven?
matthew walker
Yeah, seven to nine hours of sleep.
joe rogan
Seven you need.
Anything under seven is bullshit.
matthew walker
You really should get eight.
There is a small fraction of 1% of the population that has a special gene that allows them to survive on about five hours of sleep.
And most people, when I tell them this, they say, ah, I think I'm one of those people.
The chances of you being, you know, you're much more likely, for example, to be struck by lightning in your lifetime, the odds of which are, I think, about 1 in 12,500, than you are to have this incredibly rare gene that means you can survive on something around five hours of sleep.
joe rogan
Really?
matthew walker
Yeah.
joe rogan
What is the gene?
matthew walker
Well, it's a gene that seems to promote, again, wakefulness chemistry within the brain that allows you to maintain wakefulness in a more sustained way.
And so we're only trying to understand right now what the actual biochemical mechanisms are in terms of the consequence of that gene, that gene mutation.
But certainly it seems to exist that there are some of those quote unquote short sleepers.
By the way, you know, we hear of these business leaders and even actually heads of state, I'm not going to name any names, but I'll give you right now, but I'll give you two examples of the past.
Margaret Thatcher and Ronald Reagan both were vociferous in their statement and their declaration of how little sleep that they would get.
Both of them said four or five hours a night.
And I think in part it was to paint this heroic ironclad status.
joe rogan
Yeah.
matthew walker
And many people would say to me, you know, Margaret Thatcher, you know, it's your lifetime.
Well, sadly and tragically, Thatcher and Reagan both ended up getting Alzheimer's disease, you know.
And we now know because it's during deep sleep at night that there is a sewage system in the brain that kicks into high gear and it cleanses the brain of all of the metabolic toxins that have been built up throughout the day, this low-level brain damage.
One of those toxic sticky proteins that builds up whilst we're awake is called beta amyloid.
Beta amyloid is one of the leading causes of underlying the mechanism of Alzheimer's disease.
So the less sleep that you're having across the lifespan, the more of that toxic amyloid is building up night after night, year after year.
And I don't think it's coincidental that both of them ended up progressing tragically into a state of Alzheimer's disease.
So it's good night sleep clean in that way in terms of deep sleep.
joe rogan
That is stunning.
Is there anything you can do in terms of how you eat or supplements you can take that could potentially at least somewhat mitigate the effects of having no sleep?
matthew walker
We haven't found any good countermeasures.
joe rogan
Have you tried diet pills?
matthew walker
So people have tried things like ephedrine.
Amphetamines.
Amphetamines.
I mean, caffeine has been used strategically by the military for years.
And caffeine can help you get over the basic reduction in your alertness, so basic response times.
You can dose with caffeine and still maintain some degree of a fast response under conditions of sleep deprivation.
joe rogan
What about ProVigil or NuVigil?
matthew walker
Yeah, so Modafinil is sort of the underlying chemical there.
And it's debated who actually came up with it.
It may have been the French military who actually ended up being the generators of that.
That seems to work through a pathway, at least right now as we understand it, for a chemical called dopamine.
And dopamine is principally known as a pleasure drug.
It's the chemical that a lot of drugs of abuse will target to sort of ramp up.
But it also is a basic alertness drug that when you get an increase in dopamine, you tend to actually get an increase in your alertness and your wakefulness.
joe rogan
Don't you get an increase in happiness as well?
matthew walker
You can too, although modafinil tends to come with the alertness component of that equation and less so with the euphoria.
That's why it has a lower prevalence of sort of addiction and abuse.
joe rogan
Boy, I know a lot of people who...
I wouldn't say they abuse it, but they say they have to use it.
Like, oh, the doctor says?
Doctor says I gotta use it.
And I'm always suspicious.
Because they seem pretty normal, other than the fact that they're exhausted if they don't take this...
What's essentially a stimulant.
I've taken it a few times.
I've taken it when I have to drive like long periods of time like I'm driving from San Diego to California or to Los Angeles and maybe I have a gig.
My gig's done at like 1130. I know I'm gonna be on the road late at night.
I might take one.
And it's fine, but it gives you this weird feeling.
It's a weird state.
And I know a lot of tech people, a lot of Silicon Valley is on this stuff and they pop it like candy.
So much so that Tim Ferriss, when he was writing his book, The 4-Hour Body, he didn't want to include it.
He didn't want to include this particular drug because he felt like people were just going to eat it all the time.
matthew walker
Yeah.
I mean, it's rife throughout student populations.
Study drug as well.
joe rogan
As is Adderall.
matthew walker
Yeah.
And Adderall, you know, one of the interesting things is that if you look at the profile of what sleep deprivation is cognitively, you know, reduced alertness, impulsivity, lack of ability to concentrate, difficulties with learning and memory, difficulties with behavioral problems.
If I were to describe those features to a pediatrician and say, what disorder is this?
Probably say it's ADHD. Yes.
But what we now know is that there is some portion of children out there who are diagnosed with ADHD who either one are just underslept or two actually have sleep disordered breathing because of perhaps tonsil problems where they're not getting sufficient sleep.
And when you treat the sleep disorder, when you do a sort of, you know, remove the tonsils, They start sleeping normally and the ADHD disappears.
So there is an issue here, I think, within that sort of the explosion of ADHD. Not all people are, you know, sort of privy to this sort of sleep problem simply masquerading as ADHD. Some people are.
One of the other problems, too, though, is that ADHD kids tend not to sleep very well.
And what we end up giving them is a drug that is a stimulant which will combat sleep and fight back against sleep.
So I think we need to have a bit more of a strategic approach as to when we think about at least the dose of that medication in terms of when sleep should be sort of expected during the day.
Because, you know, taking it in the middle of the day, in the evening, if it's a stimulant, it's a weight-promoting drug.
We need to be very careful.
Sleep is part of that.
joe rogan
Well, that's terrifying because I don't know if the people that are prescribing these things have the sort of deep education in sleep and the necessity of it that you do.
matthew walker
They don't.
And, you know, it's not their fault either.
You know, and in fact, I've started to try and lobby doctors to start prescribing sleep.
And don't make the mistake that that's me suggesting, you know, prescribing sleeping pills.
That's a separate story.
Sleeping pills are associated with significantly higher risk of death and cancer, and I'm happy to speak about that too.
It was the one chapter in the book that I think the legal team of my publisher took a very long look at.
But I think doctors, to come back to your point, they on average only have about two hours of sleep education in the medical curriculum.
So one third of...
unidentified
Two hours.
matthew walker
Two hours.
One third of their...
joe rogan
This podcast has been two hours.
matthew walker
Yeah.
joe rogan
That's fucking crazy.
matthew walker
Isn't that frightening?
joe rogan
That's terrifying.
And I bet you probably have laid things out better in this podcast than you would get in those two hours of education.
matthew walker
I don't know about that, but I think if...
joe rogan
I'll give you that credit.
matthew walker
If they could increase that, you know, I'm...
unidentified
That's insane.
matthew walker
And I'm desperately appealing for this.
this.
You know, it's a third of their patient's life, but they only get two hours of education.
But the other problem is the medical industry itself, by the way.
You know, their residents, that data, you know, junior residents working a 30-hour shift are 460% more likely to make diagnostic errors in the intensive care unit relative to when they're working 16 hours.
If you have elective surgery, you should ask your surgeon how much sleep they've had in the past 24 If they've had six hours of sleep or less, you have a 170% increased risk of a major surgical error, such as sort of organ damage or hemorrhaging relative to that same surgeon if they had been well rested.
And then the irony here, by the way, is that when a resident finishes a 30-hour shift, gets back into their car to drive home, there is a 168% increased risk that they will get into a car accident because of their underslept state, ending up back in the same emergency room where they just came from but now as a patient from a car crash.
You know, we need to radically rethink the importance of sleep in education, in business, in the workplace, and in medicine too.
joe rogan
Why do they do that to residents?
matthew walker
It's a fascinating story.
So there's a chapter here in the book on this too.
It's a guy called William Halstead.
And he set up the first resident surgical program in the United States at Johns Hopkins University.
And And he was known for being able to stay awake for these heroic lengths of time, days on end.
It's incredible, like superhuman strength.
Turns out that in later years after he died, there was a dirty secret that he was actually a cocaine addict.
joe rogan
That son of a bitch.
matthew walker
And here's what happened.
It wasn't his fault.
Early in his career, he was examining the anesthetic capacities of cocaine.
So, you know, if well, I'm not going to say, you know, you may have heard from perhaps colleagues that when you snort cocaine, you get a numb face.
The reason is because it blocks nerves.
joe rogan
I like how you said it from colleagues.
My colleagues have told me.
I've actually never done cocaine, but I know quite a few people who have.
matthew walker
And they'll have this sort of numbness.
The reason is because cocaine is also a nerve-blocking agent.
joe rogan
Yeah, like lidocaine.
matthew walker
Lidocaine, exactly.
joe rogan
We talked about this yesterday, ironically, on the podcast and about doctors becoming drug addicts, the initial doctors that started doing lidocaine.
matthew walker
Holsted was one of them.
And so he became an accidental cocaine addict.
unidentified
Wow.
joe rogan
So that's why he was up for days.
matthew walker
He was up for days.
And he structured a program where he expected his residents to match him, to go toe-to-toe with him for each hour that he would remain awake.
joe rogan
Yeah, it sounds like what a coke head would do.
Come on, man, stay awake!
matthew walker
Unbelievable.
And I think the story was that he actually knew that it was a problem.
He went to rehabilitation, checked in under a different surname.
And one part of the regiment for him coming off cocaine was to prescribe morphine.
And at the end of the rehabilitation program, he came out with both a cocaine addiction and a heroin addiction.
And so now there's rumors, you know, that he would get his shirts laundered in Paris, you know, in France.
And, you know, they would come back and it wasn't just the white starch, you know, shirts that...
That were in the box.
There were other white substances, too.
But that's, you know, you ask a great question.
Where did that come from?
Where's that history?
The legacy seems to date back to William Halstead, who was an accidental cocaine addict.
And there, we have then maintained that inhumane practice in medicine.
joe rogan
Which is, like...
Yeah.
Absolutely.
unidentified
You're open.
joe rogan
You're operating on people.
matthew walker
And think back to what we said about being awake.
You would never accept treatment from a doctor who started looking at your child who's sick with an appendicitis at 3 a.m. in the morning who then swigs some whiskey and says, yeah, I'm going to do the operations fine.
You would go ballistic.
Well, why do we accept treatment?
You know, after 20 hours of being awake, you're as impaired as you would be if you were legally drunk.
So unfortunately, we placed young residents in this position of, you know, acting and operating and decision-making under conditions of insufficient sleep.
One in five medical residents will make a serious medical error due to insufficient sleep.
One in 20 medical residents will kill a patient because of a fatigue-related error.
joe rogan
One in 20. That's crazy.
matthew walker
And right now, you know, there are well over 20,000 medical residents.
joe rogan
So if you have 100 of them, five are going to kill people.
matthew walker
Accidental deaths.
Think about that number.
joe rogan
That's insane.
matthew walker
If we were to solve the sleep loss epidemic in medicine, you know, we could start saving lives.
And I don't know what it is.
Is it just a, you know, an old boys network?
Well, we went through it.
joe rogan
Yes.
matthew walker
So you've got to go through it.
You know, and the data now is so prolific.
You know, I write all about that and try to build an evidence-based, you know, emotionless cold case for sleep in medicine, a sleep prescription for medicine, as it were.
joe rogan
Well, most people don't realize the requirements that residents have.
matthew walker
No.
And they are literally, you know, beyond human capacity.
Thinking that, you know, hubris and some degree of hours on the job is going to be able to allow you to sort of, you know, cut short what took three and a half million years to sort of, you know, get in place, which is an eight-hour night of sleep.
That's just thick-headed, you know.
And I think the medical profession may be at the stage where it's, my mind is made up, don't confuse me with the facts.
joe rogan
This is blowing me away.
I just don't understand how the very people that are working on the health of patients and fixing them and repairing injuries and taking care of diseases, those are the people that are ignoring one of the primary factors of disease and errors and cognitive function.
matthew walker
It's a travesty.
joe rogan
I have a friend who's an ophthalmologist and he tells a story about during his residency, he was back in the 80s and he had a pager.
He was on the toilet with a tray of food on his lap because he didn't have time to eat and go to the bathroom.
So he's eating food and he fell asleep.
unidentified
Yeah.
joe rogan
And then his pager went off.
And he's like, fuck my life.
matthew walker
I mean, how many warning bells do you need to tell you that you're in a deleterious state if you're falling asleep with your trousers around your ankles, with food all over your face, and yet you're in the deepest stages of non-REM sleep?
joe rogan
And he's the guy who's working on people's eyes.
matthew walker
Yeah.
joe rogan
It's crazy.
matthew walker
Yeah.
And it's, you know, sleep is equally absent for the patient in the hospital, you know, setting.
We know that somewhere between 50 to 70% of all ICU alarms are either unnecessary or ignorable.
And the one place where you desperately need the Swiss Army knife of health that is a good night of sleep is the one place where you get at least, which is on a hospital ward.
We could exit people out of hospital beds earlier.
The data is already there for the neonatal intensive care unit.
They used to leave bright lights on 24-7.
And that would prevent sort of the signaling for sleep and wake and sleep and wake.
And that cycle is critical.
If you regularize light in the neonatal intensive care unit, those infants ended up having higher levels of oxygen saturation because they were sleeping better.
Their weight gain was dramatically increased and they ended up exiting the neonatal intensive care unit five weeks earlier.
joe rogan
Whoa!
matthew walker
Simple things.
You know, why don't we do something like this in medicine?
When you come in onto a hospital ward, you get this on an international flight travel for free, earplugs, face mask.
Even just that by itself could help people to start get better sleep.
Next, on the hospital admission form, Tell me when you normally go to sleep and when you normally wake up.
And to the best of our ability, we as doctors will try to sort of, you know, manage your healthcare around your natural sleep tendencies.
If we could do that, you know, sleep is the elixir of life.
It is the most widely available, democratic, and powerful healthcare system I could ever possibly imagine.
Why aren't we leveraging that and taking it?
That's one of the greatest hacks that medicine could actually, you know, inflect.
joe rogan
That is stunning.
How is this being received, like, by doctors?
Are they reluctant to listen to you?
I mean, what is happening with all this data and your passionate cry for extra sleep or more sleep or the proper sleep, I should say?
matthew walker
It's starting to happen.
I mean, when the book came out, which was sort of the hardback came out back in October, and some people started to give pushbacks sort of in the medicine realm.
You know, there was some concerns about continuity of care, that if you keep switching residents out every 16 hours, that you wouldn't have continuous patient care, and that was a problem.
Well, there are other medical training systems, for example, France, Sweden, New Zealand.
They do this all the time.
They do not allow their residents to undergo anything longer than either a 14- or a 16-hour shift.
They train their residents in the same amount of time or less.
And if you look at the rankings of their medical health systems around the world, they rank far higher than the United States.
So you can't tell me that longer work hours for residents, for example, are necessary to train good doctors.
The evidence just isn't supportive.
So I've had some pushback there.
But for the most part, I think people are receptive once they know the information.
And I think I've been someone who's been to blame here.
I've known this evidence for, you know, I've been doing sleep research now for 20 or so years.
We are with sleep where we were with smoking 50 years ago.
We had all of the evidence about the deathly carcinogenic cardiovascular disease issues, but the public had not been aware.
No one had adequately communicated the science of, you know, smoking to the public.
The same, I think, is true for sleep right now.
That's part of the motivation for why I wrote the book, why I've been doing or trying to do a lot of publicity.
I'm a very shy person.
I don't like being in the spotlight.
But I feel as though there is a mission that whose voice has not been actually gifted yet.
And I wanted to try and help and be a sort of a sleep diplomat.
I mean, that's why I chose the handle on social media, trying to be there as an ambassador for sleep.
And now, once people start to understand the sciences we've spoken about for two hours, then people start to actually realize it's not the third pillar of good health alongside diet and exercise.
It's the foundation on which those two other things sit.
You know, for example, if you're dieting, but you're not getting sufficient sleep, 70% of all the weight that you lose will come from lean body mass, muscle, and not fat.
Your body becomes stingy in giving up its fat when it's underslept.
So once you get this information out there, things are starting to change.
I've started to have some discussions with the World Health Organization.
They seem to be very interested now in getting to grips with sleep.
I'd love to speak to first world governments though.
When was the last time you saw any first world nation have a government-supported public health campaign around sleep?
I don't know any.
We've had them for, you know, drink driving, for risky behaviors, you know, for drugs, for alcohol, for healthy eating.
Sleep should be a part of that equation.
You know, I want to lobby governments to start to instigate this, and it will save them millions of dollars.
The Rand Corporation did an independent survey two years ago on the demonstrable cost of a lack of sleep to global economies.
What they found was that a lack of sleep costs most nations about 2% of their GDP, their gross domestic product.
Here in America, that number.
was $411 billion caused by insufficient sleep.
Solve the sleepless epidemic, you could almost double the budget for education and you could almost halve the deficit for healthcare.
Wow.
joe rogan
What studies, if any, have been done on people who live in the northern hemisphere where they experience these long days like Alaska and Siberia, places like that?
matthew walker
It's really tough for the regulation of the circadian rhythm.
And a lot of people, they're not old, but a lot of people will suffer from what's called seasonal affective disorder, which is the winter blues.
And it's an unfortunate acronym, you know, SAD. Your doctor comes along, you say, look, I'm not feeling good, it's the wintertime.
Well, you're sad.
No, I'm sorry.
It's a medical term.
It's called SAD. It's called Seasonal Affective Disorder.
And that data is quite powerful, too.
And you end up having to use melatonin strategically to help you fall asleep to sort of signal darkness in the summertime when it's really light almost all day.
And then in the wintertime, you reverse engineer the trick.
And in the morning, you sit and you have your breakfast or you're working at your terminal, and you have one of these big light boxes that sits next to you, strong lux power light, to try and sort of fool your brain into thinking that you're getting a lot of daylight when it's, you know, it's not going to be light for the next four hours.
So they have to undergo treatment.
joe rogan
Do they have to do vitamin D supplementation as well?
matthew walker
Some of that too, yeah, because of lack of exposure for the skin to UV light.
unidentified
Wow.
joe rogan
Listen, man, I think you just opened up a lot of people's minds.
You certainly did mine.
I mean, this podcast blew me away.
I thought I knew a little bit about sleep.
I knew nothing.
Thank you so much.
matthew walker
You're so very welcome.
joe rogan
And please tell people how they could read your book.
Where can they get it?
What's your website?
matthew walker
Yes, so I'm all over the social media and the web pages by sleepdiplomat.com.
And the book is called Why We Sleep.
And it is out now on Amazon and all major booksellers.
And that's probably the best way that they can learn all about sleep and frightening the living daylights out of them.
joe rogan
Thank you so much, Matt.
I really, really appreciate it.
matthew walker
You're very welcome, Joe.
Sleep well.
Thank you.
unidentified
You too.
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