[0:00] Welcome to Huberman Lab Essentials,
[0:02] where we revisit past episodes for the
[0:04] most potent and actionable science-based
[0:06] tools for mental health, physical
[0:08] health, and performance.
[0:11] And now, my discussion with Dr. Matt
[0:14] Walker. Let's start off very basic. What
[0:16] is sleep? Sleep is probably the single
[0:21] most effective thing you can do to reset
[0:23] your brain and body health. Sleep as a
[0:25] process though is an incredibly complex
[0:29] physiological ballet. Sleep is broadly
[0:31] separated into these two main types. And
[0:34] we've got non-rapid eye movement sleep
[0:36] on the one hand and then we've got rapid
[0:38] eye movement sleep on the other. When
[0:40] you go into REM sleep, you are
[0:42] completely paralyzed. You are locked
[0:45] into a physical incarceration of your
[0:49] own body. Amazing. The brain paralyzes
[0:52] the body so that the mind can dream
[0:54] safely because think about how quickly
[0:57] we would have all been popped out of the
[0:58] gene pool. You know, if I think I'm, you
[1:01] know, one of the best sky divers who can
[1:03] just simply fly and I get up on my
[1:06] apartment window and I leap out, you're
[1:09] done. You're done. Now, of course, the
[1:11] involuntary muscles thankfully aren't um
[1:14] paralyzed. So, you keep breathing, your
[1:15] heart keeps beating. You go through
[1:17] these bizarre what we call autonomic
[1:20] storms. There are only two voluntary
[1:23] muscle groups that are spurred from the
[1:25] paralysis. Bizarre. One, your extra
[1:29] ocular muscles. Because if they were
[1:31] paralyzed, you wouldn't be able to have
[1:33] rapid eye movements. And the other that
[1:36] we later discovered was the inner ear
[1:38] muscle. Some people have argued that the
[1:40] reason the eyeballs are spurred from the
[1:42] paralysis is because if your eyeballs
[1:44] are left for long periods of time
[1:46] inactive, you may get things such as
[1:48] oxygen sort of issues in the um aquous
[1:52] or vitrius humor and so the eyeballs
[1:55] have to keep the drain systems of the
[1:57] anterior eye are made require movement
[1:59] that exactly people with glaucoma have
[2:01] deficits in in drainage through the
[2:03] anterior chamber. So maybe take me
[2:05] through the arc of a night. When I first
[2:07] fall asleep, I'll go into the light
[2:09] stages of nonREM sleep, stages one and
[2:11] two of nonREM, and then I'll start to
[2:14] descend down into the deeper stages of
[2:16] nonREM sleep. So, after about maybe 20
[2:18] minutes, I'm starting to head down into
[2:20] stage three nonREM and then into stage 4
[2:24] nonREM sleep. And as I'm starting to
[2:27] fall asleep, as I've cast off from the,
[2:30] uh, usually with me murky waters of
[2:32] wakefulness, um, and I'm in the shallows
[2:34] of sleep stages 1 and two, my heart rate
[2:36] starts to drop a little bit and then my
[2:39] brain wave pattern activity starts to
[2:42] slow down. Normally, when I'm awake,
[2:44] it's going up and down maybe 20, 30, 40,
[2:47] 50 times a second. Um, as I'm going into
[2:51] light non-REM sleep, it will slow down
[2:53] to maybe 15, 20, and then really starts
[2:57] to slow down down to about sort of 10 or
[2:59] eight cycles per second. Eight cycle or
[3:01] waves per second.
[3:04] Then, as I'm starting to move into um
[3:07] stages three and four nonREM sleep,
[3:09] several remarkable things happen. All of
[3:12] a sudden, my heart rate really does
[3:14] start to drop. Hundreds of thousands of
[3:16] cells in my cortex all decide to fire
[3:20] together and then they all go silent
[3:23] together and it's this remarkable
[3:26] physiological coordination of the likes
[3:29] that we just don't see at during any
[3:32] other brain state. I will then stay
[3:34] there for about another 20 or 30
[3:36] minutes. So now I'm maybe 60 or 70
[3:39] minutes into my first sleep cycle. And
[3:42] then I'll start to rise back up back up
[3:44] into stage two non-REM sleep. And then
[3:47] after about 80 or so minutes, I'll pop
[3:49] up and I'll have a short REM sleep
[3:51] period. And then back down I go again
[3:54] down into non-REM, up into REM. And you
[3:57] do that reliably repeatedly. And I will
[4:00] be doing that every 90 minutes at least.
[4:03] That's the average for most adults. In
[4:06] the first half of the night, the
[4:08] majority of those 90-minute cycles are
[4:11] comprised of lots of deep non-REM sleep.
[4:13] That's when I get my stage three and
[4:15] four of deep nonREM sleep. Once I push
[4:18] through to the second half of the night,
[4:20] now that seesaw balance changes and
[4:23] instead the majority of those 90minute
[4:25] cycles are comprised either of this
[4:27] lighter form of non-REM sleep, stage 2
[4:30] non-REM sleep, and much more and
[4:32] increasingly more rapid eye movement
[4:35] sleep. And who suffers more, those that
[4:37] lack the early phase or those that lack
[4:39] the later phase of the night? Depends on
[4:42] what the outcome measure is. For
[4:44] example, during deep non-REM sleep,
[4:46] that's where we get this. It's almost a
[4:47] form of natural blood pressure
[4:49] medication. And so, when I take that
[4:51] away from you, the next day, we're
[4:53] usually going to see autonomic
[4:55] dysfunction. We're usually going to see
[4:57] abnormalities in heart rate, blood
[4:59] pressure. We also know that during deep
[5:01] non-REM sleep that there is a certain
[5:03] control of specific hormones. For
[5:05] example, we know that the insulin
[5:07] regulation of sort of metabolism um
[5:10] meaning how will you look from a
[5:13] regulated blood sugar perspective versus
[5:16] disregulated pre-diabetic look of
[5:19] profile that's where deep sleep seems to
[5:22] matter. If we selectively deprive you of
[5:24] that we can see growth hormone is
[5:27] different actually. So that's that's a
[5:28] beautiful demonstration where growth
[5:30] hormone seems to be more REM sleep
[5:32] dependent and that's why we can come on
[5:34] to the effects of alcohol and there was
[5:36] there's some really impressive
[5:38] frightening data on on alcohol and its
[5:40] disruption of um of sleep but then we
[5:43] also know testosterone you know peak
[5:46] levels of testosterone happen during REM
[5:48] sleep. It's the second half of the
[5:50] night, which is the second half of the
[5:52] night. So, it really just means that the
[5:55] your profile of mental and physical
[5:59] dysfunction will be different under both
[6:02] of those conditions. Which one would you
[6:05] prefer? I would prefer neither of them.
[6:07] And it really depends on what you're
[6:09] trying to optimize for. So, it's it's
[6:12] just so comp. You know, sleep is just so
[6:15] profoundly detrimental to us if you were
[6:18] to take it at face value. You know,
[6:19] you're not finding a mate, you're not
[6:21] reproducing, you're not foraging for
[6:23] food, you're not caring for your young,
[6:25] and worst of all, you're vulnerable to
[6:27] predation. On any one of those grounds,
[6:30] sleep probably should have been selected
[6:32] against, but it wasn't. Sleep has fought
[6:35] its way through heroically, you know,
[6:37] every step along the evolutionary path.
[6:40] And therefore, every sleep stage has
[6:44] also survived as best we can tell. What
[6:47] that means is that those are
[6:49] non-negotiable if mother nature had
[6:51] found a way to even just sort of, you
[6:54] know, thin slice some of that sleep from
[6:57] us. There would have been vast, I'm
[7:00] sure, evolutionary benefits, but it
[7:02] looks as though she hasn't. And I'm
[7:05] usually in favor of her wisdom after 3.6
[7:08] million years. So in this arc of the
[7:10] night uh slowwave sleep predominates uh
[7:12] early in the night and then REM sleep
[7:15] there's a scenario that many people
[7:16] including myself experience on a regular
[7:18] basis which is they go to sleep sleeping
[7:22] just fine 3 4 hours into it they wake up
[7:25] they wake up for whatever reason maybe
[7:27] there was a noise maybe the temperature
[7:28] isn't right we will certainly talk about
[7:30] sleep hygiene etc they get up they go to
[7:33] the restroom they might flip on the
[7:35] lights they might not they go back to
[7:37] sleep Let's say after about 10 15
[7:39] minutes they're able to fall back
[7:41] asleep. How detrimental is that wake up
[7:45] episode or or um event in terms of
[7:50] longevity learning etc. It is perfectly
[7:54] natural and normal particularly as we
[7:56] progress with age. At the end of our REM
[7:59] sleep period of the 90minut cycle almost
[8:03] everybody wakes up and we make a
[8:06] postural movement. we turn over because
[8:09] we've been paralyzed for so long and the
[8:10] body will also like to shift. For the
[8:13] most part, I think we can be more
[8:14] relaxed about that. Where we have to be
[8:17] a bit more attentive though is if you
[8:19] are spending long periods of time not
[8:22] being able to get back to sleep and
[8:24] usually we define that by saying if it's
[8:26] been 20 25 minutes. The other thing is
[8:29] if it's happening very frequently. So
[8:32] even if you're um you know not awake for
[8:35] 25 minute stretches but you're finding
[8:38] yourself waking up and being consciously
[8:40] aware that you've woken up for maybe six
[8:43] seven or eight times throughout the
[8:45] night and your sleep is very what we
[8:47] call fragmented.
[8:50] The great science of sleep in the past 5
[8:52] or 10 years has has been yes quantity is
[8:55] important but quality is just as
[8:59] important and you can't have one without
[9:02] the other in terms of a good beneficial
[9:04] next day outcome. You can't just get 4
[9:08] hours of sleep but brilliant quality of
[9:10] sleep and be unimpaired. nor can you get
[9:13] 8 hours of sleep but have very poor
[9:16] quality of sleep and be unimpaired the
[9:19] next day. I'm a big proponent of people
[9:22] getting uh some sunlight, ideally
[9:24] sunlight, but other forms of bright
[9:26] light in their eyes early in the day and
[9:28] when they want to be awake. Yep.
[9:30] Essentially during the phase of their
[9:31] 24-hour circadian cycle when temperature
[9:34] is rising and then starting to get less
[9:37] light in their eyes as our temperature
[9:40] is going down in ter later in the day
[9:41] and in the evening. I think that's
[9:43] exactly what we recommend right now,
[9:46] which is try to get at least 30 to 40
[9:49] minutes of exposure to some kind of
[9:51] natural daylight. There was some great
[9:53] work recently coming out in the
[9:54] occupational health domain where they
[9:57] moved workers from offices that were
[9:59] just facing walls and, you know, didn't
[10:01] have any exposure to natural daylight.
[10:04] And then they did a time period during
[10:06] that study where they actually were in
[10:08] front of a window and working and they
[10:10] measured their sleep and their sleep
[10:13] time and their sleep efficiency
[10:15] increased quite dramatically. I think
[10:17] the increase in total sleep time was
[10:19] well over 30 minutes and the improvement
[10:21] in sleep efficiency was 5 to 10%. You
[10:24] know, and if you're batting an 80%, you
[10:26] know, sleep efficiency average, we're a
[10:29] bit concerned about that. But add 10% to
[10:32] that and now you're in, you know, a
[10:34] great echelon of healthy sleepers that
[10:36] these portals are the only way to to um
[10:39] convey to the rest of the brain and body
[10:41] about the time of day and wakefulness. I
[10:43] have a number of questions about
[10:44] caffeine. Does the timing in which we
[10:47] ingest caffeine play an important role
[10:50] in whether or not it works for us or
[10:52] against us? The dose and the timing
[10:55] makes the poison. Caffeine has a
[10:58] half-life and it's metabolized. The half
[11:00] life is somewhere between 5 to 6 hours
[11:03] and the quarter life therefore is
[11:05] somewhere between 10 to 12 hours. It's
[11:07] variable. Different people have
[11:09] different um durations of its action.
[11:12] But for the average adult 5 to 6 hours.
[11:15] So let's say that you know I've been
[11:16] awake for 12 hours now and it's you know
[11:20] 8:00 p.m. and I'm feeling a bit tired
[11:22] but I want to push through and I want to
[11:24] keep working for another couple of
[11:26] hours. So I have a cup of coffee. All of
[11:28] a sudden, I was feeling tired, but I
[11:30] don't feel like I've been awake for 12
[11:32] hours anymore. Then after a few hours,
[11:35] and the caffeine is starting to come out
[11:36] of my system. Not only am I hit with the
[11:40] same levels of adenosine that I had
[11:43] before I'd had the cup of coffee several
[11:45] hours ago, it's that plus all of the
[11:48] adenosine that's been building up during
[11:50] the time that the caffeine has been in
[11:53] my system. So, sort of a an avalanche of
[11:55] It is a tsunami wave. Yeah. And I have a
[11:58] caffeine crash. Given um somebody who
[12:00] typically gets into bed around 10:00
[12:02] 10:30 and falls asleep around uh 11
[12:05] 11:30,
[12:07] when would you recommend they halt
[12:10] caffeine intake? And these are not um
[12:12] strict prescriptives, but I think people
[12:14] do benefit from having some uh fairly
[12:16] clear guidelines of what might be might
[12:18] work for them. Would you say cut off
[12:20] caffeine by what time of the day? I
[12:24] would usually say take your typical
[12:25] bedtime and count back 10 hours or 8
[12:28] hours of time. That's the time when you
[12:31] should really stop, you know, using
[12:33] caffeine is the suggestion. And the
[12:36] reason is because for those people who
[12:37] even just keep drinking up until, you
[12:39] know, the into the evening, you're right
[12:42] that they can fall asleep fine, maybe
[12:44] they stay asleep, but the depth of their
[12:46] deep sleep is not as deep anymore. And
[12:49] so there are two consequences. The first
[12:52] is that for me and it can be up to by
[12:54] 30%. And for me to drop your deep sleep
[12:57] by 30%, I'd have to age you by between
[13:00] 10 to 12 years. Or you can just do it
[13:03] every night to yourself with a couple of
[13:04] espressos. The second is that you then
[13:08] wake up the next morning and you think,
[13:11] well, I didn't have problems falling
[13:13] asleep and I didn't have problems
[13:14] staying asleep, but I don't feel
[13:16] particularly restored by my sleep. So
[13:18] now I'm reaching for three or four cups
[13:20] of coffee the next morning rather than
[13:22] just two or three cups of coffee. And so
[13:24] goes this dependency cycle that you then
[13:27] need your uppers to wake you up in the
[13:29] morning. And then sometimes people will
[13:32] use alcohol in the evening to bring them
[13:34] down because they're overly caffeinated
[13:36] and alcohol and we can speak about that
[13:38] too also has very dilitterious impacts
[13:40] on your sleep as well. Caffeine and
[13:42] alcohol represent the uh the kind of two
[13:45] opposite ends of the spectrum. What
[13:46] happens when somebody has a glass, we
[13:50] always hear a glass or two of wine in
[13:51] the evening or a uh a cocktail after
[13:55] dinner? How does that impact their
[13:57] sleep? So alcohol, if we're thinking
[13:59] about classes of drugs, they're in a
[14:01] class of drugs that we call the
[14:03] seditives. It's sedating your cortex.
[14:07] And sedation is not sleep. But when we
[14:10] have a couple of drinks in the evening,
[14:11] when we have a couple of night caps, we
[14:13] mistake sedation for sleep, saying,
[14:15] "Well, I always when I have a like a
[14:18] couple of whisies or a couple of
[14:19] cocktails, it always helps me fall
[14:21] asleep faster." In truth, what's
[14:23] happening is that you're losing
[14:24] consciousness quicker, but you're not
[14:27] necessarily falling naturalistically
[14:30] asleep any quicker. So, that's one of
[14:32] the first sort of things just to keep in
[14:34] mind. The second thing with alcohol is
[14:37] that it fragments your sleep. And we
[14:39] spoke about the quality of your sleep
[14:40] being just as important as the quantity.
[14:44] And alcohol through a variety of
[14:45] mechanisms uh some of which are
[14:48] activation of that autonomic nervous
[14:50] system, that fightor-flight branch of
[14:52] the nervous system. Alcohol will
[14:55] actually have you waking up many more
[14:57] times throughout the night. So your
[14:59] sleep is far less continuous. Now some
[15:02] of those awakenings will be of conscious
[15:05] recollection the next day. you'll just
[15:07] remember waking up. Many of them won't
[15:09] be. And so, but yet your sleep will be
[15:12] littered with these sort of punctured
[15:15] awakenings throughout the night. And
[15:17] again, when you wake up the next
[15:18] morning, you don't feel restored by your
[15:21] sleep. The third part of alcohol in
[15:24] terms of an equation is that it's quite
[15:26] potent at blocking your REM sleep, your
[15:28] rapid eye movement sleep. And REM sleep
[15:31] is critical for a variety of cognitive
[15:33] functions. um some aspects of learning
[15:35] and memory seems to be critical for
[15:37] aspects of emotional and mental health.
[15:39] It's overnight therapy. What we've
[15:42] discovered over the past 20 years here
[15:43] at the sleep center is that there is no
[15:47] major psychiatric disorder that we can
[15:49] find in which sleep is normal. And so I
[15:53] think that firstly told us there is a
[15:54] very intimate association between your
[15:56] emotional mental health and your sleep
[15:59] health. I don't want to be puritanical
[16:01] here. You know, I'm just a scientist and
[16:04] I'm not here to tell anyone how to live.
[16:06] All I'm trying to do is empower people
[16:09] with some of the scientific literature
[16:12] regarding sleep and then you can make
[16:14] whatever informed choices that you want.
[16:17] My job is not to to tell people um a
[16:20] prescription for life. It's just to
[16:21] offer some scientific information. I
[16:23] would like to ask about marijuana. In
[16:26] many places, not all, medical marijuana
[16:28] is approved or is legal. Does marijuana
[16:31] disrupt sleep? THC can
[16:36] seems to speed up the time with which
[16:39] you fall asleep, but again, if you look
[16:41] at the the electrical brain wave
[16:43] signature of your falling asleep with
[16:46] and without that THC, it's not going to
[16:49] be an ideal fit. So, you could argue
[16:51] it's non-natural. It too, but through
[16:53] different mechanisms, seems to block REM
[16:56] sleep. And that's why a lot of people
[16:58] when they're using will tell me look you
[16:59] know I I definitely I was dreaming I
[17:02] don't remember you know many of my
[17:04] dreams and then when they stop using uh
[17:06] THC they'll say I was having you know
[17:09] just crazy crazy dreams and the reason
[17:12] is because there is a rebound mechanism
[17:15] REM sleep is very clever and alcohol is
[17:17] the same way in this sense it's the same
[17:19] homeostatic mechanism some people will
[17:21] tell me look if I have a bit of a wild
[17:23] Friday night with some alcohol you maybe
[17:26] I'll sleep late into the next morning
[17:28] and I'll just have these really intense
[17:30] dreams. So, and I thought I wasn't
[17:33] having any REM sleep. Well, the way it
[17:35] works is that it's during in the middle
[17:37] of the night really um when alcohol
[17:40] blocks your REM sleep. And your brain is
[17:43] smart. It understands how much REM sleep
[17:45] you should have had, how much REM sleep
[17:47] you have not because the alcohol has
[17:49] been in the system. And finally, in
[17:51] those early morning hours when you're
[17:52] getting through to sort of, you know, 6
[17:54] 7 8 a.m., all of a sudden, your brain
[17:57] not only goes back to having the same
[17:59] amount of REM it would have had, it does
[18:01] that. Plus, it tries to get back all of
[18:04] the REM sleep that it's lost. Does it
[18:06] get back all of the REM sleep? No, it
[18:07] doesn't. It never gets back all of the
[18:09] REM sleep, but it tries. And so, you
[18:12] have these really intense periods of REM
[18:14] sleep. Hence, you have really intense,
[18:16] bizarre dreams. And that's what happens
[18:18] also with THC. You build up this
[18:22] pressure for REM sleep, this debt for
[18:24] REM sleep. Will you ever pay it back?
[18:28] Doesn't seem as though you get back
[18:29] everything that you lost, but will you
[18:31] get back some of it? Yes. The brain will
[18:33] start to devour more because it's been
[18:36] starved of REM sleep for so long. So,
[18:39] I'd love to chat for a moment about the
[18:42] kind of grand the original, I should
[18:44] say, that not the granddaddy, but the OG
[18:46] of sleep supplementation, which is
[18:48] melatonin. Yeah. I was always taught,
[18:51] and I'm assuming it's still true, that
[18:52] the only source of melatonin in the
[18:54] brain and body is the pineal gland. Is
[18:56] that still true? Yeah, it seems to be
[18:58] from best that we can tell. I have to
[19:00] imagine we have melatonin receptors in
[19:02] the brain and body. It's correct.
[19:03] Essentially, your brain has a central
[19:06] master 24-hour clock called the supra
[19:08] chaismatic nucleus that keeps internal
[19:12] time. Now, it knows 24-hour time, but it
[19:17] needs to tell the rest of the brain and
[19:19] the body the 24-hour time as well. And
[19:23] one of the ways that it does this is by
[19:26] communicating a chemical signal of
[19:29] 24-hour nus of light and day using this
[19:34] hormone melatonin. And when it is at low
[19:37] levels or it's non-existent, it's
[19:39] communicating the message it's daytime.
[19:42] And for us dional species, it says it's
[19:44] time to be awake. Yet at nighttime when
[19:48] dusk approaches and the brake comes off
[19:49] melatonin and we start to release it,
[19:52] then it signals to the rest of the brain
[19:54] and the body, look, it's dusk and it's
[19:56] nighttime. And for us dial species, it's
[19:59] time to think about sleep. So melatonin
[20:03] essentially tells the brain and the body
[20:05] when it's day and when it's night and
[20:07] with that when it's time to sleep, when
[20:09] it's time to wake, but it doesn't really
[20:11] help with the generation of sleep
[20:13] itself. And this is where we'll come on
[20:14] to what those studies of supplementation
[20:16] have taught us. So it tells the rest of
[20:18] my brain and body it's time to go to
[20:21] sleep. It it perhaps even aids with the
[20:22] transition to sleep, but it's not going
[20:25] to for instance ensure the overall
[20:27] structure of sleep or um it's not the
[20:30] conductor that's guiding the sleep
[20:32] orchestra so to speak throughout the
[20:34] entire night. You know, melatonin is
[20:35] like the starting official at the 100
[20:37] meter race in the Olympics. That's a
[20:39] better analogy. call calls all of the
[20:41] the sleep races to the line and it
[20:44] begins the great sleep race, but it
[20:46] doesn't participate in the race itself.
[20:48] That's a whole different set of brain
[20:50] chemicals and brain and brain regions
[20:53] which then brings us on to perhaps the
[20:56] question of supplementation
[20:59] which is
[21:02] is it helpful for my sleep? Will I sleep
[21:04] longer? Will I sleep better? Sadly, the
[21:07] evidence in healthy adults who are not
[21:10] older age suggests that melatonin is not
[21:13] really particularly helpful as a sleep
[21:15] aid. I think there was a recent meta
[21:17] analysis and what that meta analysis
[21:19] told us is that melatonin will only
[21:22] increase total amount of sleep by 3.9
[21:26] minutes on average. Minutes, not even
[21:28] percent. No. And it will only increase
[21:30] your sleep efficiency by 2.2%.
[21:35] So the the source is not strong, the
[21:37] force is not strong in in in this one.
[21:39] When it comes to a a tool that in
[21:42] healthy people who are not of older age,
[21:47] it doesn't seem to be especially
[21:48] beneficial. Now, you know, results can
[21:51] vary. Everyone is different, of course.
[21:52] So, we're talking about the average, the
[21:54] so-called average human adult here.
[21:56] Well, melatonin um in defense of what
[21:58] you're saying and also I should mention
[22:00] I have a colleague at Stanford Jamie
[22:02] Zitzer I know Chuck Zer's lab at Harvard
[22:04] Med also trained a terrific sleep
[22:06] researcher and I asked him about
[22:08] melatonin and he essentially said the
[22:09] same thing that you just said which is
[22:11] very little if any evidence that it can
[22:13] improve sleep and yet it's probably the
[22:15] most um commonly consumed so-called
[22:18] sleep aid hundreds of million dollars
[22:20] industry the only population where we
[22:22] typically see some benefit and it often
[22:24] is prescribed is in older adults because
[22:27] as older meaning um 60 and older. Yeah.
[22:30] 60 65 and older because as we get older
[22:33] you can typically have what's called
[22:35] calcification of the pineal gland which
[22:37] means that that gland that's releasing
[22:39] melatonin doesn't work as well anymore.
[22:41] That's why older adults can have
[22:43] problems falling asleep or staying
[22:44] asleep. It's not the only reason by any
[22:47] stretch of the imagination, but it's one
[22:49] of the reasons and it's why melatonin
[22:50] supplementation in those cohorts, older
[22:53] adults, especially older adults with
[22:55] insomnia, people have thought about that
[22:58] as maybe an appropriate use case. Do we
[23:00] know how much melatonin is typically
[23:02] released into the bloodstream per night?
[23:04] Um, and can we use that as a kind of a
[23:07] rule of thumb by which to compare the
[23:09] typical amount that someone would
[23:11] supplement? I mean, typically the
[23:12] supplements for melatonin that I see uh
[23:15] in the pharmacy and elsewhere and online
[23:17] range anywhere from 1 milligram to 12 or
[23:20] even 20 milligrams.
[23:22] My guess is that a normal night's
[23:25] release of melatonin typical for
[23:28] somebody in their 20s, 30s, 40s would be
[23:30] far lower than that. Am I correct or
[23:33] wrong? Yeah, it's it's a many magnitudes
[23:36] lower. And this is one of the problems
[23:37] is that I see that too. So I see, you
[23:39] know, typical doses are, you know, 5
[23:42] millig or 10 millig. And of course, you
[23:44] know, if you're a supplement company,
[23:46] you know, putting 10 milligs versus 5
[23:48] milligs if that's what you're actually
[23:50] doing. You know, it's kind of like the
[23:52] super gulp size. You know, nobody wants
[23:55] to lower price. They just want you to,
[23:58] you know, we'll just give you more for
[23:59] the same price and that's how we'll
[24:01] compete. So it's been this escalating
[24:03] arms race of melatonin concentration and
[24:07] it really does not look meaningful for
[24:10] you know for sleep in any way. What
[24:12] we've actually found is that the optimal
[24:15] doses for where you do get sleep
[24:17] benefits in the populations that we've
[24:20] looked at are somewhere between 0.1 and
[24:23] 0.3
[24:25] millig of melatonin. In other words, the
[24:27] typical doses are usually 10 times, 20
[24:31] times, maybe more than what your body
[24:35] would naturally expect. And this is what
[24:36] we call a supra physiological dose. In
[24:40] other words, it's far above what is
[24:42] physiologically normal. I like to think
[24:45] in terms of of manipulating any aspect
[24:47] of our biology that behavioral tools
[24:50] always are the first line of entry. Then
[24:54] nutrition. Everyone has to eat sooner or
[24:56] later. even if you're fasting, then
[24:58] perhaps supplementation, then
[25:00] prescription drugs, and then perhaps
[25:02] brain machine interface devices that you
[25:04] use to induce something. And those could
[25:06] be done in combination. But what
[25:08] concerns me is when I hear people uh
[25:10] say, well, what should I take without
[25:13] thinking about their behavior, their
[25:14] light viewing behavior, etc. But of
[25:16] course, these things work in
[25:17] combination. When it comes to sleep,
[25:18] there are many lowhanging fruits that
[25:21] don't necessarily require you to, you
[25:24] know, put sort of exogenous molecules,
[25:27] in other words, things like supplements
[25:29] into your body or, you know, use
[25:31] different types of drugs to help you get
[25:34] there. Now, when it comes to
[25:35] prescription sleep aids, I think I've
[25:38] been again a little bit too forthright.
[25:41] We know in clinical practice that there
[25:44] may be a time and a place for things
[25:46] like sleeping pills. They are a
[25:47] shortterm solution to certain forms of
[25:51] insomnia, but they are not recommended
[25:54] for the long term. And we also know that
[25:57] there are lots of other ways that you
[25:58] can get a sleep um help or you can get a
[26:02] sleep curative profile from things like
[26:05] cognitive behavioral therapy for
[26:06] insomnia, which is a non-drug approach,
[26:08] psychological, and quite effective from
[26:10] what I understand. Just as effective as
[26:11] sleeping pills, great data, more
[26:14] effective in the long term. There was a
[26:15] recent study published that after
[26:17] working with that therapist, some of the
[26:18] benefits lasted almost a decade. You
[26:21] know, now if you stop sleeping pills,
[26:24] usually you have rebound insomnia where
[26:26] your sleep goes back to being just as
[26:28] bad, if not worse. And I think the same
[26:30] is true when we think about
[26:31] supplementation. There are so many
[26:33] things that are easy to implement when
[26:36] it comes to sleep that don't require
[26:39] venturing out into those waters. And
[26:41] again, we're not here to tell anyone
[26:43] about whether they should venture or
[26:44] not. That's completely your choice. All
[26:46] I'm saying is that if you want to think
[26:48] about optimizing your sleep, there are a
[26:51] number of ways that you can do it that
[26:52] don't necessarily require you to swallow
[26:55] anything or inject anything or, you
[26:57] know, smoke anything or and for which
[26:59] the margins of safety are quite quite
[27:01] wide. Right? Let's talk about naps. I
[27:04] love naps. I come from a long history of
[27:07] nappers. What are the data on naps? And
[27:11] what are your thoughts about keeping
[27:13] naps short, meaning 20 to 30 minutes
[27:16] versus getting out past 90 minutes, 2
[27:19] hours? Yay, nay or meh? Naps can have
[27:22] some really great benefits. We found
[27:24] benefits for cardiovascular health,
[27:26] blood pressure, for example. We found
[27:28] benefits for levels of cortisol. We
[27:30] found benefits for learning and memory
[27:32] and also emotional regulation. How long
[27:35] are the naps typically in those studies?
[27:37] anywhere between 20 minutes to 90
[27:40] minutes. Sometimes we like to use a
[27:41] 90-minute window so that the participant
[27:44] can have a full cycle of sleep and
[27:46] therefore they get both non-REM and REM
[27:48] sleep within that time period. And then
[27:50] we correlate how much benefit did you
[27:52] get from the nap and how much of that
[27:55] benefit was explained by what REM sleep
[27:58] you got, what deep sleep you got, what
[27:59] light sleep you got. What we've also
[28:01] found is that naps of as little as 17
[28:05] minutes can have some quite potent
[28:07] effects on, for example, learning. None
[28:09] of this is novel. NASA pioneered this
[28:12] back in the 1990s. And during the
[28:15] missions, they were experimenting with
[28:17] NAPS for their astronauts. And what they
[28:19] found was that naps of little as 26
[28:22] minutes improved um uh mission
[28:26] performance by 34% and improved daytime
[28:29] alertness by 50%.
[28:32] And it birthed what was then called the
[28:34] NASA NAP culture throughout all
[28:37] terrestrial NASA staff during that time
[28:40] period. So it's long been known that
[28:42] naps can have a benefit. NAPS, however,
[28:45] can have a double-edged sword. There is
[28:46] a dark side to naps. When you nap, you
[28:50] are essentially opening the valve on the
[28:53] pressure cooker of sleep pressure and
[28:56] some of that sleepiness is lost by way
[28:59] of the nap. Some people, however, if
[29:02] they are struggling with sleep at night
[29:04] and they nap during the day, it makes
[29:06] their sleep problems even worse. So, for
[29:09] people with insomnia, we typically
[29:10] advise against napping. And the advice
[29:13] is if you can nap regularly and you
[29:16] don't struggle with sleep at night then
[29:18] naps are just fine. But if you do
[29:20] struggle with sleep stay away from naps.
[29:23] If you are going to nap try to limit
[29:26] your naps try to cut them off a bit like
[29:28] sort of caffeine. Maybe you know 8 to
[29:31] sort of 12 hours maybe not that you know
[29:34] far off. Maybe sort of 7 to 6 hours is a
[29:37] good rule of thumb. Try not to nap
[29:39] essentially late in the afternoon. And
[29:41] if you do take a nap and you want to
[29:44] maintain your you don't want to have
[29:46] that groggginess hangover that can
[29:48] happen after a full night of sleep for
[29:49] the first hour, try to limit it to about
[29:52] 20 25 minutes. And that way you don't go
[29:55] down into the very deepest stages of
[29:57] sleep which I if I wrench you out of
[30:00] with an alarm, you almost feel worse. No
[30:03] one should feel guilty about getting the
[30:04] sleep that they need. And I think that's
[30:07] been one of the big problems in society.
[30:09] Society has stigmatized sleep with these
[30:12] labels of being slothful or lazy and
[30:15] we're almost embarrassed, you know, to
[30:17] tell colleagues that we we take a nap. I
[30:20] think sleep is a right of human beings
[30:24] and I therefore think that sleep is a
[30:26] civil right of all human beings and no
[30:30] one should make you feel unproud of
[30:32] getting the sleep that you need. Are
[30:34] there any unconventional sleep tips? The
[30:36] what if kind of things that Yeah. What
[30:39] if it turns out that, and I hear I just
[30:42] I I've got a blank there for you to fill
[30:44] in. The first one, which is
[30:46] unconventional along the lines of naps,
[30:49] if you've had a bad night of sleep, do
[30:52] nothing.
[30:54] What I mean by that is don't wake up any
[30:56] later. Don't sleep in the following day
[30:58] to try and make up for it. Don't nap
[31:01] during the day. Don't consume extra
[31:04] caffeine to wake you up, to try to get
[31:07] you through the day. And don't go to bed
[31:09] any earlier to think that you're going
[31:11] to compensate. If you wake up later,
[31:14] you're not going to be sleepy until
[31:16] later in the evening. So, you're going
[31:17] to go to bed at your normal time and you
[31:19] won't be sleeping. You'll think, "Well,
[31:20] I just came off a bad night of sleep and
[31:23] now I I still am I can't even get to
[31:26] sleep and it's my normal time." It's
[31:28] because you slept in later than you
[31:29] would otherwise. And you reduce the
[31:32] window of adenosine accumulation before
[31:34] your normal bedtime. So, don't go don't
[31:37] wake up any later. Don't use more
[31:40] caffeine for the reasons that that are
[31:41] obvious because that's only going to
[31:42] crank you and keep you awake the
[31:44] following night or decrease the
[31:46] probability of a good following night of
[31:48] recovery sleep. And then finally, don't
[31:50] go to bed any earlier. Resist and resist
[31:53] and go to bed at your normal time. What
[31:55] I want to try and do is prevent you from
[31:57] thinking, "Well, I had such a bad night
[31:59] last night and I normally go to bed at
[32:01] 10:30. I'm just going to get into bed at
[32:03] 9:00. My body is not ready to to sleep
[32:05] at nine o'clock, but I'm worried because
[32:08] I had a bad night of sleep last night.
[32:10] So, I get into bed and now I'm tossing
[32:12] and turning for the first hour and a
[32:13] half because it's not my natural sleep
[32:16] window, but I just thought it was a good
[32:17] idea. I think the second tip um I would
[32:20] offer in terms of unconventional is have
[32:22] a winddown routine. Many of us think of
[32:26] sleep as if it's like a light switch
[32:29] that we just jump into bed and when we
[32:31] turn the light out, sleep should arrive
[32:33] in that same way. Sleep is a
[32:35] physiological process. It's much more
[32:37] like landing a plane. It takes time to
[32:40] gradually descend down onto the terra
[32:42] firmer of what we call good solid sleep
[32:44] at night. Find out whatever works for
[32:47] you. And it could be light stretching. I
[32:50] usually meditate um for about 10 or 15
[32:52] minutes uh before bed. some people like
[32:56] reading. Try not to watch television in
[32:58] bed. That's usually advised. Too much
[33:00] light to your eyes. Too much light, too
[33:02] activating, you know, you wouldn't race
[33:04] into your garage and come to a a a
[33:08] screeching halt from 60 m an hour. You
[33:11] typically down shift your gears and you
[33:13] slow down as you come into the garage.
[33:14] There's the same thing with with sleep,
[33:16] too. The other thing about um sort of
[33:19] that idea of shifting focus away from
[33:22] your mind itself, get your mind off
[33:25] itself is a good piece of advice.
[33:28] Kathis, you can try to write down all of
[33:32] the concerns that you have. And do this
[33:35] not right before bed, but usually an
[33:38] hour or two before bed. Some people call
[33:40] call it a worry journal. And to me, it's
[33:43] a little bit like closing down all of
[33:45] the emotional tabs on my browser.
[33:48] Because if I shut the computer down and
[33:49] all of those tabs are still open, I'm
[33:51] going to come back in the morning, the
[33:53] computer's red hot, the fan's going
[33:55] because it didn't go to sleep because it
[33:57] couldn't because there were too many
[33:58] tabs active and open. I at first thought
[34:00] this just sounds like who it sounds very
[34:02] Berkeley. It's kind of come by our we
[34:04] all hold hands and you know, walk home
[34:06] at the end of the day. But then this the
[34:08] data started coming out really good
[34:09] studies from good people and they found
[34:11] that keeping one of those journals
[34:13] decrease the time it takes you to fall
[34:15] asleep by 50%. 50ing you know it's well
[34:18] on par with any pharmaceutical agent. I
[34:20] think the fourth sort of little tip I
[34:23] would give that's unconventional is
[34:25] remove all clock faces from your bedroom
[34:28] including your phone. Including your
[34:30] phone because if you are having, you
[34:32] know, a tough night, knowing that it's
[34:35] 3:22 in the morning or it's 4:48 in the
[34:38] morning does not help you in the
[34:41] slightest and it's only going to make
[34:43] matters worse than better. Matt, this
[34:45] has been an amazing uh deep dive on
[34:48] sleeve. It is choa block full of
[34:50] valuable takeaways. It's been a uh
[34:53] tremendously fun for me to uh dissect
[34:56] out this incredible aspect of our lives
[34:58] that that we call sleep with a fellow
[35:00] scientist and a fellow public educator.
[35:02] And um we don't just uh want to hear
[35:05] more from Matt Walker. I speak for many
[35:07] people. Um we need to the work you're
[35:09] doing is both um influential but more
[35:12] importantly it is important work. it it
[35:15] has the impact that needed especially in
[35:18] this day and age where science and
[35:20] medicine, public health and the the
[35:23] issues of the world etc are really
[35:25] converging. So I know I speak on behalf
[35:27] of a tremendous number of people and I
[35:29] just say thank you for doing the work
[35:31] you do and for being you.
[35:35] [Music]