The Peter Attia Drive - #221 ‒ Understanding sleep and how to improve it

00:00:00.000 Hey, everyone. Welcome to the drive podcast. I'm your host, Peter Atiyah. This podcast,

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00:00:47.760 here's today's episode. Welcome to another episode of the drive. As we've released so many episodes

00:00:54.660 over the past four years, we realized we've covered a lot of topics in detail. Sometimes it can be hard

00:01:00.140 to kind of keep up and try to piece it together. We also realized that there are listeners today

00:01:03.780 who weren't exactly listeners a year ago or three years ago or four years ago. So we did a test of

00:01:08.660 this idea back in May of 2022, where we did an episode that pulled a variety of clips from previous

00:01:12.800 podcasts, but all on one topic, which was exercise. The feedback we received from that episode was

00:01:17.200 overwhelmingly positive and people asked for more. So this week we're going to do it again. And of

00:01:22.160 course, we're going to pick a different topic. This topic is going to be sleep, probably something

00:01:26.260 we get just as many questions on as frankly, anything else. We put these clips in the order

00:01:31.040 of what we think is the best way to listen from top to bottom. But in between some of the clips,

00:01:35.100 I'm going to provide a little bit of commentary to set the stage. Our hope is that this will not

00:01:38.700 only allow you to understand the topic of sleep better, but also help identify some of the previous

00:01:42.780 episodes in case you actually want to go back and listen to those in more detail. In each of these

00:01:47.620 clips, I'm going to be joined by sleep expert, Matt Walker. Matt has been on the podcast

00:01:51.400 several times, including three AMAs. One thing to note is that some of these clips are from AMAs.

00:01:57.240 So if you're not a subscriber, you'll actually get a sense of what we cover during those episodes.

00:02:01.740 This is still a new concept and this is only our second time doing this. So we really do want the

00:02:05.960 feedback. If you like this, tell us, we'll keep doing it. If you don't, we'll scrap it. So without

00:02:10.620 further delay, I hope you'll enjoy this special episode of The Drive.

00:02:13.960 Firstly, you know, it took Mother Nature 3.6 million years to put this eight hour thing called

00:02:24.960 a night of sleep in place. And within the space of 70 years, if you look at the data,

00:02:30.740 we've lopped off almost 20 to 25% of that. You know, imagine coming along and saying,

00:02:35.880 you know, in the next hundred years, I think what I'm going to do is for the entirety of human

00:02:42.060 society, I'm going to reduce their oxygen saturation by about 20 to 25%. Do you think

00:02:47.800 that's a good idea? And the answer is no.

00:02:51.080 No, it's such a great example. I'll pause for a moment just to tell a funny story that you and

00:02:55.320 I have talked about off mic, which is up until about 2012, I was in the I'll sleep when I'm dead

00:03:00.920 camp. And I know what led to that. It wasn't that there was a very deliberate decision at the end of

00:03:07.640 medical school when a good friend of mine with all the best intentions, who was a year ahead of me,

00:03:12.480 so he was now in at the end of his internship as I was about to begin mine. He said, and this is in

00:03:19.520 the days when we didn't have the 80 hour work week requirement in residency. So we averaged, I think,

00:03:26.260 about 114 hours a week in the hospital. So he said to me, look, Peter, you're signing up for,

00:03:32.880 you know, whatever, five, seven years of this thing. If you spent every moment outside of the

00:03:38.760 hospital sleeping, you would still be tired. The only difference is you wouldn't have any fun.

00:03:43.120 So make sure you live every moment that you're not in the hospital to the fullest. And so for me,

00:03:51.200 that basically meant if I wasn't in the hospital, I was swimming, I was going out with my friends,

00:03:55.800 I was trying to meet girls, like I was doing anything, everything such that during that period of

00:04:01.000 my life. I, I just know, cause I was pretty adamant about recording how much time, like I was very

00:04:06.480 wed to this idea. There's 168 hours in a week. If I'm spending, you know, 114 of them here and I

00:04:11.680 spend this many driving and I spend this many getting groceries and I spend this many swimming

00:04:15.020 and blah, blah, blah, blah, blah. I think I was about 28 hours a week of sleep. So it wasn't four every

00:04:21.560 night because you'd have none and then six and then three and then eight. Like you, you could binge sleep

00:04:28.020 from time to time, but it was pretty much 28 a week. I'll come back to some of the implications

00:04:33.040 of that. But fast forward a few years, I'm talking to a good friend of mine who's a physician who

00:04:37.060 like you is adamant about, you know, the importance of sleep. And we're having dinner one night and he

00:04:42.140 says, he's challenging me on this. And he says, so let me get this straight. You've just decided that

00:04:47.480 you're going to sleep half of what is evolutionarily programmed. And I said, yeah,

00:04:52.660 he goes, does it strike you as odd that evolution would have designed us to spend a third of our

00:04:59.500 life, not mating, not watching out for predators, not hunting for food, but doing this thing for

00:05:08.000 some other purpose? Do you think that thing must've been important? And it was such an obvious

00:05:12.620 argument, but it really overnight changed the way I thought about this, which was evolution went to

00:05:18.440 great lengths to do this and superficially at great cost to us. Right. I mean, you could argue,

00:05:25.780 well, imagine you didn't need to sleep and you could spend 24 hours a day foraging for food or

00:05:30.760 a mate or some other thing, but it didn't. So it's sort of, it's sort of like, there's probably a reason

00:05:36.380 we are not anaerobic to your point about reducing oxygen saturation by 25%. You know, if you were to

00:05:42.420 think about that, you know, during sleep, just as you said, you're not eating, you're not finding food,

00:05:48.440 you're not finding a mate, you're not reproducing, you're not caring for your young, you're vulnerable

00:05:54.020 to predation on any one of those grounds, but especially all of them put together as a collective.

00:05:59.820 It's completely anti-evolutionary.

00:06:01.860 It sounds like the dumbest thing. And, you know, often said, and it has been said before, if sleep

00:06:07.180 doesn't serve an absolutely vital set of functions, it's the biggest mistake that the evolutionary process

00:06:14.200 has ever made. And we now realize from this constellation of evidence that mother nature

00:06:20.920 did not make a spectacular blunder in putting this thing called an eight hour sort of need of

00:06:26.660 sleep in place. It is the greatest life support system that you could ever wish for. It is a

00:06:33.000 remarkable health insurance policy. And what's great is that it's largely democratic. It's mostly free.

00:06:39.780 And in terms of a prescription from a doctor, it's largely painless. So I almost wanted to title the

00:06:47.220 book, consciousness is overrated, or just sometimes dot, dot, dot, consciousness is overrated. But when you

00:06:54.520 really look at the evidence in terms of risk, de-risking just about every disease that is killing us in the

00:07:02.320 developed world, it's very hard to look no further than sleep. And that's why I don't want to trivialize

00:07:09.200 diet. And I don't want to trivialize movement and activity. But what I would say is that if you want

00:07:15.660 to put sleep up against either one of those two and kind of play the whole head to head game, which I

00:07:21.080 don't think we need to do here, I would simply say that sleep is the foundation on which those two other

00:07:28.180 things sit. It's not the third pillar of good health. I think it is the foundation.

00:07:32.000 That's a really interesting way to think about it, because I typically describe four pillars,

00:07:36.760 or five if you include all of the exogenous molecules that you could lump together. But another way to think

00:07:43.100 about it, which again, I don't think is necessarily the right way to think about it, but sometimes it makes the

00:07:47.240 point. If you deprive yourself of food, how long can you survive? Well, we have one person up to 382 days.

00:07:55.860 Even someone who's as lean as you could survive 30 days with no food. How long could you survive without water?

00:08:02.100 Depends greatly on the temperature, et cetera. But you could make the case that deprivation of sleep

00:08:08.920 would result in the quickest reduction of health, certainly more than not eating or not exercising

00:08:15.600 for a period of time. And those studies have been done in rats. Yeah. And actually, we know some of

00:08:20.340 this from humans who have been trying to... In fact, didn't the Guinness Book of World Records,

00:08:24.360 I can't remember if I read this in your work, they've actually banned attempts at longest period of

00:08:30.520 sleep deprivation. So I mentioned this. Yeah. There was a time when you could still try and beat the world record

00:08:36.060 of sleep deprivation. And it got up to about sort of, I think the last true effort was about 24 days.

00:08:44.340 But I think it was debatable, that one. But based on the weight of the scientific data, the relationship

00:08:51.300 between sleep loss and mental health, sleep loss and cancer, sleep loss, cardiovascular disease,

00:08:58.980 sleep loss and metabolic syndrome, Guinness started to feel very, very uncomfortable. And then when

00:09:05.260 suicide came on the table, it pulled it. So in other words, think about this. You know, there was a

00:09:10.920 gentleman, Felix Baumgardner, I think his name was, who, sponsored by Red Bull, went up in a capsule,

00:09:17.240 in a hot air balloon, to the outer surface of our planet. This was about four years ago. This was remarkable.

00:09:23.180 He opened the door, and then he jumped out. And he fell back down to Earth at over a thousand kilometers

00:09:32.000 an hour. Using his body alone, he broke the sound barrier. And he successfully came down. And now Guinness

00:09:39.440 says, for that, just fine. However, to sleep deprive yourself, no, much more unsafe. We're not going to

00:09:50.720 let it happen. You are allowed. Just to put it in context. You're allowed up to 12 jumps off Niagara

00:09:56.100 Falls. Basically. But that's okay. But no, no, you're not going to. That's such a great point.

00:10:00.380 So let's shift gears just a little bit and go back to the polysom. Let's explain to people,

00:10:12.820 because we're going to eventually have to talk about tracking these things. And I want to bring

00:10:17.640 up some of the sort of commercially available ways that people do that, which I think by definition

00:10:22.520 are still not accurate enough for people to, you know, compare them to their polysom. But

00:10:27.540 if I came into your lab tonight, and I was willing to go to sleep there, and you would hook me up to

00:10:33.820 an EEG, what are the different patterns of brainwaves? And how would you morphologically describe them and

00:10:40.240 then bucket them by these stages? You've already sort of touched on a little bit as deep REM, deep REM,

00:10:47.020 deep non-REM, et cetera. Yeah. So upon falling asleep, human beings, and in fact, all mammals will

00:10:55.320 experience two different stages of sleep. One of them is called non-rapid eye movement sleep. The

00:11:00.120 other is rapid eye movement sleep. Non-REM sleep has been further subdivided into four separate stages,

00:11:06.680 which are unimaginatively called stages one through four. Thank God.

00:11:11.380 Yeah, I know. Yeah. I think that's all that the sleep deprived people who are, you know,

00:11:15.300 experimenting could come up with at that time. So increasing in their depth of sleep sleep. So

00:11:21.200 stages three and four of non-REM sleep are the really deep restorative stages of sleep. Stages

00:11:27.280 one and two are the lighter stages of sleep. And then on the other hand, we have rapid eye movement

00:11:32.400 sleep or REM sleep, which is named not after the popular Michael Stein pop band, but because of these

00:11:38.500 bizarre horizontal shuttling eye movements that occur during this stage of sleep, these rapid eye

00:11:43.480 movements. So you have these two different types of sleep, and they will essentially, as you fall asleep,

00:11:51.200 here in at the sleep center at Berkeley, they will go into essentially a battle for brain domination

00:11:57.480 throughout the night. And that cerebral war between non-REM and REM is going to be won and lost every

00:12:05.020 90 minutes and then replayed every 90 minutes to create what we call a standard cycling architecture

00:12:12.480 of sleep, or what we call a hypnogram of sleep. And so what you will see is that upon falling asleep,

00:12:19.080 you'll go into the light stages of non-REM stages. Before we do that, let's say before I fall asleep,

00:12:23.820 when I'm just laying in the bed, how would you describe my brainwaves under the wakeful condition?

00:12:29.520 So at that point, what we typically see is that when you close your eyes, the back of the brain goes

00:12:34.700 into what's called an alpha rhythm. So when you're awake, your brain shows this remarkably frenetic,

00:12:41.360 high frequency electrical activity. In other words, your brain is going, in terms of its brainwaves,

00:12:47.160 it's going up and down many, many times a second. And the amplitude is...

00:12:52.900 And the amplitude is very small, which kind of is paradoxically, you think, if I'm awake,

00:12:58.220 then my brain is active. And so the size of those brainwaves should be big. It's not. It's actually

00:13:03.620 very small. And here's the reason. Different parts of your brain are doing different things at

00:13:09.500 different times. So those brainwaves sort of are all canceling each other out. So the analogy would

00:13:17.240 be, if I were to dangle a microphone above a sports stadium, what I'm picking up is the signal from the

00:13:24.780 crowd of 100,000 individual neurons that sit underneath it. That's how an EEG electrode is.

00:13:31.680 Now, before the game starts, that's wakefulness. And at that point, the 100,000 people in the

00:13:39.420 stadium, the 100,000 brain cells, they're all speaking to each other at different moments in

00:13:44.700 time.

00:13:45.260 So there's a lot of cancellation.

00:13:46.340 So there's a lot of cancellation. They're not all coordinated, but it's very fast and frenetic.

00:13:51.420 So I just get this signal that is very desynchronized and it's not synchronous. So they're

00:13:57.760 not summing their power together. So the size of that brainwave is not very big, but it's going

00:14:04.200 up and down.

00:14:04.500 But that's why the frequency is so high.

00:14:05.740 The frequency is high, meaning that you're sort of going up and down maybe 50, 60 times per second.

00:14:12.860 Now, as you start to fall asleep, or actually even before you start to fall asleep, as you're lying in

00:14:18.380 bed awake, the back of the brain is the first part of the brain that really starts to settle down.

00:14:23.900 It goes into what we call alpha rhythm when you close your eyes.

00:14:26.920 And I assume that's just because the occipital cortex is in the back and you've closed your eyes.

00:14:30.900 Brilliant. So the back of the brain, visual brain, if you close your eyes, that part of the brain

00:14:35.880 essentially stops processing the outside world. And it goes into its sort of default state when it's

00:14:42.300 awake of slowed frequency. It drops down from maybe 50 times per second down to about, let's say,

00:14:49.660 10 cycles per second.

00:14:51.480 But still relatively low amplitude?

00:14:53.180 But still relatively low amplitude. Then once you start to actually transition, when you make

00:14:59.920 that bridge from the world of wakefulness to sleep, as you sort of cross through that window

00:15:06.020 from one of those worlds to the next, something bizarre happens. And if anyone out there is lucky

00:15:12.000 enough to be listening to this and they have a bed partner, you can actually see this. Just look at

00:15:17.940 their eyelids as they're falling asleep. And what you'll see is that their eyeballs start to roll

00:15:24.280 in their sockets and they're called slow rolling eye movements. Now we don't know why the eyes roll

00:15:31.120 in the sockets like that, but it's the first sign that you're making the transition from the world of

00:15:37.060 wakefulness into sleep. We use it as almost an indicator of the transition into sleep. Now, by the way,

00:15:42.660 if your partner wakes up, sometimes people will wake up from that state and they see you just looking

00:15:48.080 over them in bed, staring at their eyelids. If you're in early in a relationship, it's usually the

00:15:54.500 end of the relationship. That's just a point of note. Please don't blame me. Usually wait till you're

00:15:59.020 married and then start to do that one. The divorce usually is harder to come by. So then you start to go

00:16:05.400 down into the light stages of non-REM sleep, stages one and two. Then after about 20 or so minutes,

00:16:11.940 you'll go down deep into stages three and four of non-REM sleep. And in one and two, have we

00:16:17.640 transitioned out of that alpha wave? I mean, where do we start to see the thetas and... Theta already

00:16:24.120 happening in stage one. In stage two, you actually go into theta activity, which is now down from 50 cycles

00:16:31.900 per second, maybe down to just sort of six or seven cycles per second.

00:16:37.720 And the amplitude's getting a bit bigger, isn't it?

00:16:39.480 It is getting a bit bigger, yeah. And then every now and again during stage two, the way that I know

00:16:44.100 that you're in this lighter stage of non-REM sleep stage two is that you'll get these synchronous

00:16:49.780 bursts of electrical activity that we call sleep spindles.

00:16:53.440 That's the K-spindle.

00:16:54.560 And that's sort of, yeah, where you get this... Actually, you get a nice big slow wave,

00:16:59.020 almost like a single slow wave. And then you get this burst of a sleep spindle. And we actually did

00:17:04.840 this great project here at the Sleep Center where we did the sonification of sleep. And we extracted

00:17:10.580 brainwaves from human beings. And then we sort of smoothed them a little bit with some sort of audio

00:17:17.200 software. And then you can play them back. And it's beautiful because when you hear these sleep

00:17:23.600 spindles, they are these short synchronous bursts of electrical activity that lasts for about

00:17:28.800 a second and a half. And they go up to about 10 or 15 cycles per second. So it's almost like

00:17:35.380 that beautiful rolling R in sort of in the Hindi language, you know, sort of like a cat pairing.

00:17:41.860 So you get these big slow waves and then you get this ripple of a spindle. And when you hear it

00:17:47.660 on the speakers, it's just sensational. You get this, you know, it's every time I hear it, I mean,

00:18:00.240 this is spine tingling stuff when you realize this is going on right now, physiologically in someone's

00:18:06.320 brain. And then from there, you start to go down to the really deep stages of non-REM sleep stages three

00:18:12.720 and four. And at that point, the brain goes into this incredible synchronous mantra chant of these

00:18:20.700 slow waves. So the brainwaves slow down, you go down to maybe just one or two cycles per second,

00:18:28.540 very, very slow brainwave activity. But the size of those waves crashing on the beach of the cortex,

00:18:34.880 as it were, they are huge. And the reason is this, go back to the sports stadium analogy.

00:18:40.480 Let's say that we're here at Berkeley and we're playing Stanford arch rivals.

00:18:44.900 Yeah, which hopefully you're going to kick their butt.

00:18:46.680 Fingers crossed.

00:18:47.360 Just make sure there's no band anywhere to be found.

00:18:51.300 It always does us a terrible deserve. But at that point.

00:18:54.680 They're chanting in unison.

00:18:55.680 They're all chanting in unison.

00:18:56.800 So it's louder, but they're now making the same sound together and you can actually hear what's being

00:19:04.200 said.

00:19:04.700 Exactly. So now in that single microphone, you can hear Stanford sucks.

00:19:10.200 Stanford sucks. So all of a sudden, all of the reasons that we are only now starting to

00:19:16.600 understand, the brain coordinates hundreds of thousands of neurons, unlike it does at any

00:19:24.420 moment elsewhere in the 24 hour period. Hundreds of thousands of brain cells all decide to join

00:19:31.380 hands, as it were, physiologically, metaphorically, and they all fire together and then they all go

00:19:37.600 silent. They all fire together and then they all go silent.

00:19:40.960 And what I find amazing about that, by the way, is how slow that frequency is. You're basically,

00:19:45.640 you could be, this could be only happening once a second, right?

00:19:49.000 That's right. And that's why it got a terrible rap for 20 or 30 years, because it actually looked

00:19:55.000 not dissimilar to some aspects of coma. That's how slow those brainwaves were. So sleep scientists

00:20:01.320 were, you know, understandably fooled into thinking that deep sleep was a time when the brain essentially

00:20:07.280 was just doing nothing. Now we realize the exact opposite is true because it's during that deep

00:20:15.460 sleep that you get essentially information transfer within the brain. It's a file transfer mechanism.

00:20:22.320 And the way to think about this is, let's say it's like long wave radio. If you're in the city,

00:20:28.020 you tune into FM, which is short wave radio, you can pick up a bunch of signals. Then the further

00:20:32.200 you drive out into the desert, let's say here in California, you just lose those channels because

00:20:36.420 the range from the tower is so short that you just lose that range. But if you go on to sort of,

00:20:43.600 you know, the long wave radio stations, you can still pick up stations for hundreds of miles. Why?

00:20:48.940 Because the carrier frequency of those radio waves is much slower. And so the distance over which

00:20:57.040 you can transfer information is much further. Deep sleep is a brain state of long distance

00:21:05.060 information transfer. Is there morphologically a difference that you can see between stages three

00:21:11.540 and four, which are obviously both delta waves, but how do you distinguish those two?

00:21:17.560 Technically, no. The way it's defined is that what proportion of a 30 second period of time,

00:21:23.540 and that's the way that we score sleep. I'll have you sleep for eight hours, then I'll chop up that

00:21:28.380 eight hours into 30 second bits of information. And for each 30 seconds, you'll get a sleep score,

00:21:34.100 and then we add them all up. And what differentiates stage three of deep non-REM sleep from the very

00:21:41.220 deepest stage, which is stage four non-REM sleep, is simply what proportion of that 30 seconds

00:21:48.020 is consumed by that deep slow brainwave activity. If it's sort of less than 50%, then it's stage three.

00:21:56.860 If it's more than 50%, stage four. So morphologically, no. Although if you really look at it morphologically,

00:22:06.780 on average, yes, the waves are typically larger in amplitude and slower in frequency in stage four

00:22:15.680 than they are in stage three. And do people always progress monotonically through these?

00:22:21.260 Or do sometimes people go one, two, four, three REM, for example?

00:22:25.680 No.

00:22:26.340 You have to go through three to get to four?

00:22:28.360 You have to go to three to get to four. You have to go from two to get to three to get to four.

00:22:35.060 With the exception of probably, let's see, two examples. One is pathological. If you suffer

00:22:41.980 from narcolepsy, one of the things that typically happens is that you go from being awake straight

00:22:47.800 into REM sleep. So to sort of finish the 90-minute cycle, and this will make sense, you go sort of

00:22:54.040 stage one to stage two, stage two, three, three, four. Then after about 70 minutes, you'll rise back up

00:23:00.740 into stage two. And then finally, you'll pop up into REM sleep. And then you'll have a short REM sleep

00:23:06.900 period. And then you'll go back down again, down into non-REM sleep, up into REM, down into non-REM sleep,

00:23:12.920 up into REM. And you do that, as I said, every 90 minutes. However, what changes is the ratio of

00:23:20.600 non-REM to REM within that 90-minute period as you move across the night, such that in the first half

00:23:28.500 of the night, the majority of your 90-minute sleep cycles are comprised of lots of deep non-REM sleep

00:23:34.520 and very little REM sleep. But as you push through to the second half of the night,

00:23:39.640 now the seesaw balance changes. And the majority of those sleep cycles are comprised much more of

00:23:45.200 rapid eye movement sleep and almost no deep sleep. And that's why it's always dangerous when people

00:23:51.240 say, you know, I'm one of those who survives on, you know, six, six and a half hours of sleep at night.

00:23:55.600 I wake up, you know, five, 5.30 to get a jumpstart on the day. And you can ask, well, let's say you're

00:24:02.100 getting six hours of sleep. How much sleep are you losing? And they will say, well, according to

00:24:07.240 your definition of eight hours of sleep, well, I'm 25% off because I'm getting, I lose two hours at

00:24:13.140 the end of an eight hour night of sleep. So I'm sleeping 75%. I'm losing 25%. Yes and no, because

00:24:20.320 yes, you're disproportionate. Exactly. So yes, you're losing 25% of total sleep, but you could be losing

00:24:26.180 up to 70% of all of your REM sleep because it's the REM sleep rich phase that you are shortchanging

00:24:33.720 to get a jumpstart on the day. So you've got to be very careful when you try to think of your sleep

00:24:39.020 dynamics. But to come back to your point, sorry, yes, you always have to go through that linear

00:24:43.200 progression. Narcolepsy is a standout case there. You'll usually go from wakefulness sometimes

00:24:48.120 immediately into REM sleep. Very frightening. Most people don't experience, you know, logical,

00:24:54.380 rational waking consciousness, and then go immediately into irrational hallucinogenic

00:24:59.760 consciousness, which is what REM sleep is. It's very disturbing when you speak to these patients.

00:25:04.740 The other is if you are horrifically REM sleep deprived or chronically sleep deprived,

00:25:10.540 occasionally you can make the transition straight into REM sleep. We see this in people who are

00:25:15.700 abusing alcohol heavily, who are alcoholics. Alcohol and will come onto this, blocks your REM sleep.

00:25:21.140 You can build up such a hunger for REM sleep that the brain says, well, tonight I'm going to forego

00:25:27.280 the non-REM sleep. I'm just going to go and feast on REM sleep straight away. There's hysteresis in the

00:25:31.800 system, maladaptively so. That's a bad sign when you get hysteresis like that, that type of pressure.

00:25:42.400 Matt, last time we sat down, you talked briefly about the sleep chronotypes. And I've found this

00:25:47.920 interesting for basically two reasons. One is just observing probably a migration in my own daughter's

00:25:53.760 chronotype, which is as she's getting older, she's sleeping in longer in the mornings and going to

00:26:00.320 bed later and later. And I know that as she gets closer and closer to being a teenager, that's probably

00:26:05.260 going to increase. But also just more cognizant, I think, of other people. You alluded to it briefly

00:26:11.200 earlier, which is like there are just people who are going to go to bed later and wake up later. And

00:26:14.980 it doesn't mean that there's anything wrong with that or there's anything wrong with the reverse,

00:26:19.580 which is people who go to bed early and wake up really early. So kind of wondering if there's a

00:26:25.560 way to actually know what chronotype you are beyond just observation, because is it possible that the

00:26:34.300 observation is not your optimal state? In other words, if you have somebody who's sleeping a certain

00:26:39.860 way, because their job is imposing it, but it's not the way that they're, you know, ideally meant to

00:26:45.320 do it. Let me give a better example. A student in college could easily drift into a later chronotype

00:26:52.800 because everybody in their dorm room is, even though they may actually be more suited to be earlier. So

00:26:59.140 how can one figure this out?

00:27:01.640 So there are genetic tests that will give you a stronger sense of your chronotype. So chronotype simply

00:27:09.240 means, yeah, are you a morning person? Are you an evening person? Are you somewhere in between?

00:27:14.600 And somewhere between 25 to 30% of the population are morning types, 25 to 30% are evening types,

00:27:22.000 and then the rest of us are somewhere in between. Sleep science has then gone a little bit further.

00:27:27.480 We split it into five categories sometimes, which is extreme morning types, morning types,

00:27:33.240 middle evening types, and extreme evening types. We know that it is under strong

00:27:39.160 genetic control for two reasons. First, there is a significant degree of heritability. So if you

00:27:46.760 are a morning type, it's more than likely that one or both of your parents were morning types.

00:27:52.700 Secondly, we now know that there are a collection of genes that will determine to a degree your

00:28:00.280 chronotype. And this is why companies like 23andMe will tell you what type you are, or they will give you

00:28:06.700 a probabilistic estimation of what type you are. Last count, I think, from data from 23andMe and

00:28:13.820 this data from the UK Biobank, there's about nine different genes that we know of right now that

00:28:20.040 will contribute to your chronotype. Most of them are what we call clock genes. This refers to the fact

00:28:27.200 that these genes control the rhythm of your circadian cycle. Now, those genes don't control necessarily

00:28:35.800 the size of your circadian rhythm. In other words, how strongly active and awake you are during the

00:28:43.320 day and how deeply down you go at night. These genes do something different. These genes control

00:28:50.940 when that sinusoidal wave of your circadian cycle arrives on the clock face. What I mean by that is

00:28:58.680 if you have a certain type of gene complement that makes you a morning type, your activation peak,

00:29:08.720 your peak alertness is going to arrive earlier in the day and your awesome downstroke of your

00:29:15.120 circadian rhythm will arrive earlier in the evening. Whereas if you have a different combination of these

00:29:22.620 gene composites, then you could be an evening type. In other words, your circadian rhythm looks very

00:29:29.380 similar in its sinusoidal pattern, but when the peak and the trough of that circadian rhythm arrive

00:29:36.680 on the 24-hour clock face is very different to a morning type. So we know that there is a complement of

00:29:45.420 genes that you are given at birth that will determine, on average, once you're an adult, are you a morning

00:29:51.600 type or are you an evening type? What you alluded to, however, for your daughter was something

00:29:56.940 different, which is that no matter what chronotype you are, that innate chronotype rhythm that you have

00:30:05.020 gifted by your genes will change as you develop from a young child to an adolescent teen to an adult

00:30:13.760 to an older adult. In other words, you go from being much more of a morning type when you're a kid,

00:30:19.620 even though you want to stay awake longer, you're found on the couch and you're carried to bed and

00:30:24.080 you're fast asleep, to them being a teen where your chronotype fast forwards in time. And this is a

00:30:30.980 problem for early school start times where you're putting kids to bed at 9 p.m. and saying you've got

00:30:35.600 to go to bed because you have to wake up at 5 o'clock in the morning to catch a 5.30 bus for a 7.15

00:30:41.240 start time. Well, there's no point in saying that. It's not their fault that they're now in bed and it's

00:30:47.200 10.30 an hour and a half later and they can't fall asleep as a 15-year-old because their chronotype

00:30:54.000 has moved forward in time. They want to go to bed later and wake up later. Nothing they can do about

00:30:59.340 it. It's biology. And then once they become an adult, it starts to shuttle back a little bit once

00:31:05.360 they become sort of, you know, moderate age, 30 or 40. And then as we start to get older, we regress.

00:31:11.460 That's why in Florida, there's something called the early bird special where people are going out

00:31:17.120 for dinner at, you know, 4 p.m. or 5 p.m. because their chronotype has regressed back and they're in

00:31:23.140 bed by, you know, 8 p.m. So there are genetic tests to come back to your question. However,

00:31:30.360 you don't need to do a genetic test to get close to understanding what you are. There is a pencil and

00:31:35.620 paper method that sleep scientists have developed and you can Google it. It's called the MEQ test.

00:31:43.320 And maybe I'll send you the link and we can put it in the show notes.

00:31:46.200 Yeah, we'll put it in the show notes.

00:31:48.140 And it's a very simple link that you just click and it's a test. It probably takes about

00:31:51.560 five or six minutes to fill out. And it's called the MEQ test, the morning eveningness

00:31:58.600 questioner test. And you go through, you answer a list of questions. And at the end,

00:32:03.640 you add up your score and it will tell you what flavor of chronotype you are. And what's nice is

00:32:09.360 that then they've pattern matched this test and validated it against these genes, these genetic

00:32:15.980 tests. And there's a pretty good correlation. It's not too far off. So this is the poor man's

00:32:21.540 version of the 23 and ME test if you want it. And we'll do a link in the show notes and you can take

00:32:27.900 it. And that's a cheaper way, a pencil and paper method or an online method.

00:32:31.760 So the bigger question is, Matt, what do we do with this information, right? I mean, you've

00:32:35.580 I think we did talk about this previously at one point that you have a couple who have different

00:32:41.440 chronotypes that can be really difficult. They're going to bed and waking up at different times.

00:32:45.960 You've already alluded to the problem of children who are, I think, being subjected to potentially

00:32:52.320 too much early school when in reality they probably would do better with later school.

00:32:57.140 Is this the kind of thing that should factor into decisions people make about when they pick

00:33:02.080 classes in college? Like, I mean, it seems like there seems to be this seems to be one of those

00:33:06.500 things where there might be a bunch of people that go through life kind of miserable when they don't

00:33:09.980 have control over their schedule as opposed to knowing this. And so would knowing this by itself

00:33:16.220 provide a benefit to folks?

00:33:18.460 I think it would. I think it would explain a lot about why you struggle so much where other people

00:33:24.700 seem to be just these energizer bunnies and they've even got time to go to the gym for an hour before

00:33:29.860 they sit down at their office desk at 7 a.m. in the morning. And you're still on your fourth cup

00:33:36.520 of coffee desperately trying to wake up and you're struggling to make it in by 7.15 having woken up

00:33:41.720 20 minutes before. And I think the second thing that it helps with is realizing that you're not

00:33:49.300 culpable. It's sort of non-mea culpa. It's not your fault. You can understand that this is genetic

00:33:56.800 because a lot of night owls have gone throughout life being chastised and thinking, well, if only I

00:34:02.560 could get my act together and get to bed earlier and stop being what people tell me I am, which is

00:34:08.680 slothful or lazy. You know, I could hold down a better job. And again, I think society needs to be

00:34:16.360 much more understanding of it and also then modifying itself in response to accommodate it.

00:34:25.180 And neither of those things I see in full serving scoop sizes in society right now. And that should

00:34:32.380 change. And I think COVID is interesting because if there's some positive upside to it, it may have

00:34:38.100 given us the chance for people to understand how much better they can sleep when they're closer in

00:34:44.300 harmony with their own chronotype rather than trying to work against it. Because when you fight

00:34:49.700 biology, you normally lose. And the way you know you've lost is often through disease and sickness.

00:34:55.740 And I think there is a version of that going on here. I also think it can sometimes explain

00:35:02.260 incorrect insomnia. Often I'll hear someone tell me if I'm sort of out in the public,

00:35:08.860 they'll say, well, I suffer from insomnia. I get into bed and I can't fall asleep and I'm wide awake

00:35:15.380 for the first hour and a half and I need to take some sleeping pills. And then I'll say, you know,

00:35:22.240 firstly, I'm not a doctor, but let me just ask you a question. If you were on a desert island with no

00:35:27.760 responsibilities, nobody to wake up for, nothing to do, and you could just sleep whenever you want and

00:35:33.520 get up whenever you want. What time would you normally go to bed? And they would say, well,

00:35:38.020 I would actually like to go to bed at midnight and wake up around eight o'clock in the morning in truth,

00:35:43.400 but I have to get up for my job. I have to wake up at six. I'm getting in bed at 10,

00:35:48.540 but I still have this terrible insomnia. And I say, well, you know, I don't know this,

00:35:53.200 but it's possible that what you could have is not insomnia, but a mismatch between your chronotype

00:35:59.020 and your working life schedule. And you may want to explore some of this. And there's a test,

00:36:04.180 an MEQ test, and I tell them about this and then go and speak to your doctor. So that's the second

00:36:08.660 implication that I think comes from the question that you asked about how it impacts society.

00:36:14.020 Once you know it, what do we do about it? And what should we be doing about it?

00:36:18.360 Those are some of the ramifications I think.

00:36:20.300 I forgot to say in the episodes before, and I'd love to say it now is about sleep opportunity versus

00:36:33.200 duration. We've constantly been speaking about in our discussions, how much sleep does a person need?

00:36:37.980 What's the optimal amount? And we're speaking about somewhere between seven to nine hours.

00:36:42.640 When I say that, I'm talking about seven to nine hours of sleep.

00:36:47.060 Not time in bed where you might lose 10 to 15% of it.

00:36:51.980 Right. And this is the reason that when I think people who say, well, surely you can get by on

00:36:57.360 six and a half hours of sleep or seven hours of sleep. You've got to be very careful because that's

00:37:01.660 a dangerous statement. This comes to something that we call sleep efficiency. Now, if you are in your

00:37:06.960 forties, you will probably have, if you're healthy, you'll probably have a sleep efficiency of what we

00:37:12.320 call 90%. In other words, of the time that you're in bed, 90% of that time is asleep and 10% of the

00:37:20.340 time is awake. So let's take an eight hour sleep period. And you think, well, I'm in bed for eight

00:37:26.960 hours. So I'm good. I'm getting my eight hours of sleep. That's not true. Eight hours of sleep is

00:37:32.880 what that's 480 minutes. If my math is correct. If you get a 10% loss of efficiency, it's like a

00:37:40.620 heating system. You lose 10% of it. You're down to seven, 12, you're down to seven, 12. So in other

00:37:45.840 words, for you as a 40 year old with a healthy sleep efficiency of 90%, for you to get eight hours

00:37:52.320 of sleep, you need to be in bed for eight hours and 48 minutes. Even a bit longer actually. Yeah. Or

00:37:57.980 even a bit longer. So you've got to be very careful. That's why I constantly speak about a

00:38:02.620 sleep opportunity of eight to nine hours in bed to get your seven to eight hours of total sleep,

00:38:09.260 if that makes sense. Yeah. And this is where I think devices like the Oura Ring are very helpful

00:38:13.040 because that's where they're very good. They're very good at telling you, you were in bed this long,

00:38:18.160 but you're actually only asleep this long. And that's the number we want the patients to fixate on.

00:38:22.820 We don't even look at time in bed when we give our patients feedback. We're talking about

00:38:26.820 total sleep time and efficiency. So if there's a problem with total sleep time and efficiency is

00:38:33.220 low, you have to improve the quality. If total sleep time is low and efficiency is high, you need

00:38:39.420 more time in bed. And it's getting people to understand that distinction. That's very important.

00:38:43.500 And the caveat that comes for people with insomnia though, that I'm here saying you need to increase

00:38:49.920 your time in bed, your sleep opportunity, as I call it, to make sure that you get the right total

00:38:55.060 amount of sleep. And you have to accept there's inefficiency in the system and you need to extend

00:39:01.520 your time in bed to overcome that slight inefficiency. So again, sort of eight hours and

00:39:07.240 15 minutes to get your eight hours total sleep. The only time I would say that you should not be

00:39:12.460 thinking about longer time in bed is if you're someone who is struggling with insomnia and you're

00:39:17.660 lying in bed awake a lot of the time. Reprogramming.

00:39:20.820 We actually do the opposite, which is we actually shorten your sleep opportunity. We crunch that

00:39:26.620 down. It's one of the tools that we have in the CBTI toolbox.

00:39:29.280 That's right. So you want to drive the efficiency up by taking the denominator out.

00:39:33.120 People have lost their confidence in going into the bedroom and sleeping constantly soundly throughout

00:39:38.620 the night. So what we end up doing is actually constraining them maybe down to just six hours of

00:39:43.620 sleep opportunity. We put them on a diet of sleep opportunity rather than an extension.

00:39:48.720 And very quickly what happens, so it's ironic, you come to me and you say, I'm not sleeping well.

00:39:54.160 And I say, great, I'm going to have you sleep less. And you say, ridiculous. It's not. What you do is by

00:39:59.780 compressing that window down, you're sleeping less and you're building up more of that sleep pressure

00:40:06.660 because as a consequence of the reduction of sleep opportunity time, you're going to be awake during

00:40:11.920 the day longer. The longer that you're awake, the more of that sleep pressure you build up.

00:40:16.720 So firstly, you're coming into the following night with even more sort of sleepiness on your

00:40:23.440 shoulders. And then secondly, I'm teaching the brain, unlike it's been given, it's been given

00:40:30.040 luxury time to just be awake as long as it wants to at night and maybe sleep some. And that's that

00:40:36.000 phenotype of insomnia, awake time at night. By constraining that time, I start to force your brain to

00:40:42.840 realize, I'm sorry, you no longer have the luxury of having all of this time to sort of be awake and

00:40:49.420 be asleep. And very quickly, the brain starts to realize and learn that in fact, it only has this

00:40:56.640 tiny opportunity at the dinner table called sleep that is six hours. And now you start to brute force

00:41:04.440 efficiency. The brain starts to realize, my goodness, I've only got six hours. I need to get

00:41:11.240 my sleep into that six hours. So efficiency markedly increases when you constrain total amount of time

00:41:19.840 in bed. So it's this ironic way that we help treat insomnia. We constrain total sleep time,

00:41:26.640 you brute force efficiency and a brute force response from the brain. And all of a sudden,

00:41:32.180 something magical happens. Now that we've set the stage for what sleep is and why it's so important,

00:41:43.080 the next set of clips will really look at ways in which we can improve sleep. These clips will look

00:41:47.980 at the pros and cons of napping, proper sleep hygiene, and an ideal wind down routine, optimal

00:41:53.180 temperature for sleep and how Matt changed his thinking on blue light.

00:41:56.180 The question now comes down to one of napping, which we did touch on in our previous episode,

00:42:07.340 but I want to revisit it. Lots of times patients come to me and say, Peter, you have no idea what

00:42:13.840 a 20 minute nap does for me between two and four o'clock in the afternoon. And my historical response

00:42:21.380 to that has been, you know, gosh, you really shouldn't need a nap. I mean, if you're sleeping

00:42:26.320 correctly, isn't that actually a negative thing because it's depleting some of that adenosine

00:42:31.440 based pressure. And wouldn't you be better off letting the pressure cooker cook and driving you

00:42:37.540 into a deeper sleep when you first take your sleep? So what are your thoughts on that type of a nap,

00:42:45.180 that sort of short 20 minute, you know, late afternoon pre-dinner nap?

00:42:51.540 Naps really are a double-edged sword. And we've done lots of studies where we use naps to study the

00:42:58.640 functions of sleep and we see benefits from naps. Even naps as short as 17 minutes can produce learning

00:43:04.760 and memory benefits. So there does seem to be some enhancement that you get. And you can see that

00:43:10.820 from cardiovascular benefits as well. The downside of naps is that it can take away just what you

00:43:19.960 described, which is sleep pressure. And so the typical recommendation that we have is the following.

00:43:25.300 If you are struggling with sleep at night, avoid naps during the day, because what you want to do,

00:43:33.380 if you are already having problems, either falling asleep, which is what we call sleep onset insomnia,

00:43:38.540 or you can fall asleep, but you can't stay asleep, which is what we call sleep maintenance insomnia,

00:43:45.420 you want to build up as much sleep pressure, as much sleepiness as you possibly can during the day.

00:43:52.900 If you are struggling with your sleep at night, do not nap during the day. And the pressure cooker

00:43:58.160 analogy is beautiful. Keep building up all of that healthy sleepiness pressure, because when you nap,

00:44:04.320 it's like having the valve on the cooker open up and you just, you just release some of that healthy

00:44:09.940 sleepiness. And now when it comes time to go to bed, you're not going to feel as sleepy anymore.

00:44:15.220 However, on the flip side, if you are not struggling with your sleep and you can nap regularly during the

00:44:22.620 day, the advice is naps can be just fine. Because in fact, if you take a step back from an evolutionary

00:44:29.440 perspective and you study hunter gatherer tribes whose way of life hasn't changed for thousands of

00:44:34.720 years, they don't necessarily sleep the way that we do in modernity. In fact, particularly during the

00:44:40.700 summer months, they will typically have an afternoon nap right in the time zone that you just described.

00:44:46.780 And this is the very much the Mediterranean siesta like behavior. And in fact, if I stick an electrode on

00:44:54.080 both of our heads throughout the day, and I monitor our physiological brainwave activity,

00:44:59.360 it'll stick much better to my head, by the way, than you.

00:45:02.900 Well, yeah, right now, especially because I've got this terrible COVID hairdo, which I look like I

00:45:08.340 should be out of Buck Rogers and anybody who remembers that television show. But anyway,

00:45:13.260 what we will see is that somewhere between about 2 to 4 p.m., both you and I will have this kind of

00:45:19.400 drop in our physiological alertness, in our physiological level of brain activity. In other

00:45:24.940 words, as if as a species, we're almost pre-programmed to have this enforced dip in our

00:45:32.780 alertness. And so many people see this, you know, in the afternoon meetings around the boardroom table

00:45:38.260 or wherever, you sort of get these ugly head nods that start to happen. It's not people listening to

00:45:43.180 good music. It's just that people have this sort of, they're falling asleep, they're falling prey to

00:45:49.060 this, what seems to be a genetically hardwired pre-programmed drop in our alertness, as if maybe

00:45:55.300 we should be what's called biphasically sleeping as a species at times during the year, rather than

00:46:01.900 monophasically sleeping, which is how we do in most First World nations. In other words, one single bout of

00:46:07.820 sleep at night versus two bouts of sleep, which is how those hunter-gatherer tribes sleep, especially

00:46:14.300 during the summer. And so Matt, would they sleep long enough in that two to four window that they

00:46:20.100 would get a full 90 minutes, say, and get through a full cycle? And then if so, did that mean when

00:46:26.360 they did their nighttime sleep, presumably they would stay up later and get maybe six hours in the

00:46:32.380 evening instead of, you know, because people always talk about how well hunter-gatherer studies have

00:46:36.400 always suggested that, you know, seven and a half to nine is the species required amount of sleep on

00:46:41.720 average, but you're saying it was potentially broken into two chunks. Was that afternoon daytime chunk

00:46:48.020 or daylight chunk, call it, about 90 minutes? No, it wasn't. It was actually typically shorter than that

00:46:54.980 on that basis. But you're right, they typically are not sleeping. What we currently recommend for

00:47:01.400 monophasic sleep, which is the average adult should get somewhere between seven to nine hours. That's

00:47:07.520 the recommended range that we all provide. But what they would typically do is they would maybe sleep

00:47:14.220 just six, six and a half hours at night, and then they would make the rest up and they would get into

00:47:20.660 that exact same sort of territory by way of the nap. So they would take it in these two chunks. Now,

00:47:27.680 I should note, this is very different to something else that's been described in the literature,

00:47:31.880 which is first sleep and second sleep. That activity does seem to have occurred during our

00:47:39.480 historical past. It seemed to have emerged in the sort of Dickensian era. That was different though.

00:47:46.140 That was where people would sleep for the first four hours. Then they would wake up in the middle of the

00:47:50.240 night. They would, you know, write, they would drink, they would play music, they would make love,

00:47:54.980 and then they would go back for another four hours of sleep. Did that happen? Yes, it seems to have

00:48:00.680 based on historical writings. But is that the way our physiology and our circadian rhythms are designed?

00:48:07.600 No, it doesn't seem to be. There's usually one study that's cited that suggests maybe we should do

00:48:13.140 that. But overall, the physiology that we know of for human beings doesn't seem to suggest that that

00:48:18.600 was more sociologically driven rather than biologically driven. Biologically, we may be

00:48:25.760 biphasic, but very differently, according to this hunter-gatherer sort of tribe hypothesis. By the way,

00:48:31.840 the other thing that's interesting in those hunter-gatherers, and it comes on to what I think

00:48:35.520 we described before, which is this concept of midnight. Most of us don't think of what the term means,

00:48:42.040 but in those individuals, it means what the word states, which is it's the middle of the night for

00:48:49.300 them, midnight, because they usually go to bed maybe two hours after sundown, and they're asleep,

00:48:56.720 you know, by let's say 9 p.m. in the evening or 8.30, and then they're awake, you know, just a little

00:49:03.440 bit before dawn. In fact, what's interesting, and maybe we'll get onto this in later discussions or we

00:49:09.080 won't, but what seems to wake them up is not necessarily daylight. It's the change in temperature

00:49:15.380 because there's a rise in temperature that seems to happen before daylight starts to break. And it

00:49:23.620 seems to be, it's the temperature change that they are much more buckled to in terms of regulation of

00:49:30.140 their sleep-wake rhythm. And so the way in which the structure of their sleep biphasic is different to

00:49:37.220 ours in modernity and the timing of their sleep is different to some of our timing. You know,

00:49:44.060 for many people, midnight is the time that you think, well, I should just check Facebook one last

00:49:48.340 time or, you know, send my last text. That's what midnight means. But normally for a couple of

00:49:55.060 thousand years or hundreds of thousands of years, it probably meant that was the middle of your solar

00:50:00.460 cycle and it was the middle of your sleep cycle. I'm glad I'm closer to our ancestors. If I could

00:50:08.200 go to bed at eight o'clock every night and wake up at four, that is a perfect night of sleep for me.

00:50:17.940 Matt, and on previous episodes, obviously we went into some pretty good depth on tricks, tips,

00:50:24.080 et cetera. Inside our practice, we have a whole sleep hygiene protocol and we sort of run patients

00:50:32.100 through it relatively early, especially if they're having any sleep issues. But do you mind just sort

00:50:37.300 of going through where you are now and how you think about this? And again, I'll caveat this by saying

00:50:42.720 you're not a sleep physician. So it is not your practice to be out there treating anyone individual

00:50:48.960 with respect to their sleep. That's right. But also you're, you're infinitely more qualified than

00:50:53.620 virtually anybody to help people start to think through what the parameters are that factor into

00:50:59.460 sleep. And that's the way we kind of explain it, which is look, here are these five or six levers of

00:51:04.020 sleep and here's how you could move each of them in your control. But, but I kind of want to hear

00:51:08.900 what, how you think of it. Yeah. So I think in our past episodes, we've gone through sort of the

00:51:14.320 fine five main sort of sleep hygiene tips and I'll just quickly go through them here because

00:51:20.440 we've dealt with them before, which is regularity, going to bed at the same time, waking up at the

00:51:25.080 same time, getting lots of darkness at night because we are a dark deprived society. And I actually think

00:51:32.540 I've done a bad job of describing to the public, the importance of the opposite, which is making sure

00:51:37.340 you get daylight during the first half of the day. I think that's just as important. Then temperature,

00:51:43.260 we've spoken about that a little bit. You need to get cool to get to sleep. And it's the reason that

00:51:48.700 you will always find it easier to fall asleep in a room that's too cold than too hot.

00:51:53.220 You shouldn't stay in bed awake. That trains your brain to be triggered by your bed and force you

00:52:00.160 awake because you have a learned association. So if you've been awake for 20 minutes, then get up,

00:52:06.900 go and do something else and only come back to bed when you're sleepy is the general rule.

00:52:11.260 And then finally, trying to avoid alcohol and caffeine in the afternoon and for alcohol in

00:52:17.660 the evenings, as we've said. So those are the sort of typical tips. But I think if I were to add a few

00:52:24.100 others, the other one that's absolutely critical that I probably haven't espoused enough is a wind

00:52:30.300 down routine. Because many people in society expect sleep to be like a light switch, that we should just

00:52:37.680 jump into bed and we should just turn off the light and the brain should do something similar and go

00:52:43.180 straight into sleep. Sleep as a physiological process, if you study it, it's just not like that.

00:52:49.620 Sleep is much more like trying to land a plane. It takes time to gradually descend down onto that

00:52:57.880 hard foundation of this thing that we call a stable night of sleep. So give yourself some wind down

00:53:04.200 opportunity time. Build it into your routine. For some people, it's 15 minutes. Others, it's 30

00:53:09.760 minutes. Light stretches, meditation, putting all of your phones and your gadgets away, staying clear

00:53:16.300 of any inbound in the last 30 minutes. Whatever it takes, set it up and then maintain it. Because

00:53:22.480 if you have kids, you'll know all about this. You have a routine for the kids and you've got to try

00:53:28.520 and stick to it. If you break the routine, bad things usually happen with sleep. We're the same

00:53:33.060 as adults. There's no difference. So I think that's the first thing I would say. The second

00:53:38.780 probably tweak is if you are struggling with sleep, remove all clock faces from your bedroom.

00:53:48.580 It's not going to help you to know that it's now 2.35 a.m. in the morning and you've still not been

00:53:55.160 able to fall asleep. It's only going to trigger more anxiety. And there's been a nice study here

00:54:00.340 from UC Berkeley, not from my center, but from another sleep researcher, Alison Harvey, who looked

00:54:05.300 at this in people who are poor sleepers with insomnia. Removing clock faces can certainly help.

00:54:11.020 The next thing I would say is that try to keep, of course, all of your technology outside of the

00:54:16.600 bedroom. And if you can, don't make it the first thing that you check in the morning. Because for most of

00:54:23.840 us, the first thing that we do when we wake up is that we swipe right and this flood of anxiety just

00:54:29.240 washes onto us like a tsunami. And that's problematic, not just because it's a bad way to start your day,

00:54:35.660 but because you train your brain in this Pavlovian way that every morning, as you're tucking yourself

00:54:42.380 into bed at night, every morning, what's coming to you when you wake up is this jag of what we call

00:54:48.940 anticipatory anxiety. And it lightens your sleep throughout the night because of that expectation.

00:54:56.120 So try to avoid that. If you absolutely have to, and again, trying not to be puritanical, take your phone

00:55:02.840 into the bedroom. One of the other problems is that it causes what we call sleep procrastination, which is that

00:55:08.560 you're sitting there in bed, you've got your device and you think, well, I'll just check Amazon and order that

00:55:12.880 thing. I'll just check Facebook and I'll just, I'll send that last email. And you look up and now it's 40

00:55:18.100 minutes later. The rule of thumb that a friend, a colleague of mine, Michael Gradner said, I love

00:55:24.060 this. If you're going to have your phone in your bedroom, the rule is that you can only use it if

00:55:29.580 you're standing up. And after standing up for about five or 10 minutes of phone use, you just think,

00:55:35.180 I just want to sit down. I just want to get into bed. And at that point, the rule is you've got to put

00:55:40.260 your phone away. So those would be sort of three additional things that I would advise that can really

00:55:45.620 help. I like that a lot. I would actually add just from a personal standpoint, I've maybe three

00:55:51.760 months ago instituted a little policy for myself that I've really enjoyed, which is not looking at

00:55:57.400 my phone for an hour when I wake up. Luckily, I don't sleep with my phone in my room, so that's not

00:56:04.140 an issue. But it used to certainly be the first thing I'd go and grab when I got up. And if I get up

00:56:11.600 five, I won't look at it till usually after 6am. And that's interesting. I didn't realize that the

00:56:18.480 effect that that could have on my brain as I'm coming into consciousness, knowing that I'm not

00:56:23.800 going to be flooded with information, especially the type of information I don't like, which is

00:56:28.300 generally all the information on my phone. Yeah, I'll just stick two additional pins in that. The

00:56:33.100 first is, I think everyone has had this experience in the extreme, which is where you know you've got to

00:56:39.280 wake up the next day for an interview, or you've got to wake up for a flight that you have to catch.

00:56:44.640 You know, for a fact that firstly, your sleep is going to be shallow, it's not going to be

00:56:48.380 particularly deep. And secondly, you almost wake up two minutes before the alarm because you're that

00:56:53.620 on edge. Well, imagine a diluted version of that. But every single day, that's what bringing your phone

00:56:59.800 into the bedroom and opening it up first thing is all about. The second thing I would say is you're

00:57:06.020 right. And set manageable goals. I really enjoy the work of a guy called BJ Fogg, who's a researcher

00:57:12.300 at Stanford who looks at behavioral change. And it's all about incremental. So if you're trying

00:57:17.000 to get someone to floss their teeth for the first time for dental hygiene, don't say, okay, here's how

00:57:22.620 you floss. You need to floss before you go to bed. You say, all you're allowed to do for the first

00:57:27.460 week is floss your front two teeth and you cannot do any more. That's it. And then we say, then's the

00:57:35.320 next, then add two more teeth for the next week. And then two more. The same with sleep. If you are

00:57:41.480 accustomed to doing this with your phone, which is so understandable for all of the pressures that we

00:57:46.300 understand from society and social media, start by saying, I'm going to give myself five minutes.

00:57:52.380 I'm going to firstly, not check my phone. I'm just going to wake up, brush my teeth and make whatever

00:57:57.120 drink that I have in the morning. And when I sit down, that's when I am gifted the opportunity to

00:58:03.100 look at my phone and then try to push it to 10 minutes and then try to see if you can get changed,

00:58:09.240 have your shower, wash yourself up, whatever you do in the morning, and only then open up your phone

00:58:13.900 and keep pushing it longer and longer. Make it a manageable goal. Otherwise don't set yourself up for

00:58:19.240 failure. Do it for success. Yeah. I think the same advice is great for something like meditation,

00:58:24.820 where, you know, for many people saying, Hey, why don't you commit to 20 minutes of meditation a day?

00:58:30.460 I mean, that's, that's almost impossible out of the gate, but if it's, Hey, meditate every day. And if

00:58:35.940 you do a three minute meditation that, you know, you're better off doing three minutes a day than 20

00:58:40.160 minute once a week. Um, I think it's the same sort of idea, which I, which I agree. I think it becomes a lot

00:58:44.820 easier. The last thing I would say is that none of these tips that we've spoken about, which are

00:58:50.220 typically sleep hygiene tips are going to work if you actually have a sleep disorder. So the analogy

00:58:55.500 here, again, from a colleague, if I'm an athletic sports coach and I'm giving you all of these tips

00:59:01.720 for improving your performance, but you've got a broken ankle, none of them are going to make any

00:59:06.580 difference to your performance until we actually get you to a doctor and fix the broken ankle.

00:59:10.720 It's the same with a sleep disorder. If you have, you know, insomnia, or if you have sleep apnea,

00:59:16.920 none of these things that I've been talking about are going to help you. If you suspect that you have

00:59:21.600 either one of those, definitely go and see your doctor, see if you can get some kind of sleep

00:59:26.020 intervention. Okay. Let's shift on to temperature. We have a ton of questions on this, including one of

00:59:38.020 my patients who has specifically asked me to ask you a bunch of questions on this. So I'm looking at

00:59:44.600 all these questions of which there are so many, and I want to start at the top rather than, so I'm

00:59:49.580 going to kind of mix up the order a little bit on these. And this question in particular, I think is

00:59:53.520 a great foray into the discussion. So the question is, did our ancestors get better quality sleep during

01:00:00.120 certain times of the year and, or in certain climates? So for example, Death Valley in the summer,

01:00:06.700 and I don't know how many of our ancestors were spending that much time there, hopefully not too

01:00:09.940 many, but presumably there are hot places, cold places, et cetera. So I think what this question

01:00:16.620 is obviously getting at is there's a general belief that we sleep better when we're colder.

01:00:21.240 There must've been a number of times when our ancestors were either in places that were not

01:00:26.900 cold or in places where at least during a season it was warm. What can we infer or impute about sleep

01:00:32.980 quality and temperature from that? So the best data that we have right now, again,

01:00:36.720 comes back to some of these hunter-gatherer tribes. Some of them live at different latitudes and the

01:00:42.160 best data that we have are folks who are very close to the equator. And at that point you think, well,

01:00:47.040 how is this going to answer the question? Well, temperature variation where they're at is still

01:00:51.300 quite significant from summer to winter. It turns out it's just more about sort of, yes, rainy season

01:00:58.340 and dry season, but the temperature does fluctuate by some degrees too. And you can look at other

01:01:02.640 communities that are a little bit further out, but here's what we find. In the summer, typically,

01:01:07.200 yes, they actually sleep less when it's hotter, which is going against what needs to happen to your

01:01:12.880 core body temperature to get good sleep. It needs to drop and it needs to get cold. During the hotter

01:01:17.620 seasons, they typically sleep less at night. And then they seem to try and do some recovery by

01:01:23.620 doing a short afternoon siesta. But when they switch over to the winter season where it's cooler,

01:01:30.220 it's a little bit darker, but not that much. But it's really the temperature when they get cooler,

01:01:34.920 then they sleep longer at night. And the frequency with which they have daytime naps actually decreases.

01:01:42.280 So I think that's the best evidence that we have right now from just sort of going back to basics,

01:01:48.280 homo sapiens, what was going on in terms of temperature. The seasons give us the experiment,

01:01:53.100 and the data favors coldness for longer sleep.

01:01:57.760 When you now bring that question to a laboratory, where presumably you can take,

01:02:03.360 and someone has done this, I'm sure, where they've taken subjects and basically develop

01:02:07.840 the optimization curve of all things equal but temperature, there must be an optimization.

01:02:14.500 There's probably temperatures at which you reduce latency, so it's easier to get to bed,

01:02:20.180 but maybe temperatures where it's harder to stay asleep. For example, using myself as an example,

01:02:26.580 I actually like to be really cold when I get in bed. And if I am, it might take me a little longer

01:02:33.200 to fall asleep, a minute or two, but it almost guarantees I'll sleep in a more uninterrupted

01:02:39.120 fashion throughout the evening. There are times when I get into bed, and this is, again, not true at home

01:02:44.380 because I can control the temperature in my home. I have more difficulty controlling it here, for

01:02:49.300 example. Like, we're in Bakersfield. It's hot as Hades. The last two nights, and again, it could be

01:02:54.060 the excitement of racing, but I also feel like I've been waking up a little warm, and I don't have my

01:02:58.260 chili pad. I don't have that little cooling pad on my blanket. I've had no issues with latency,

01:03:02.280 but I'm waking up early. So if you run through all the permutations and combinations of this,

01:03:05.740 can one say there is an optimal room temperature or air temperature or skin temperature or something

01:03:13.040 that we should be driving towards? So right now, the data that we have is somewhere around about

01:03:18.340 65 to 67 degrees is optimal for the sleep of most people. Now, there's going to be variability there

01:03:24.720 for sure, and we know this. We can see this in the data too. But it's actually even a little bit more

01:03:30.140 complex than that. And there have been studies that people have done where they almost strap in what

01:03:34.720 looks like a wetsuit, but it's got all of these veins that run throughout them, and we can percolate

01:03:39.160 this water. I think we've spoken a little bit about this before, where you can exquisitely control

01:03:44.280 the temperature, hot or cold, at any part of the body. And I'll summarize the findings as the following

01:03:49.700 in terms of temperature. It's a three-part story. For your extremities, you need to warm up to cool down

01:03:57.760 to fall asleep. Then you need to get cold to stay asleep. And then you need to warm up to

01:04:04.720 warm up to wake up. And so the reason that you may be finding latency easier here, but quality

01:04:14.780 of sleep thereafter worse is because it's counterintuitive. How do I drop your core body

01:04:20.020 temperature? I'm going to tell you I'm going to warm you up. But the reason is because if you take

01:04:24.700 a hot bath or a shower, all of the blood is charmed to the surface of your skin and it radiates the heat

01:04:31.900 out of the core of your body. So in fact, your core body temperature plummets. It's the reason

01:04:36.860 that a hot bath is great, not because you're toasty in bed. It's because your core body temperature is

01:04:41.620 plummeting once you get out. So this is why sometimes having a cold room, but socks on or a

01:04:47.940 cold room with a hot water bottle at the end of your bed, just to warm the feet, because it's the feet

01:04:53.620 and the hands that need to get a little bit warm to bring the blood because they are the best

01:04:58.640 radiators of heat out of your body. So when we warm the pores of rats, for example, they fall asleep

01:05:06.240 faster because you're charming the heat out of the core of the body. So the answer to the question

01:05:11.440 really is a little bit more complex. Keep the room cool, warm yourself up a little bit inside of bed

01:05:17.820 to radiate that heat out and get you to sleep quicker. That will make the latency. You fall asleep

01:05:23.160 faster. In other words, then the ambient temperature will keep your body cold throughout that middle

01:05:29.960 section and later section of sleep. And then if you have a sort of a smart thermostat, you can rise

01:05:35.820 that temperature. I would say actually quite late in the game in the, perhaps in the last 20 minutes or

01:05:41.560 the last 15 minutes. And that will try to rocket your temperature out and bring you, you will wake up

01:05:47.720 easier and feel less groggy if that temperature is higher. Now it's hard because the ambient may

01:05:54.680 not necessarily change much of what's going on under the covers, but it's the reason that most

01:05:59.760 people, when they wake up, they would like a hot drink, even sometimes in the summer, because the

01:06:04.660 hot drink for the most part, some people are just using caffeine and that's what they think keeps them

01:06:09.240 awake. But some of that benefit of the caffeine is actually not caffeine. It's just the hot drink

01:06:14.380 itself that is helping bring back up the core body temperature that makes you feel more awake.

01:06:19.820 So can we quantify the following? Someone comes to you and they say, Matt, I'm doing all of these

01:06:24.840 things off my checklist, but currently I sleep at a room temperature of 75 degrees. How much better

01:06:31.140 would you predict I would sleep if my room temperature went from 75 to 65?

01:06:36.740 So I think the hard part of this equation, and some people may face this too, if they look at their

01:06:41.520 data from sleep trackers, you're going to be sleeping better. We know this is using population

01:06:47.000 statistics for an individual. So this is always dangerous. And I never want to sort of fall into

01:06:51.640 that fallacy, but let's go with it. On average, people are more likely to sleep considerably better

01:06:56.700 at 65 than 75. Do you say that in terms of duration or stage quality or what metric?

01:07:03.460 So that's where the devil is in the details, because some people will see it in terms of quantity,

01:07:09.120 particularly the quantity of deep sleep. So when we do these studies, that's where you see some of

01:07:13.360 the greatest benefits for the cooling down throughout the night. That's where sort of the

01:07:17.780 thermal gradient can be beneficial. But what's not told is that the largest effect size is not really

01:07:24.520 in quantity, which is minutes, which is what your sleep tracker, your wristwatch, or your ring will tell

01:07:30.320 you. And you have to be very careful to judge the efficacy of that experimental change on the basis of

01:07:37.480 quantity and minutes. Because if anything, when you look at the data, where you really see the effect

01:07:43.520 is less so in minutes, which is quantity. Instead, it's in quality, which is measured by the electrical

01:07:50.720 brainwave signature. Now, your wristwatch or your ring is not going to be giving you that detail.

01:07:57.540 So if you assume that the drop in temperature has given you a nominal percentage benefit in terms of

01:08:04.240 your deep sleep time, and therefore you don't think it's worthwhile, I think you may want to

01:08:08.960 sort of just second check that logic, because there we're seeing it's qualitative, that's more

01:08:14.660 beneficial. And you as an individual, it's very difficult for you to sense that qualitative change

01:08:19.900 because you're non-conscious, of course. And there's no good trackers out there right now that you can

01:08:24.380 work typically on your periphery that will tell you that metric.

01:08:33.200 So with that said, it's not necessarily that hard of a question because I'm constantly trying to

01:08:37.760 run these calculations about all of my scientific sleep beliefs and think about these three buckets.

01:08:44.080 I think the thing that I've probably changed my mind on most or had a reversal on is the effects of

01:08:50.840 blue light on our sleep. And in fact, in the book, I spoke about a study at the time that had been done

01:08:56.780 out of Harvard, which I still think is valid, where they'd used an iPad where you read on an iPad for an

01:09:02.640 hour versus you read a book under dim light. And they showed that that iPad had this detrimental

01:09:08.500 effect on sleep. It had delayed the release of melatonin. It had caused a reduction in REM sleep.

01:09:14.860 And even when they stopped reading the iPad, it had a blast radius to it where the sleep quality was

01:09:20.740 still bad for a couple of days afterwards. And it was a compelling study and published in a good

01:09:24.580 journal. But over the years, I think there's been some research that's pushed back on that. And

01:09:30.840 there's been some great work from a university in Australia called Flinders University. And Michael

01:09:36.580 Gradazar has done some just great work on this at Flinders. He has changed my mind. I'm less bullish now

01:09:44.540 about the idea that these devices that we use are sleep disruptive because of the blue light.

01:09:50.560 I still think that has an effect. But what I think he's shown in some elegant work is that it's less

01:09:56.260 about the light. It's more about the fact that these devices are just so activating, that these devices

01:10:03.860 are designed to trigger alertness and what we call physiological arousal in the brain. And in other words,

01:10:11.360 what happens when we use these devices, the reason that they're so disruptive to our sleep

01:10:15.620 is less about their blue light. It's more the fact that we are masking our sleepiness with this

01:10:24.160 overriding artificial activation from the devices. In other words, let's say that all of a sudden

01:10:30.280 it's 10 p.m. and you think I'm wide awake. I'm on my computer. I'm working. I've got my phone next to

01:10:36.160 me. I'm checking it. It's pinging. It's dinging. All of a sudden, all of the lights go out. There's a

01:10:41.280 massive electromagnetic pulse that curses across your environment. It knocks out all of the devices.

01:10:47.140 You've got no phone, no iPad, no electricity. I suspect that within about 15 or 20 minutes,

01:10:52.900 you'd start to feel sleepy. And it's not because of the blue light effects. It's the fact that you are,

01:10:59.680 and you were all along sleepy, but these devices, because they're so activating was creating a

01:11:07.680 competing force that hit a mute button on the sleepiness and it activated you. So I've actually

01:11:14.380 down-regulated my belief in the effects of blue light. And I've introduced this new mental framework

01:11:21.540 regarding the effects of the invasion of technology into our evening lives and our bedrooms. And I'm much

01:11:28.400 more now enamored with this idea that they are mentally stimulating rather than blue light

01:11:33.560 emitting. Forgive my ignorance for this question, but has the experiment not been done where you've

01:11:38.780 taken groups of subjects and you've subjected one group to just a blue light? So an actual blue light

01:11:46.680 that's hitting, I forget how many nanometers that is, but the actual- Right, in the shorter that

01:11:51.560 wavelength. Yeah. Yeah. And then you have another group that is just being blasted with red light. And

01:11:56.700 then you have another group that is just being blasted with a regular LED and white light. So

01:12:01.900 you're getting the same intensity of light, but you're moving the wavelength and therefore you're

01:12:07.020 nullifying the stimulatory effect of what's being red or looked at. I mean, to me, that experiment would

01:12:14.540 eloquently demonstrate whether or not blue light per se is the problem. Has that not been done?

01:12:20.040 It has. So people have played around with the wavelength of the light. And what we believed is that it's

01:12:24.820 the cooler blues, the shorter wavelength light that are most detrimental. And the reason that screens

01:12:30.020 were blamed is because they are LED based, which is enriched in the lower visible light spectrum,

01:12:36.460 the shorter wavelength, in other words, the cool blues. And that's why the blame came because it

01:12:41.500 was stamping the brakes on melatonin, especially powerfully. And those studies were done. They were

01:12:46.300 done by Chuck Seisler and Steve Lockley from Harvard years ago. And that led to this sort of belief.

01:12:51.480 And I still think there's good validity in that. And by the way, there was a couple of studies that

01:12:55.760 came out in animals that were now suggesting, at least I think it was in rats or mice. I could be

01:13:01.600 wrong. Or if it was in fruit flies, I apologize, where they actually found the opposite, where they

01:13:05.980 found that the warmer color lights had stronger blocking effects on melatonin. It began this sort of

01:13:11.940 controversy. Had we got it wrong about blue light? And then this work from Flinders University,

01:13:18.080 from Michael was coming online regarding this cognitive component. And it really sort of made

01:13:24.100 me shift my belief system. So yes, those studies have been done and they principally looked at

01:13:29.860 melatonin. I think they studied less a full night of sleep with polysomnography and really asked the

01:13:35.760 downstream consequences. They were just simply saying, how does it affect your melatonin? Which is maybe

01:13:40.840 one step short of saying, how does it then affect as a consequence of that change in melatonin,

01:13:46.300 your subsequent sleep? Without necessarily doing a much more sophisticated study, which I think are

01:13:52.480 now being done, where you do the Coke-Pepsi challenge of same amount of light stimulation.

01:14:00.360 So light is standardized. Right. Light becomes the variable. That's the only independent variable.

01:14:06.740 That's right. And then you start measuring independent variable at polysom and melatonin for

01:14:11.400 what it's worth and do everything. And then you do a second round of studies where light actually

01:14:16.560 becomes the constant stimulus, where you maintain the same light exposure, but in one condition,

01:14:22.600 you're doing something cognitively activating, like building a Facebook account or checking that,

01:14:28.160 versus you're simply just there in front of the blue light, but there's no cognitive stimulation

01:14:34.480 to really do the two by two disambiguation of that. I think those studies are coming,

01:14:39.180 but that's one of the things where I've definitely changed my mind, I think. And I felt compelled to

01:14:46.060 now speak more about that and less about the blue light.

01:14:49.120 The last set of clips will shift our focus to look at the effect that caffeine can have on our sleep

01:14:59.160 and the dangers of sleeping pills. If you find yourself enjoying these clips and want more content,

01:15:03.900 we have seven episodes with Matt, including three AMAs. These are great pieces of content to go back to

01:15:09.520 and listen to if you want to scratch this itch a little bit more.

01:15:18.100 The other place where I think I've changed my mind and maybe even some of my behavior

01:15:22.800 is around coffee and caffeine. And the evidence has continued to mount and it's unignorable. And now,

01:15:33.120 again, these are mostly associational epidemiological studies, which both you and I know

01:15:37.980 are problematic for lots of different reasons, but they're so consistent that if you look at coffee

01:15:43.640 drinkers, they reliably de-risk a whole constellation of diseases that you want to avoid.

01:15:52.220 And yes, there is a dose dependency to it where once you get past kind of like three or four cups,

01:15:58.580 then things go in bad directions or the opposite direction at least. But for the most part,

01:16:04.640 there seems to be this set of very clear associations between low to moderate caffeine

01:16:09.920 consumption and de-risking health disease conditions. How on earth does this square with

01:16:16.480 Matt Walker's espousing of caffeine's impact on sleep and the fact that a lack of sleep seems to

01:16:21.940 be associated with many of those same conditions? The go-between here is that caffeine, of course,

01:16:28.100 can disrupt your sleep. So I've kind of modified my beliefs a little bit. I think caffeine consumption

01:16:35.060 is actually not only just fine, but maybe to be encouraged if there is more causal evidence.

01:16:42.780 I think you and Tim Ferriss would speak about this idea that the dose makes the poison.

01:16:48.940 And that is true with caffeine. But I also think there's a second variable here,

01:16:52.940 the dose and the timing make the poison when it comes to caffeine. If you're drinking it later in

01:16:59.220 the day, then I don't think we would see those same health benefits. We would see health detriments

01:17:04.680 and we don't have the data to help to find that. But then I've added a layer of complexity to that

01:17:11.580 after listening to a good friend of mine and a writer here in Berkeley, Michael Pollan,

01:17:16.520 who wrote a book on Audible that you can hear called Caffeine. And it goes into great depths.

01:17:23.080 And we spoke about this. He interviewed me for the book. He believes that the health benefits,

01:17:28.260 which are very hard to deny of caffeine, are not really due to a cup of coffee. It's actually the

01:17:34.860 fact that the coffee bean itself carries with it lots of antioxidants. And in fact, the reason that

01:17:41.280 you get these health benefits is because the antioxidants take a joy ride on the good bus

01:17:47.280 of this thing called caffeine. And his belief is that for Americans, for many Americans who don't

01:17:53.500 get a balanced diet, coffee in the morning may be one of the only primary sources of antioxidant

01:18:00.640 consumption. And that's why you see the health associations. And in fact, I looked at a fantastic

01:18:05.420 review from 2017. And what they found was that in fact, decaffeinated coffee, which carries the same

01:18:12.860 antioxidant load, but without the caffeine has many health benefit associations with it, which then

01:18:20.140 started to make it all a bit more nuanced that perhaps it's more about the antioxidant benefit

01:18:25.360 rather than necessarily the caffeine benefit. But there is certainly an association with coffee

01:18:32.020 that I think makes me more likely to tell people it's fine to be drinking a couple of cups of coffee

01:18:38.580 in the morning. Please do that. In fact, if anything, there seems to be some health benefits.

01:18:43.180 I think it's probably because of the antioxidant benefits, but I've changed my mind there too.

01:18:47.660 I think I've become more relaxed. And in fact, I've now started to drink decaffeinated coffee in the

01:18:52.280 mornings. And is the reason you're not drinking caffeinated coffee because it just activates you too

01:18:58.160 much or because you still fear it will, and because you fear it will impact your sleep negatively?

01:19:03.420 Yeah, it's because I still fear that it impacts my sleep negatively. There was a study by

01:19:06.840 a good colleague of mine at the University of Surrey in England called Dirk Jan Dyke, published many years

01:19:11.340 ago. And they were actually dosing people with caffeine at seven o'clock in the morning, and they

01:19:16.080 could still pick up in the signal of subsequent deep electrical sleep that following night, a reduction in

01:19:22.760 quality of that deep sleep. So I think, again, it depends on who you are. There are genetic differences

01:19:29.580 in how quickly people metabolize caffeine. And I think I'm someone who may be on the moderate end of

01:19:36.880 the sensitivity spectrum. So I typically stay away from it. But other people, I think, probably don't

01:19:43.200 have that same sensitivity in morning coffee consumption. Caffeine is fine.

01:19:47.760 Well, thank you, Orrin Hatch, for the supplement industry. We owe you a debt of gratitude. And I

01:19:58.740 hope you can hear the sarcasm in my voice. I think most people now are wise to it. And we certainly

01:20:04.400 spoke about it at length in the original episodes about the real downside of things like Ambien,

01:20:10.420 Lunesta, these drugs. In fact, very recently, I just saw something in the news that tried to tally

01:20:15.580 up the number of deaths that could actually be attributed to these things. So I mean, I feel

01:20:20.080 very comfortable telling patients that I would rather you stick your genitals in a grinder than

01:20:28.400 you take Ambien or Lunesta. There's always the point in taping a podcast with Peace Retia where it

01:20:35.340 just comes to one of these wonderful crescendos. The things that I think about, but I have no bravery to

01:20:41.420 say, and he just comes out and says them. And this is part of the reason I adore him as a friendly

01:20:46.480 colleague. Yeah, I really hate these drugs. I really hate them. By full disclosure, I still

01:20:50.260 prescribe them on occasion to patients who really insist on having them as a safety net. I would

01:20:54.600 not let any patient have those. And I can monitor by prescription. There's no patient I'm going to let

01:20:58.880 take those drugs every night. And maybe if they needed a couple of nights a month as they're traveling

01:21:03.700 and such, we work really hard to get them off it. But let's talk about sort of the softer

01:21:08.280 things that people often rely on consistently for sleep aids. What about things like Benadryl or

01:21:13.360 Advil PM? I get a lot of questions about that here. I don't think we would argue that those are good

01:21:17.940 for sleep. I think that maybe we could frame the question as how bad are they for sleep?

01:21:22.240 Yeah. So firstly, to come back to Ambien and sort of its collection, Lunesta, all of those classic,

01:21:27.820 what we call the sedative hypnotics. In fact, you're right. I think it was nine days ago from the point

01:21:33.220 that we're speaking right now. The FDA updated its mortality risk warnings regarding those sleeping

01:21:40.540 pills because of this increased risk of death, both acutely for a number of reasons, but also

01:21:46.760 this data just chronically in terms of elevated risk of far greater. Right. Cancer. We also see in part,

01:21:54.120 I think it's probably because of a weakening of the immune system. And I think we spoke about this

01:21:58.360 before. The irony is that sleep is incredibly powerful in boosting the whole collection of

01:22:04.660 weaponry in your immune system. Yet when you sleep and sleep longer with those sleeping pills,

01:22:11.600 you would imagine your immune system gets even better. The opposite seems to be true. It gets worse.

01:22:17.260 And the reason we know this is because there's higher rates of infection in those patients who are

01:22:21.500 taking sleeping pills scales with the degree of use and dosage. So I would say trying to use those as

01:22:29.340 a very last resort. Now, there are some patients for whom alternatives don't seem to work. And for a

01:22:36.560 short period of time, that seems to be recommended right now by the medical community. But I should also

01:22:42.200 note that in 2016, the American College of Physicians made a landmark recommendation that they said,

01:22:47.800 based on the health risks and the concerns, together with the nominal benefit of those sleeping pills

01:22:53.380 above and beyond placebo, sleeping pills must no longer be the first line recommendation for

01:22:59.820 insomnia. It has to be something else called cognitive behavioral therapy for insomnia or CBTI,

01:23:05.200 which we can come back to in a second. Which I've had three patients go through formal CBTI

01:23:10.200 with great success. It's a non-pharmacological, it's a psychological method. You work with a therapist

01:23:16.180 and they try to understand where your sleep problems are at and create a bespoke solution

01:23:22.000 for you, the individual. So there's lots of tools in the CBTI box that we can use to try and help people

01:23:29.320 sleep better. And because everyone who has sleep problems is usually a little different from one

01:23:35.000 person to the next, you have to create a more Savile Row tailored suit for that person in terms of that

01:23:40.360 sleep prescription, quote unquote. But it's just as efficacious as sleeping pills in the short term.

01:23:46.680 But what's better is that when you start working with your therapist, those benefits can last. Now, I think

01:23:52.500 the last report was maybe somewhere between up to five years that you can maintain that benefit, unlike

01:23:58.220 sleeping pills, where when you stop them, you not only go back to the bad sleep that you had, it's usually

01:24:03.860 even worse. It's called sleep rebound insomnia. How do you recommend people find good CBTI therapists?

01:24:10.180 Because like all things therapy-wise, the practitioner matters. Now, I've been very fortunate

01:24:14.860 because we work with this amazing sleep doc named Vic Jane in Chicago and wherever my patients are,

01:24:20.600 if it's San Francisco, New York, he knows the best therapists and he just makes that introduction,

01:24:25.280 plugs us directly in. But if you're listening to this and you're thinking, I live in St. Louis and boy,

01:24:30.340 would I really benefit from this? How can a person listening figure out, there's a just trial and

01:24:36.820 error. You just have to go through people until you find someone who's really clicking with you.

01:24:40.720 So one of the things that we can do, maybe in post in the show notes, there is a website that

01:24:44.940 comes out of the American Academy of Sleep Medicine. And there is one page, it's not that easy

01:24:50.820 to find, but I know the link, so I'll send it out. And you go to that link and you insert your zip

01:24:56.540 code into this website. So this is of course, just for people in America and it will return

01:25:02.860 the closest certified centers by the American Academy of Sleep Medicine for sleep disorders,

01:25:10.480 including CBTI. And you can give it a radius and you can give it a distance. Tell me where it's close

01:25:16.420 and they will give you the sleep centers to contact, contact them and you can go from there.

01:25:21.360 And what should you look for in terms of, because we know that all doctors are not created equal,

01:25:26.600 all mechanics are not created equal, all lawyers are not created equal. How does a person evaluate

01:25:31.940 their own individual or is it simply through the results?

01:25:35.800 I mean, right now it's going to be in part trial and error. And I would say have a conversation with

01:25:41.940 two or three potential CBTI therapists and just try them on for size, see how they work.

01:25:48.580 If you can get any referrals right now, sometimes you can even go onto places like Yelp or other

01:25:53.860 places where you can get some reviews too. Some people, if they're motivated to write, it's usually

01:25:59.120 because they had a bad experience. So keep that bias in mind. But I would say if you can get a

01:26:03.940 referral from a friend or a colleague, that's a fantastic way to go too. And then speak to these

01:26:09.780 people and ask them about their success rates and ask them also, where have you found problems with

01:26:15.820 your patients? Which patients have you typically had the hardest difficulty with in terms of their

01:26:21.340 profile of sleep problems? And if they sound like you, then maybe you want to look elsewhere as well.

01:26:27.520 But CBTI over sleeping pills for sure. In terms of things like Tylenol PM or...

01:26:36.100 Benadryl is, yeah.

01:26:37.240 Benadryl is typically used. There is a little bit of evidence that Benadryl-induced sleep also has some of

01:26:44.560 the risks associated with it that sleeping pills have. It's less potent in terms of that bad

01:26:52.340 consequence and outcome to sleep. But the bad consequence and outcome remains statistically

01:26:58.120 significant in those reports. So I would shy away from things like Benadryl as well. Tylenol PM,

01:27:05.560 I just don't think there's good enough data yet to suggest that it's either good or bad.

01:27:09.840 And what about low doses or intermittent use of benzodiazepines, either short-acting ones like

01:27:16.560 Ativan or longer-acting ones, Xanax or longer-acting ones like Valium? I talk about this in my jet lag

01:27:22.540 protocol when I'm doing heroic bursts of jet lag, 12-hour time zone difference, and I have to put

01:27:29.140 myself to sleep. We talked about the entire routine around exercise and caffeine and going to sleep

01:27:34.260 immediately getting on the plane. And I use phosphatidylserine, and I use the Kirk Parsley

01:27:38.840 stuff. And I'll also use Valium to just make sure I am out. And what are your thoughts on the short-term

01:27:45.280 use of benzos, again, paired with these other agents around jet lag? I don't think anyone's

01:27:51.180 really advocating they'd be used in any ongoing manner either.

01:27:53.820 Certainly not, yeah. Infrequent use, I suppose it depends on how infrequent. In one of the studies

01:27:59.580 by a guy called Dan Kripke, who is actually emeritus here in San Diego, he just looked at not

01:28:05.240 only whether use of sleeping pills was detrimental to mortality, he looked at the frequency of how

01:28:13.320 often you were taking those. And what he was finding is that even anywhere between three to 18 pills

01:28:19.700 per year carried a statistically significant increase in mortality risk.

01:28:24.920 And did he put benzos in the same category as the Ativan Lunestas?

01:28:30.420 He did, yeah. So he sort of has broken some of that stuff down and broken it out too. I would say,

01:28:36.080 in truth, see how far you can really get with all of the other kaleidoscope of possibilities of sleep

01:28:42.380 enhancing possibilities that we've discussed. And if those fail, then I think you can think about

01:28:48.540 less resources. But those drugs typically just are not producing natural sleep. So I would

01:28:54.800 think of those medications like that box on the wall that says, break glass in terms of emergency.

01:29:00.720 If you're in that situation and you're really struggling, then it's possible that that's the

01:29:05.600 time to break the glass. But those shattered shards can sometimes still-

01:29:09.240 They can still cut you.

01:29:09.880 What about GHB or Zyrem as a precursor? This is a drug that is incredibly potent in patients with

01:29:17.540 narcolepsy. Zyrem is available by prescription. Of course, unless you have narcolepsy,

01:29:22.180 you're going to pay an unbelievable amount. It's one of the funniest sort of

01:29:26.480 economic incentives imaginable. But several listeners have asked, and several of my patients

01:29:33.620 actually have asked about, does Zyrem actually produce appropriate sleep staging? What's the

01:29:39.560 data on that?

01:29:40.160 Right. So the data, if you look at it, almost looks like Zyrem is a great drug or GHB is a

01:29:45.760 great drug for increasing the amount of deep sleep that you have, mostly because it puts your brain

01:29:51.740 into a more sort of sedated, slow rhythm, which a sleep technician, if they didn't know that you

01:29:57.860 were on Zyrem, would look at it and say, that looks not dissimilar to deep, slow wave sleep. So I'm

01:30:02.820 going to score it as I'm sort of scoring these eight hour sleep records. I'm going to score it as deep

01:30:07.920 sleep. So overall, in terms of total amount of sleep, GHB or Zyrem does seem to actually increase

01:30:15.080 the amount of slow wave sleep time that is scored by a technician. And I'm being very technical in my

01:30:21.940 language because I want to be precise in this regard. However, if you look at the electrical

01:30:27.900 signature of that sleep, which is now independent. So when a sleep technician scores a trace,

01:30:33.920 they have a set of criteria that they use to define which stage of sleep each 30 second epoch

01:30:40.080 of time, each 30 second window of time there is throughout that eight hour period. And they scroll

01:30:45.700 through a 30 second page by 30 seconds, and they score each of those. They add them all up. That's

01:30:51.200 what gives your sleep profile and sleep score. So using the criteria that we've had now for about 60 or

01:30:56.920 70 years, they will score more of your sleep as being quote unquote, slow wave sleep when you are

01:31:04.000 on GHB, because it seems to produce what looks like slow brainwave activity. And by that criteria,

01:31:11.460 they have to score it as such. But if you unbuckle yourself from this kind of standard sleep scoring

01:31:18.860 criteria and a human, and you just let an algorithm process the electrical signature of that sleep,

01:31:24.340 it now does not look like naturalistic sleep. And in fact, if there's anything that we've seen that

01:31:30.520 Xyrem seems to be detrimental to, it's actually these things called sleep spindles. Now sleep spindles

01:31:38.080 are these short synchronous bursts of electrical activity that happen during non-REM sleep. They last

01:31:43.860 for about a minute or a minute and a half. And we know from the work that we've done and other people

01:31:49.440 have done, they are critical for things like learning, memory, and brain plasticity. And what

01:31:55.520 we found is that when you take GHB or Xyrem, the amount of sleep spindle activity is decreased often.

01:32:03.620 This shows up sort of at the end of, as you're transitioning from theta to delta, does this

01:32:08.680 typically occur?

01:32:09.500 Actually, what happens is usually sleep spindles at the end of a deep slow wave. So you've got all of

01:32:16.500 these slow waves that happen during deep non-REM sleep. And typically what happens is that sort of

01:32:22.220 once you've hit the peak of that slow wave, you will often have a little bit of a spindle burst. And

01:32:28.680 in fact, those two things couple, it's called phase amplitude coupling. So at the peak of the deep

01:32:35.080 slow wave on its awesome rise up, that's the burst.

01:32:38.700 That's when you get the burst additionally of the sleep spindle. So if I could convert it to a sound,

01:32:43.700 which we've done, you would get these slow waves, which would sort of sound like

01:32:46.820 and then often riding on top of those slow waves, you'll have a sleep spindle. So you'll sort of have

01:32:55.860 like, and that is the sleep spindle. It's this burst of faster frequency activity. And the coupling of

01:33:07.060 those two seems to be critical in terms of things like long-term memory transfer, shifting memories from

01:33:12.520 short-term to long-term. So you protect them and make them safe. Those spindles also seem to have

01:33:18.340 a role in terms of triggering the strengthening of connections between brain cells, something that

01:33:24.340 we call brain plasticity or long-term potentiation within the brain. And when you are blocking those

01:33:30.700 sleep spindles, the idea would be that you're preventing typical memory and brain plasticity events

01:33:37.300 that occur. So once again, you can see that. So it's kind of a lesser of two evils. It's you

01:33:43.160 take a patient who's got narcolepsy. If the alternative is they're constantly falling asleep at the point

01:33:48.960 where they can't function normally, well, maybe we have to give up something. But again, what I'm

01:33:53.980 hearing you say is if you're an individual whose sleep is not fully optimized, assuming you can afford

01:33:59.880 Xyrem, which pretty much no human being can afford it, that's just not the solution either. We don't have

01:34:05.840 deep sleep in a pill. That's right. Your analogy is a good one. No one would say chemotherapy is good

01:34:10.960 for a healthy individual, but when you're suffering from cancer, it's the less of two evils. The same

01:34:15.660 is true in narcolepsy. Yes, you sort of the cost reward equation that is in the favor of taking the

01:34:21.120 medication. Thank you for listening to this week's episode of The Drive. If you're interested in diving

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The Peter Attia Drive - September 05, 2022

#221 ‒ Understanding sleep and how to improve it

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