Dr. Matt Walker: Improve Sleep to Boost Mood & Emotional Regulation | Huberman Lab Guest Series

1. 0:00 – 1:09

   Sleep & Mental Health

   1. AHAndrew Huberman0:00

      (energetic music) Welcome to the Huberman Lab Guest Series, where I and an expert guest discuss science and science-based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today marks the fifth episode in our six-episode series all about sleep, with expert guest Dr. Matthew Walker. Today's episode focuses on the inextricable link between sleep and our mental health. For instance, a specific stage of sleep called rapid eye movement or REM sleep is critical for removing the emotional content of our previous day's memories, and in doing so, provides a sort of therapy within sleep that allows us to feel emotionally restored when we wake the next morning. We discuss what happens when you are deprived of REM sleep to a small or greater degree, and we discuss how to improve the quality and quantity of your REM sleep in order to ensure mental health. We also discuss science-based protocols for reducing rumination and negative thoughts before sleep. The information shared by Dr. Walker in today's episode is sure to be critical for anyone that is either struggling with mental health issues or who simply wants to bolster their overall mental health.

2. 1:09 – 5:14

   Sponsors: Eight Sleep, LMNT & BetterHelp

   1. AHAndrew Huberman1:09

      Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero-cost-to-consumer information about science and science-related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is Eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating, and sleep-tracking capacity. Many times on this podcast, we discuss how in order to fall and stay deeply asleep, your body temperature actually needs to drop by about one to three degrees, and in order to wake up feeling maximally refreshed and energized, your body temperature needs to heat up by about one to three degrees. Eight Sleep makes it very easy to control the temperature of your sleeping environment so that it's easy to fall and stay asleep and wake up feeling refreshed. I started sleeping on an Eight Sleep mattress cover several years ago, and it has completely and positively transformed my sleep, so much so that when I travel to hotels or Airbnbs, I really miss my Eight Sleep. I've even shipped my Eight Sleep out to hotels that I've been staying in because it improves my sleep that much. If you'd like to try Eight Sleep, you can go to eightsleep.com/huberman to save $150 off their Pod 3 cover. Eight Sleep currently ships to the USA, Canada, UK, select countries in the EU, and Australia. Again, that's eightsleep.com/huberman. Today's episode is also brought to us by LMNT. LMNT is an electrolyte drink that has everything you need and nothing you don't. That means plenty of the electrolytes magnesium, potassium, and sodium and no sugar. As I mentioned before on this podcast, I'm a big fan of salt. Now, I want to be clear. People who already consume a lot of salt or who have high blood pressure or who happen to consume a lot of processed foods that typically contain salt need to control their salt intake. However, if you're somebody who eats pretty clean and you're somebody who exercises and you're drinking a lot of water, there's a decent chance that you could benefit from ingesting more electrolytes with your liquids. The reason for that is that all the cells in our body, including the nerve cells, the neurons, require the electrolytes in order to function properly. So we don't just want to be hydrated. We want to be hydrated with proper electrolyte levels. With LMNT, that's very easy to do. What I do is when I wake up in the morning, I consume about 16 to 32 ounces of water, and I'll dissolve a packet of LMNT in that water. I'll also do the same when I exercise, especially if it's on a hot day and I'm sweating a lot, and sometimes I'll even have a third LMNT packet dissolved in water if I'm exercising really hard or sweating a lot or if I just notice that I'm not consuming enough salt with my food. If you'd like to try LMNT, you can go to DrinkLMNT, spelled L-M-N-T, .com/huberman to claim a free LMNT sample pack with your purchase. Again, that's DrinkLMNT, L-M-N-T, .com/huberman. Today's episode is also brought to us by BetterHelp. BetterHelp offers professional therapy with a licensed therapist carried out entirely online. I've been doing therapy for over 30 years. Initially, it was a requirement for being let back in school, but I decided to keep up with that therapy because provided the therapy has three essential components, which are excellent rapport with the therapist, support from the therapist, and valuable insights from the therapist that we wouldn't otherwise be able to arrive at, well, then it's a terrific way to improve our mental landscape, both our emotional state and our behaviors. BetterHelp allows you to find a therapist with whom you have those three key components, and it also makes it very easy to schedule. Again, the sessions are carried out entirely online, and even if you're extremely busy or traveling a lot or have a lot of family and business obligations, BetterHelp allows you to access those therapy sessions regularly so that you can constantly improve. There's just, oh, so much data supporting that quality therapy can improve our mental health and the overall landscape of our lives. In fact, I view quality therapy as important as physical exercise, and I know many others do as well. They certainly aren't a replacement for one another, but if you're doing physical exercise, meaning resistance training and cardiovascular training, and you're doing regular quality therapy of the sort that BetterHelp can provide, well, then you're essentially doing as much as anyone possibly can to improve your mental health and physical health. If you'd like to try BetterHelp, go to betterhelp.com/huberman to get 10% off your first month. Again, that's betterhelp.com/huberman. And now for my conversation with Dr. Matthew Walker.

3. 5:14 – 17:27

   Emotions & Sleep, Amygdala

   1. AHAndrew Huberman5:14

      Dr. Matthew Walker, welcome back.

   2. MWMatt Walker5:16

      (laughs) Dr. Andrew Huberman, delight to be back.

   3. AHAndrew Huberman5:20

      During the course of this series, we've, of course, been talking about sleep, and you've talked about the biology of sleep, ways to improve, maybe even optimize one's sleep. You defined what optimizing one's sleep actually is. Talked about learning and memory, creativity, caffeine, naps, food, exercise, and so much more. Today, I'm excited that you're going to teach us about the relationship between sleep and emotion regulation but also mental health, mental health challenges. But I sometimes like to remind people that mental health includes the word health. It's not all about-

   4. MWMatt Walker5:59

      Mm-hmm.

   5. AHAndrew Huberman5:59

      ... mental illness. It's also about how to improve one's health, as well as...... ways to combat certain forms of mental illness or challenges. So, to start things off, if you could just give us the basics of the relationship between sleep and emotional states, or one's ability to regulate their own emotions.

   6. MWMatt Walker6:17

      This is an area of work that we've been, uh, interested in and doing a lot of research on for about 20 or so years now, and I would say that probably the most striking statement I can offer upfront is the following: in that 20 years of research, we have not been able to discover a single psychiatric condition in which sleep is normal. And to me, it has taught me everything that I need to know about this very intimate bidirectional relationship between your sleep health and your mental health. And you're right to emphasize that notion of mental health because we're not just going to speak about some of the sort of challenging aspects of sleep and psychiatric disorders, but we'll speak about some of the benefits that sleep can provide when you get it to turn the tables and we move in the direction, not of mental illness, but we move in the direction of mental wellness. So I'm excited sort of make sure that I, I don't fall prey to that. Stepping back still though, what about this relationship between just sleep and our basic emotional regulation and our emotional stability? I'm sure everyone has seen the example or had the example as a parent of that parent holding a child and the child is crying and they look at you and they say, "Well, they just didn't sleep well last night." As if there's some miraculous parental knowledge that bad sleep the night before equals bad mood and emotional reactivity and regulation the next day. And some years ago now, we were fascinated by this but we couldn't really unearth basic science that would help us explain what was going on and why that was so clearly the case, so we did an initial study where we took a group of healthy people, no signs of psychiatric illness or emotional instability, and we gave them a full night of sleep or we sleep-deprived them. And then the next day, we put them inside of a brain scanner and we showed them a whole range of emotional visual images ranging from very neutral all the way up to quite unpleasant and negative, and we were looking at how the brain was reacting to those emotional experiences with versus without sleep. And the structure that we'd initially focused on was a structure that you've spoken about before called the amygdala, and you actually have one on the left and the right side of your brain, and the amygdala is the centerpiece region for the generation of emotional reactions, both positive and negative, but here, we're focusing on that aversive, that negative aspect. And when we looked at that structure in people who are sleep-deprived, what we saw relative to the people who'd had a full night of sleep was a 60%, six zero, 60% increase in amygdala responsivity under conditions of sleep deprivation. That is quite a striking amplification. In fact, we, to that date, with all of our studies on sleep and sleep loss, had not quite seen an effect size within the brain that was, that was that big.

   7. AHAndrew Huberman9:35

      Uh, sorry to interrupt, but, uh, just to make sure that everyone's on the same page. So, people are being shown images with varying degrees of emotionality, including images that are known to evoke negative, averse emotions as we call them in the laboratories.

   8. MWMatt Walker9:49

      That's correct.

   9. AHAndrew Huberman9:49

      Um, could be feelings of fear, anger, disgust, revulsion, what- whatever.

   10. MWMatt Walker9:55

       Yeah.

   11. AHAndrew Huberman9:55

       Negative valence. Was it the case that sleep deprivation increased the activity in the amygdala to such images by 60% only for the aversive images or for, let's say, a neutral image, um, presented to somebody who has had plenty of quality sleep? Um, let's say it is... I'm making up the units here, it gives us two out of 10 units of amygdala activation-

   12. MWMatt Walker10:19

       Mm-hmm.

   13. AHAndrew Huberman10:19

       ... and this isn't the way neuroscience is done but for sake of discussion, is it the case then that that neutral image would provide a, you know, uh, six out of 10, uh, level of activation or was it only for aversive images?

   14. MWMatt Walker10:32

       So the way we did the analysis first was we used almost, uh, a correlation approach, so we sort of told the brain imaging analysis to say, "Look, here are the, the ratings of these pictures and they go from very neutral to increasingly negative and aversive, and show me what in the brain is reacting to that curve, that gradient curve." And sure enough, you've got the magnitude overall was 60%, but it's a very interesting point that you make because where the amygdala started to respond and that res- responsivity started to hook up in the activation and the sort of aggravation direction was much earlier in the curve of emotionality. In other words, things that previously when you've had a good night of sleep do not feel particularly emotional started to become rather emotional when you are not getting sufficient sleep. So it heightened the sensitivity of the initial triggering of the emotional response and then the more emotional it became, the more separate those two sort of a- reactivity curves became from the amygdala when you had sleep versus when you had not sleep, or had not slept I should say. To us then, the question became, well, why?Why is the amygdala so reactive and uncontrolled when you are absent sleep? And we did another analysis and what we found was that there was a structure in your frontal lobe, and the frontal lobe just sits directly, sort of if you think about your eyes and you go directly up, you're in your frontal lobe. And it was a particular part of the frontal lobe, the middle part that sits right between your eyes, something that we call the medial prefrontal cortex. And what we found was that with a night of sleep, the medial prefrontal cortex was strongly connected to the amygdala. Why is that important? It's because that part of the, your frontal lobe is very good at acting like a control rational mechanism on your deep sort of, you know, it's not Neanderthal, but your deep emotional brain centers. But without sleep, we found that that connection had been severed. And so it was almost as though without sleep, you become all emotional gas pedal and too little regulatory control brake, and so you couldn't modulate those emotions anywhere near as effectively. Now, some people may say, "Well, hang on a second, Hugh, that was a total night of sleep deprivation and that's not really relevant for me because I, I don't sleep enough." I know that from all of the previous episodes that, uh, I've gone through here, hopefully if you've listened to them. "But I'm usually maybe getting five or six hours of sleep. Is this really relevant?" So we started doing that study, we wanted to say, "Let's do an, what we call an ecological study, a more of a real world sleep restriction rather than total deprivation." (laughs) And we were about halfway through that study when a wonderful Japanese research group essentially published the study that we were doing. (laughs) And what was great is that they did it even in a more rigorous way, and essentially what they were able to do is replicate exactly what we'd found, but now by putting people on sort of less than six hours of sleep for five nights. And sure enough, you got the same response. So that was very clear to us that there is some sensitivity, there's a reason why you become so unbuckled emotionally when you are not getting sufficient sleep. It's the reason that you have almost this sort of erratic pendulum-like sort of responsivity when you're not getting sufficient sleep. That notion of I just snap... Or you apologize and you say, "Look, I am so sorry I just bit your head off. I just haven't been getting enough sleep." And so we could start to understand what in the brain was happening when you didn't get sleep.

   15. AHAndrew Huberman14:44

       It's such an important finding, uh, for a couple of reasons that maybe we can explore. Um, previously on the podcast we had a guest, um, doctor, he's a neurosurgeon, Matt MacDougall. He's the lead neurosurgeon at, um, Neuralink.

   16. MWMatt Walker15:00

       Yeah.

   17. AHAndrew Huberman15:01

       He came up through Stanford, works on deep brain stimulation, et cetera, and I love his description of what the prefrontal cortex does. It jibes perfectly with, uh, the way you describe it, which is he said, "The main function of the prefrontal cortex is to say, 'Shh' to specific brain areas under specific context." So, um, the "shh" of course is, uh, you know, his way of describing neural inhibition, so quieting of neural activity in certain brain circuits under certain conditions. Because there are conditions under which you want your amygdala activation to be very robust, uh, you know, fast and, um, there's time for, uh, you know, protecting oneself, maybe even certain situations for swift violent action to protect your family, et cetera. But the prefrontal cortex seems to be able to hold it in mind, so to speak, what the context is under which that would be appropriate-

   18. MWMatt Walker15:53

       Mm-hmm.

   19. AHAndrew Huberman15:53

       ... versus when it would be inappropriate.

   20. MWMatt Walker15:54

       And a great example of that people can think of, if all of a sudden a gun is pointed in your face, you would want your amygdala to react if it's in the real world. But if you're at the movie theaters and you see a gun pointed in your face, your amygdala doesn't really react as much. Why? Because your prefrontal cortex understood the word that you described, which is context. But in some ways it seems as though you become almost regressed to this more basic fundamental, elemental, (laughs) you know, emotional brain and the red mist descends and you really can't see much more because your prefrontal cortex seems to be absent.

   21. AHAndrew Huberman16:39

       Mm-hmm. You become very reflex driven. And we don't wanna, um, go too, uh, far a tangent of, on prefrontal cortex, but one of the most beautiful descriptions of prefrontal cortex I ever heard was also from a colleague, Eric Knudson at Stanford who's now retired, does beautiful work on neuroplasticity, and he described how when people or animals have lesions to certain regions of the prefrontal cortex, they become stimulus driven machines such that, you know, if you, if you go like this to a, you know, to a puppy or to maybe they'll look to the snapping finger, but at some point, you know, we all learn that, you know, there must be a reason for us to follow the snapping of the fingers in different locations in space.

   22. MWMatt Walker17:19

       Uh-huh.

   23. AHAndrew Huberman17:19

       But with prefrontal damage, people and animals just become like machines. Whatever stimulus is there, they orient to. And this has implications for ADHD,

4. 17:27 – 25:48

   Emotional Memory & Sleep

   1. AHAndrew Huberman17:27

      et cetera. One of the things that I want to, um, ask about to take us back to the specific relationship between sleep reduced medial prefrontal activity and emotionality is this feeling when we're sleep deprived that certain things just grate on us a bit more. You know, I had this experience recently, unfortunately there was a night where I didn't get much sleep at all, and then the next day I was on a phone call and the person I was talking to, I, I, I'm quite fond of, but they were, they had a lot of energy and they were talking, they were kind of coming at me with a bunch of stuff that they wanted to... And it just felt like...... you know, it was grating on my system, and I knew because I was sleep deprived that, you know, they were entirely well-meaning and so you just kind of resist.

   2. MWMatt Walker18:07

      (laughs)

   3. AHAndrew Huberman18:07

      But it's incredible how cold water, loud noises, uh, requests of our time, things like that become very irritating and gr- they grate on us.

   4. MWMatt Walker18:19

      Yeah.

   5. AHAndrew Huberman18:19

      When we're sleep deprived. Whereas when we're rested, it's like, "Oh yeah, okay, they're, you know, talking kind of fast or kind of loud. Okay, somebody is requesting something else, I'll put it in my list or maybe I'll defer to later." Or, you know, the- the, uh, cold shower that, you know, feels like, "Ugh, gotta get over this threshold to get into." Like, when you're rested you're like, "All right, let's do this," right?

   6. MWMatt Walker18:37

      Yeah.

   7. AHAndrew Huberman18:37

      You know, maybe even, "Let's go, I- I'm excited for it." But when you're tired, ooh, it is as if the, um, the brain is fighting for any sense of peace it can possibly get, and that peace is interrupted by almost anything and everything.

   8. MWMatt Walker18:53

      It is a grim situation, and w- we've certainly heard that from, you know, patients and individuals. It's almost as though the world that they are experiencing, they look at and they say, "You know what? You're at an 11 and I need you at a seven right now." (laughs) It is just too much. And this comes back to that result that we described, that when the amygdala crosses the threshold and says, "Okay, things are getting emotional, things are getting unpleasant, I'm gonna be responding negatively, in an angry way or a fearful way," that starts much earlier. So the threshold for triggering your emotional aversive reaction is much lower, and that's why the person's voice, when you hear it, at first normally if you'd had a great night of sleep you'd say, "Gosh, you know what? Today I really love your energy. It's- it's really, it's so infectious." Versus a day when you're not sleeping, you just think, "I just, I'm lifting my earbuds out of my ears 'cause I don't know if I can take this much longer." And so... That was where we were able to manipulate sleep one way, which is to say I dial sleep down and then I look at the emotional brain and you can see this ramping up of the emotional reactivity in these basic kind of guttural centers. But then we wanted to do the inverse. We wanted to instead see if we could insert sleep back in, in other words manipulate sleep and dial it back up. Could you get a dissipation in the emotional reaction? And here we decided to throw a second ingredient in- into the equation, not just simply looking at your emotional reactivity, but we wanted to look at emotional memory. Now, in a previous episode we've spoken a lot about sleep and memory, but there we were speaking about really quite neutral memory, textbook-like memory, fact-based memory. Emotional memory is very different, and if I were to ask you, Andrew, cast your mind back to some of your earliest childhood memories or your teen memories, and if anyone listening were to do that, my guess is that almost all of the memories that you recall are memories of an emotional nature, positive or negative. Why is that? It's because one of the functions of emotions when it comes to memory is to red flag and prioritize that experience, that memory as being salient because it's emotional, and that instructs the brain that this information in particular is very relevant to us as an organism. Why? Because the rest of the brain is shouting at me, "This is emotional." So there is something very privileged and very special about an emotional memory, like a red flag that tags it for priority in the brain. But something I started to notice when I would read the data, both the neural data and the subjective data on emotional memory, led me to get very interested in what happens with emotional memories over time, because what you will hear is that if I were to ask you, you know, recall an emotional memory, just try to remember it, my guess is that now at the time of recollection much later on, you are not having the same regurgitation of the same visceral emotional reaction that you had at the time of the experience. What that sort of turned a light bulb moment on for me was that somewhere between the initial experience and the later recollection of that emotional memory, the brain has done a very clever trick. It has divorced the emotion from the memory. So now when you come to recollect that emotional memory, let's say days later or even months later, in some ways it is a memory of an emotional event, but it is no longer as powerfully emotional itself as it was at the time of the experience. Right. And I started to wonder, is that time or is that time asleep? So we did a study and we had people experience these emotional memories, sort of essentially make emotional memories, and they were doing it inside of a scanner. And then we gave them a night of sleep or even a nap, and then we brought them back, or we just had them learn those emotional memories in the morning and then bring them back after an identical amount of time to try to soften those emotional memories, but without sleep. And we put them back in the scanner, and we were able to look to see when you come back later in that second session, is your emotional... And you recollect those experiences and you relive them, is the emotional reactivity at that second session any different to the first session? And is that different if that time elapsed has contained a full night of sleep versus you've just been awake? And what we found is that in those people who remained awake across the day, having had those emotional memories essentially implanted... Implanted sounds a little bit sort of Big Brother, I don't mean it that way, but they'd learned them.... the amygdala was just still as responsive as they were recalling and reliving and re-experiencing those emotional memories. But in those people who had the same amount of time to process the memories but had had a full night of sleep, we saw this incredible emotional amygdala depotentiation. And what that taught me was that the sleeping brain was able to almost detox the emotional memory. It is... Think about it like, um, uh, an informational orange that the emotional memory has this bitter emotional rind around it, and then you've got the informational orange in the middle. And what sleep was doing was stripping the bitter emotional rind off the informational orange so that then when you came back the next day, again, it is now a memory of an emotional event, but it's no longer triggering that strong visceral reaction. In other words, and we describe this theory as something called overnight forgetting, which is that when it comes to an emotional memory, you both sleep to forget and sleep to remember respectively, which is that you sleep to remember the information, the memory of the experience, but it is no longer emotional itself.

5. 25:48 – 29:13

   “Overnight Therapy” & REM Sleep, Noradrenaline

   1. MWMatt Walker25:48

      And from there, we built a biological model of exactly how this works because when we looked at the sleep group who'd had that full eight-hour opportunity, we asked the question because we'd measured their sleep, "What is it about that sleep that seems to provide this form of, it's almost overnight therapy? (laughs) How is it doing that? What stage of sleep is doing that?" And sure enough, what we found was that it was REM sleep, rapid eye movement sleep associated with dreaming. And the greater the amount of REM sleep, the greater the amount of emotional depotentiation, the greater the amount of sort of emotional detox that you got the next day. And one of the fascinating things that we didn't, um, quite mention in, uh, the episode where we described what is sleep and we described the different stages including REM and we spoke about the brain changes, something utterly unique happens during REM sleep. Levels of a brain chemical called noradrenaline are completely shut off. It is the only time during the 24-hour period when you see the complete cessation of noradrenaline in the brain. And of course, noradrenaline is associated with many different functions, and you've elegantly described them. One of the functions is that it's associated with emotional responsivity and the focus and that sort of strong, uh, sort of emotional energy. And people will know we speak about... It has two names, noradrenaline or norepinephrine, same thing, US, UK, but people of course are familiar with the sister chemical in the body called adrenaline. Upstairs in the brain, we can think about noradrenaline. And during REM sleep, noradrenaline is completely shut off. This stress-associated neurochemical, it's not only associated with stress, but it's associated with lots of things, but stress included.

   2. AHAndrew Huberman27:46

      Isn't noradrenaline shut off in the brain and body during, uh, rapid eye movement sleep?

   3. MWMatt Walker27:51

      No, it's not. It seems to be specifically within the brain that there is this blockade of noradrenaline, and serotonin goes down too. Whereas another chemical called acetylcholine, which is another neurotransmitter, that ramps up in the brain. So if there is a brain chemical that seems to be underlying REM sleep or dream sleep, it seems to be acetylcholine. And in fact, in some parts of the brain, you can see almost a 30% greater amount of acetylcholine in some brain regions than when we're awake. Yet on the other hand, when we think about noradrenaline and serotonin, they are both shut off. So the stress-related chemical within the brain is switched off during REM sleep. However, if you look at other parts of the brain, the memory-related centers of the brain, such as the hippocampus that we've spoken about before, and the amygdala that I just mentioned too, those are very active during REM sleep. So we laid out this biological model that is almost beautiful that REM sleep is this perfect condition for emotional overnight therapy where you can reactivate and re- sort of experience and reprocess those emotional memories, but you're doing it in a neurochemically, quote-unquote, "safe" environment that allows you to strip away the emotion from the

6. 29:13 – 30:27

   Sponsor: AG1

   1. MWMatt Walker29:13

      memory.

   2. AHAndrew Huberman29:13

      I'd like to take a brief break and acknowledge our sponsor, AG1. AG1 is a vitamin mineral probiotic drink that also contains adaptogens and is designed to meet all of your foundational nutritional needs. By now, I'm sure you've all heard me say that I've been taking AG1 since 2012, and indeed that is true. Now, of course, I do consume regular whole foods every day. I strive to get those foods mostly from unprocessed or minimally processed sources. However, I do find it hard to get enough servings of fruits and vegetables each day. So with AG1, I ensure that I get enough of the vitamins, minerals, prebiotic fiber, and other things typically found in fruits or vegetables, and of course, I still make sure to eat fruits and vegetables, and in that way provide a sort of insurance that I'm getting enough of what I need. In addition, the adaptogens and other micronutrients in AG1 really help buffer against stress and ensure that the cells and organs and tissues of my body are getting the things they need. People often ask me that if they were gonna take just one supplement what that supplement should be, and I always answer, "AG1." If you'd like to try AG1, you can go to drinkag1.com/huberman to claim a special offer. You'll get five free travel packs plus a year supply of vitamin D3 K2. Again, that's drinkag1.com/huberman.In

7. 30:27 – 38:27

   Sleep to “Remember & Forget”, Trauma; REM Sleep

   1. AHAndrew Huberman30:27

      some ways, it does resemble behavioral desensitization therapy, whereby under the care of a qualified psychiatrist or psychologist, somebody will, um, be encouraged to recall, in a great degree of detail, some very difficult, maybe even traumatic event. Um, and through repetition, and of course, through the knowledge that there's support in the immediate environment that will allow them to, um, you know, safely move through that experience. You know, should their, their heart rate go up, they're sweating profusely, having trouble getting the words out, you know, it's very unfortunately, uh, common features of trauma and, and negative memories. But the idea, as I understand, is to repeat the recall many times often in that safe environment, such that eventually what was initially a really terrible event remains a terrible event, but the emotional load of that event is removed from the person's sort of neural understanding of the event. Uh, the way I've heard it described is what starts as a tragic, traumatic story eventually becomes a kind of a sad, boring story. Boring to the person who's saying it-

   2. MWMatt Walker31:48

      Mm-hmm. Right.

   3. AHAndrew Huberman31:48

      ... meaning it doesn't evoke as much autonomic arousal.

   4. MWMatt Walker31:52

      Exactly. And in some ways, that's the perfect description of this overnight therapy process, that it becomes a memory that is no longer triggering an emotional reaction, and in some ways, that's what you want. If you go back to my description from an evolutionary perspective, I told you that one of the functions of emotions is to red flag and prioritize the memory at the time of learning to say that it's important. That's a very adaptive process. It helps us prioritize which things we sh- really should be focusing on and remembering. But it's not adaptive for you to hold onto that emotion long-term once you've stored it. And there has been some suggestion in the literature b- before we were doing this work, that maybe one thing you can do with trauma, uh, and trauma memories is sleep-deprived individuals the very first night after the trauma, because we knew at the time, sleep is important for memory. And what you would like to do, uh, and- and it's very similar to that movie, Sunshine Spotless Mind. I always forget the...

   5. AHAndrew Huberman32:57

      Eternal...

   6. MWMatt Walker32:58

      ... Eternal Sunshine of the Spotless Mind. Thank you.

   7. AHAndrew Huberman33:01

      I didn't, I didn't see the movie, but I hear it's good.

   8. MWMatt Walker33:03

      Um, yeah. And what they try to do is target in the brain these, you know, difficult, painful experiences, and just excise them from the brain. And that was the suggestion. Could you pop those memories out of the biography of that individual and save them the trauma? I would argue that's not really what you want to do, because let's say that I am... I have, uh, a trauma experience where I was walking home at night from the sleep laboratory late at night, and I was coming down the... uh, kind of an alley to take a shortcut, and someone sticks me up with a gun, maybe some violence. I don't want to remove that memory. I would like to remove the trauma response associated with that memory. But I would argue for me as an organism, it's still very important for me to remember that that alley was associated with a bad experience, and I should forego going down that very same route again. I want to hold onto the memory, the information. I want to let go of the emotion. I want to sleep to remember, and I want to sleep to forget. And I'll come on to why I think that's relevant to PTSD when we perhaps speak about that condition, and it's very, very relevant. But coming back to REM sleep, we looked back in the literature to see if we could find signs that REM sleep had this relationship w- with even just your basic emotional reactivity. And there was some wonderful work by a gentleman that you will know from Stanford, probably one of the founding fathers of modern-day sleep research, a gentleman called William Dement.

   9. AHAndrew Huberman34:45

      Yeah, who passed away a few years ago.

   10. MWMatt Walker34:48

       He did.

   11. AHAndrew Huberman34:48

       Um, might have been one of the people who coined the term rapid eye movement sleep, but I don't think he was the one who discovered it, correct?

   12. MWMatt Walker34:55

       He was not, but he was well up there in terms of understanding both sort of what its term was and also what its function was.

   13. AHAndrew Huberman35:03

       Mm-hmm.

   14. MWMatt Walker35:04

       He, legend as he was, very early on... This was probably in the '60s. He would take individuals, because we didn't really have the first published report of these two types of sleep, of REM and non-REM, until they collected the data or found the data in 1953. It was published in 1954. So, in other words, we discovered that, you know, even up to then, prior to then, we just thought sleep was sleep. (laughs) We didn't have any knowledge that there w- these different stages... So in the same year that, um, Francis Crick, you know, un- unveiled this incredible helical structure that was called a DNA strand, we also discovered the different stages of sleep. But in the '60s then, William Dement, knowing that there were these two types of sleep, and knowing that there was something that was going on with REM sleep where people were dreaming, and he would be waking people up from these different stages and found that it's far more likely to pe- for people to report a dream, he wondered what the consequence would be if you selectively deprive people of this stage of sleep, of dream sleep. So, he brought individuals into his laboratory, and every time f- they would go into REM sleep, they would go into the room, they would wake them up, have them do some mathematical problems for two or three minutes, and then put them back asleep, and they go back into non-REM. And then as soon as they went back into REM, they would wake them up again. And the first night they, would have to go into the room maybe six or seven times.

   15. AHAndrew Huberman36:35

       Still brutal for the... uh-

   16. MWMatt Walker36:36

       Brutal.

   17. AHAndrew Huberman36:37

       ... for the person in the experiment.

   18. MWMatt Walker36:39

       It's not, not too much fun. And by the end of...... the five days or six days, I think they were going back into the room something like 17, 18 times. Why? Because the people were building up this growing REM sleep debt and the brain had such a hunger for it that by night five of no REM sleep, all it wanted to do was rocket into this thing called REM sleep and start devouring it with high volume. But that wasn't the interesting part. The interesting part was the consequence to these subjects. They were all well-adjusted, perfectly normal individuals. By about day three of selective REM sleep deprivation, they started to show signs of paranoia, they started to believe people were out after them, they started to have hallucinations and delusions. And by day five, they were bordering on having, you know, aspects of quite severe psychosis. And so what all of this research has taught us in some ways is that it's almost as though REM sleep, and again, it's hyperbolic, is the difference between sanity versus insanity. It's the thing that separates those two. And there's a wonderful quote from an American, uh, entrepreneur called E. Joseph Kossman, and for all of the years of work that we've been doing in this field, and I s- I've spilled so much ink over this, including in the, the book, he summarized it in a single sentence: "The best bridge between despair and hope is a good night of sleep." And that's exactly what the data is demonstrating in terms of basic emotional brain function.

8. 38:27 – 47:08

   Hinge Analogy; Motivation, Impulsivity & Addiction

   1. MWMatt Walker38:27

   2. AHAndrew Huberman38:27

      Such a powerful link there, and, um, I think it's appropriate therefore if we explore a little bit about what the link actually consists of, um, in a way that will provide people a, a kind of a, a compass for when they're feeling a little bit less emotionally regulated or if they would like to improve their levels of emotion regulation. Uh, this is going to be a little bit of an exploration, but, uh, you may recall, this is an exploration that you and I had some years ago when we were talking about the relationship between rapid eye movement sleep and emotionality, and y- here you've described that the medial prefrontal cortex normally plays this kind of shh role, uh, this suppressive role over the amygdala under conditions where there is something to consider, is it averse, is it not averse? How averse is it, right? Um, but in terms of what we know about stress and emotion, you have the autonomic nervous system, this incredible system that balances sympathetic, meaning alertness, arousal, sometimes called the fight or flight system, and parasympathetic activation, sometimes called the rest and digest system. It's the balance of the two that dictates one's emotional state and alertness, um, level of stress, et cetera. And I've always imagined the autonomic nervous system, the sympathetic and parasympathetic nervous system as sort of a seesaw.

   3. MWMatt Walker39:49

      Yeah.

   4. AHAndrew Huberman39:49

      But on this seesaw sits us, right?

   5. MWMatt Walker39:53

      Mm-hmm.

   6. AHAndrew Huberman39:53

      And we can move back and forth across this seesaw, but there's an component of the seesaw that, um, in, in my mental model, um, which is the hinge, how tight the seesaw is, meaning how easily or how challenging it is to tilt the seesaw off to one or the other side.

   7. MWMatt Walker40:12

      Mm-hmm.

   8. AHAndrew Huberman40:13

      And I don't know if the mechanism has been discovered, but I feel like what happens under conditions of REM deprivation or sleep deprivation, that is sleep deprivation but you've beautifully described how it's REM deprivation in particular that can do this, that the hinge becomes loose. But the hinge doesn't become loose toward us becoming more parasympathetic and relaxed, there's an asymmetry there.

   9. MWMatt Walker40:38

      Yeah.

   10. AHAndrew Huberman40:38

       It's as if the seesaw now wants to flop to sympathetic activation until we're so exhausted that we just disappear into our sleep. So the question is this, and maybe all we have here is, is, uh, opportunity for speculation, but is there any understanding of what the hinge might be and how sleep would adjust the tightness of that hinge?

   11. MWMatt Walker41:00

       Yeah.

   12. AHAndrew Huberman41:00

       And if people are following this, what we're really trying to get to is, you know, you described a neural circuit mechanism within the brain, but is this, for instance, the gating of the release of epinephrine, adrenaline, and cortisol? I mean, is that... I could imagine that's regulated by the brain, but when we're deprived of REM sleep, that process becomes less poorly gated and then we just will punch out a bunch of adrenaline in response to, you know, a phone call from a close friend that you adore, but as their voice is just a little bit loud and you're like, "Ugh, this is rough."

   13. MWMatt Walker41:31

       Yeah.

   14. AHAndrew Huberman41:32

       Et cetera. Do we, do we understand the nature of the hinge?

   15. MWMatt Walker41:35

       We do a little bit and it's something that we started off trying to test with one specific, um, belief, and then we were beautifully course-corrected by the data. We thought that the hinge was going to be once you were sleep-deprived and you started to slide down into that fight or flight branch, the more pa- sympathetic and away from the, the parasympathetic, that the hinge would get ever tighter the further into that sympathetic stress-related fight or flight dip that you had, and there you would stay. It wasn't quite that simple. What we found was that when I challenge you or put you either under a very simple cardiovascular challenge, let's say I'm just having you grip a bar for a long period of time or we have you under some other maybe even if it's a, um, an exercise regiment, when you are in a sleep-deprived state and you are largely inert and not interacting with the world, you actually are in a more strong parasympathetic state. It's almost as though you do not want to interact with the world per se. And this comes on to motivation.We and others have found that one of the earliest and strongest effects of a lack of sleep is just absence of motivation. I don't want to interact with the world, I don't want to be social, I don't want to learn, I don't want to exert effort, I don't want to exercise, I just don't want to do much of anything. However, when you provoke me and you force me to interact or there is a very strong emotional event that I experience, I go all the way over into the strongly sympathetic. So it's almost as though we had the prediction that there was going to be a very tight hinge and the screw was tightening the more sympathetic you became. It was much more that you were in this sort of para-sympathe- parasympathetic state, this sort of non-motivational state, and the, the hinge was so loose however, that even just the tiniest flick of a challenge, whoosh, you went straight over to the sympathetic. There was no sweet spot of a tightening where you were nicely balancing between those two states. And this comes back to something else that we found, that's you switching, flip-flopping back and forth between parasympathetic and sympathetic. I spoke about the emotional reactivity to negative aversive events, but that's only one-half of what we call the affective valence domain. It's not just that you can have negative emotional reactions, of course you can have positive emotional reactions. So we did a sister study to that amygdala study and we asked rather than showing you increasingly negative images and how your amygdala would respond much more strongly to those as we provoked it, we then started to show you much more positive rewarding images. And because one hypothesis would be that you just simply slide down the scale when you move towards more negative and away from more reward-based reactivity. Or, you could imagine that it's both, that when you are sleep deprived, you are equally excessively reactive to both of those domains. And what we found was that it was the latter, that you were very abnormally reactive, over-reactive to negative events, but you were equally hyper-sensitive to very reward-based stimuli, and this fits beautifully with what we know from sleep deprivation. You are much more impulsive, you are much more reward-seeking, you are much greater in terms of your sensation-seeking, and your addiction potential when you are not getting sufficient sleep is significantly higher, and sure enough, when we looked in the brain, many of these dopamine-related circuits that you've described before were overactive when you were under-slept. And so I bring this back because it relates to your see-saw sort of analogy. Yes, you can think about the see-saw from with sleep deprivation from a sympathetic, para-sympathetic. You can also think about it from a positive versus negative valence, and once again, our hypothesis was that you're just going to slide down into the negative and you're just gonna be less responsive to the rewarding positive. It was the opposite, you were abnormally and excessively sensitive to both of those domains, which you could argue is perhaps the very worst of all adaptive responses.

   16. AHAndrew Huberman46:32

       Absolutely.

   17. MWMatt Walker46:33

       As an organism, you don't want to be non-reactive. Emotions are powerful and we've spoken about the benefits, you need to have emotions to be a functioning human being or organism in the world. They are designed to adaptively help us survive. But you can't go to the extremes. That's maladaptive rather than adaptive, but that's where you go when you are sleep deprived. It's this loose hinge and you become very, very erratically and extremely reactive from a neural perspective.

   18. AHAndrew Huberman47:07

       Mm-hmm.

9. 47:08 – 56:18

   Tool: Improve REM Sleep, Social Jet Lag, Alcohol & THC, Addiction

   1. AHAndrew Huberman47:08

      Yeah, my understanding is that, um, you know, sleep deprivation definitely increases impulsivity and addictive potential. It's, um, yeah so best, uh, worst of both worlds in this case. And, uh, and given that, um, now would probably be an appropriate time to just, um, cue people to some of the things that they can do to improve or maximize their rapid eye movement sleep. This was covered in detail in episodes one and two, um, and to some extent in episodes, uh, three and four as well, but they're in reference to, um, to other things, um, learning memory, creativity, the role of naps etc. And I'll refer people back to this, um, beautiful formula, uh, QQRT that it's not just about getting enough sleep, it's about the quantity indeed, but also the quality QQ, regularity, and timing of sleep, and knowing one's chronotype, that is the best time to go to bed and the best time to wake up in the morning for them is going to be critical here, and, and I can raise my hand, I'll raise both hands in fact, uh, metaphorically and say that when I've gone to sleep early and woken up early, so for me, 8:30, 9:00 PM wa- and then waking up at 4:30, 5:00 AM which for me, matches my chronotype. Uh, it has served as a powerful antidepressant effect, and when I've gotten it, an equal amount of sleep but going to bed too late for me, that is, you know, midnight, 1:00 AM and sleeping in until 8:00 or 9:00 AM, um, I always carry a low-level depression. Um, fortunately not something that needed to be, uh, medicated but, uh, it's, it's a striking effect in the positive direction when-... obeying QQRT and in an- in the negative direction when not. So maybe just for, because we can find some links to, um, those segments in the show note captions, but maybe just, um, for people that are here now, um, if we were going to list out, you know, two or three things that one can do to try and maximize, um, the quality and quantity of REM sleep, uh, without going on too much of a tangent. But, um, at the same time, we do wanna highlight that addressing that QQRT formula, um, for ourselves is going to be critical. So maybe... So for REM sleep, um-

   2. MWMatt Walker49:28

      Yeah.

   3. AHAndrew Huberman49:28

      ... you know, in the domain of exercise, temperature, et cetera, are there- are there any kind of quick, quick bullet points that we can, uh, refer people to?

   4. MWMatt Walker49:35

      I would say, just to keep it high level and- and brief, the single best way, cheapest, non-pharmacological way that you can enhance your REM sleep is to just sleep an extra 15 or 20 minutes later into the morning. Don't try to put... If I tell you this is about... By the way, this is about the- the quantity, the- your sleep opportunity. Don't try to add that 30 minutes or 20 minutes if your goal is to increase REM sleep at the start of the night, at the front end. Instead, take that desire that I've offered you of adding just 20 minutes or 25 minutes of extra sleep now to the last part of your night. Wake up that sort of much later, 20, 25 minutes later, that's the REM sleep rich phase. So if people go back and listen to episode one, we'll describe to you exactly how the different stages of sleep unfold across the night. And they're not evenly distributed, it's not as though you get just as much REM sleep as well as deep non-REM sleep in the first half of the night as you do in the second. You get most of your deep sleep in the first half and you get most of your REM sleep in the second half, and particularly in the last quarter of the night. And this leads us to understand that the later into the morning hours that we go, the greater the hunger preference and the taste desire that is of your brain to start sampling from the finger buffet of all of those different stages, this thing called REM sleep. And the later that you sleep into the morning, the more of that REM sleep that you will have. And many people will have experienced this at the weekend, where they have this pattern that we don't reco- recommend based on the QQRT, um, QQR regularity, goes to bed at the same time, wake up at the same time. What we see often in society is something what we call social jet lag, where you're short sleeping during the week and then at the weekend you're out with friends or you're out sort of on the town, you go to bed late and you wake up late, and maybe you are doing that by two hours. Maybe you're normally in bed by 10:00 PM during the week, but now at the weekends you are going to sleep maybe 12, 12:30 and you're waking up two, three hours later on a Saturday and Sunday. And then the problem with that, parenthetically, is on Sunday evening you've now got to go back to work the next day, so you have to push yourself back to 10:30 or 10:00. Whereas you were going to bed, let's say, at 1:00 AM on Friday and Saturday night, that's a three hour time shift, and people are doing that very frequently. That's the equivalent of you and I flying back and forth from Los Angeles to New York every single weekend in terms of our circadian rhythm, and it's brutal on it. But this is separate from this notion of your timing the final part of the QQRT, and by pushing your timing a little bit later into the morning when you wake up, you will experience more REM sleep. And as I said, when people sleep later, they go to bed later at night and they wake up much later in the morning at the weekend, I strongly suspect that if they paid attention, they would say, "At weekends I always dream more. I always can remember my dreams and they're more intense." It's not because there's something magical about how your memory recollection of dreams operates on Saturdays and Sundays, it's because you've slept in later, you've gone into that REM sleep rich preferential phase in the morning and therefore you've increased your REM sleep. So I would say that that's probably the easiest way that you can-

   5. AHAndrew Huberman53:22

      Mm-hmm.

   6. MWMatt Walker53:22

      ... start to modulate REM sleep.

   7. AHAndrew Huberman53:24

      So it's a terrific do and, um, I think we can probably summarize the- the top don't as, uh, don't drink alcohol because it abolishes REM sleep.

   8. MWMatt Walker53:33

      Alcohol and THC are both very potent ways that will remove or o- obliterate your REM sleep. And we spoke about this in the episode o- on, um, on THC when we discussed this. I think just yesterday I got a very long email and, you know, I'm sure you get lots of emails from, um, from delightful people in the public. And a gentleman just saying, you know, "I was using cannabis for probably about seven years and then I watched, um, or listened to some of your content and I stopped and I just had this explosion of dreams. And I was never recollecting any of my dreams before, but now they came back and goodness were they vivid, they were rich, they were... And I could not believe it." And-

   9. AHAndrew Huberman54:23

      And that's REM sleep.

   10. MWMatt Walker54:24

       And that's because during the cannabis use by way of the THC, not the CBD, you've been blocking that REM sleep, you've built up that pressure just as we described in the dementia studies. And then when you finally do take away the agent that is blocking the generation of REM sleep, the THC, all of a sudden your brain doesn't just go back to having its standard amount of REM sleep and dreaming. It has that plus it tries to get back as much of it as it possibly can by...... having what call a REM sleep rebound, and that's why people, when they, they stop using, they end up having this intense REM sleep. By the way, to your point about reward and, um, addiction sensitivity with sleep deprivation, one of the things that we, um, we did in a collaboration, gosh, this was years ago when I was at Harvard, with Carl Hart, who I think you, I, I don't know if you-

   11. AHAndrew Huberman55:17

       At Columbia.

   12. MWMatt Walker55:17

       Yeah. At Columbia. You, you know him. Yeah. He's fantastic researcher, very interesting man too. Um, and what we found was that a lack of sleep was not only predictive of your addiction potential, but when you went into a clinic to abstain and trying to come off some of those, and here we were looking at cocaine, um, addiction, a lack of sleep was a strong predictor of your abstinence and you falling off the wagon and going back to use. So sleep is so critical, not just for, um, maintaining or pushing you away from that addiction potential, but once you are addicted and you're trying to abstain, it gives you that lift of altitude to try to resist falling off the wagon. And when sleep gets short, that's when you become vulnerable again, probably because your reward circuitry becomes enhanced and all of a sudden you just cannot resist the temptation anymore.

10. 56:18 – 57:23

    Sponsor: InsideTracker

    1. AHAndrew Huberman56:18

       I want to take a brief break and acknowledge our sponsor, InsideTracker. InsideTracker is a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and help you reach your health goals. Now, I've long been a believer in getting regular blood work done for the simple reason that many of the factors that impact your immediate and long-term health can only be analyzed from a quality blood test. The problem with a lot of blood tests out there, however, is that you get information back about metabolic factors, hormones, et cetera, but you don't know what to do with that information. With InsideTracker, they make it very easy to understand your results, and they also point you to specific directives that you can follow in the realm of nutrition, exercise, supplementation, even prescription drugs that can help bring the levels back into the ranges that are optimal for you. InsideTracker also offers InsideTracker Pro, which enables coaches and health professionals to provide premium and personalized services by leveraging InsideTracker's analysis and recommendations with their clients. If you'd like to try InsideTracker, you can go to insidetracker.com/huberman to get 20% off any of InsideTracker's plans. Again, that's insidetracker.com/huberman.

11. 57:23 – 1:06:53

    Post-Traumatic Stress Disorder (PTSD) & REM Sleep

    1. AHAndrew Huberman57:23

       I think the takeaway is very clear. In order to be your best emotional self, that is in order to be able to access positive emotions to their full amplitude, uh, motivation, um, learning as we also covered in a previous episode, but also to stay out of those, um, irritable emotional traps of life, um, and to be a regulated person, calm and, and joyful person, um, it stands to reason to, uh, minimize alcohol and cannabis use unless there's some, I don't know, medical reason why, uh, someone should do otherwise. But the, the real take home message here is get as much rapid eye movement sleep as possible and don't do anything to inhibit it.

    2. MWMatt Walker58:03

       Yeah. Get as much sleep. So focus on all of those four, uh, macros of sleep, constant, quality, regularity, and timing. And notice that if you want to try optimize some of those, that emotional reactivity imbalance, you may want to slightly over index on your REM sleep in that regard. And one easy, cheap way of doing that, if you can, lifestyle permitting, and again, of course I understand everyone is, has a life to live and pressures, but that's the way that if you were to ask me, "Can you do it and do it simply?" Yes, you probably can.

    3. AHAndrew Huberman58:37

       Great. Well, we, you touched on trauma a little bit already, but, um, now would be the appropriate time, I think, to talk about PTSD, post-traumatic stress disorder-

    4. MWMatt Walker58:45

       Mm-hmm.

    5. AHAndrew Huberman58:45

       ... which, um, I think we can use the definition of PTSD and trauma that the great Paul Conti, a former guest on this podcast who also did an expert series-

    6. MWMatt Walker58:56

       What a wonderful, epic man. Yeah.

    7. AHAndrew Huberman58:56

       Yeah. An incredible man. What a, what a, what a mind on him, and what a generosity of, of sharing information in clear ways about mental health as he did in the four episode series on mental health here, and he's been on other podcasts as well. Wrote a marv- marvelous book on trauma. Paul defined trauma as some event that is aversive, that changes the way that our nervous system works such that we function less well in the future. It's not that every negative event, every, uh, negative emotion associated memory is trauma. I think that's a, a misconception.

    8. MWMatt Walker59:33

       Yeah.

    9. AHAndrew Huberman59:33

       Um, but there are things that happen to people, um, or that they observe happening to other people. So there's, you know, first person trauma, third person observational trauma, et cetera. And these can be single events, multiple events. You know, sadly, this stuff happens. Um, it can be neglect, so sometimes it's the absence of an event, right? Which becomes the traumatic event that fundamentally rewire some component of ner- neural circuitry such that we don't function as well in terms of relationship to anything, work, food-

    10. MWMatt Walker1:00:05

        Mm-hmm.

    11. AHAndrew Huberman1:00:05

        ... sex, sleep, relationships, uh, baseline levels of emotionality, and on and on. So what is the relationship between sleep and post-traumatic stress disorder specifically? I think some of what we've covered already certainly touches on this.

    12. MWMatt Walker1:00:20

        Yeah.

    13. AHAndrew Huberman1:00:20

        But PTSD seems to me that it, it might be its own unique case.

    14. MWMatt Walker1:00:26

        It is because if you look at the diagnostic criteria for PTSD, firstly, you see sleep disturbance. And as I said right at the top of this episode, there is no major psychiatric disorder where there isn't some mention of sleep problems in its diagnostic criteria. But something else was intriguing about PTSD that compelled me to think about it and then create a theory around it. It's not just sleep problems. It's also nightmares.... and specifically repetitive nightmares. In fact, repetitive nightmares form part of the diagnostic criteria for you to receive a diagnosis of PTSD. That's how reliable they are. And as I thought more about this model of overnight therapy, this notion that sleep, and particularly REM sleep, provides a form of emotional first aid, PTSD stood out to me as something that I had to return to, to explain. Why? Because if you think about PTSD and a veteran, it is the perfect example of the process that I described of emotional depotentiation failing. Because what I started to realize is that in PTSD, there is this trauma experience and then perhaps what's happening is that sleep, the brain goes back to sleep that night and says, "Okay, please do your elegant trick of stripping away the emotion from the memory," and it fails. So then what happens the next night? The brain comes back and says, "I'm sorry, but I still got this very emotionally charged memory. Please do your elegant dissipation, depotentiation of the emotion from memory." And it fails again, almost like this broken record that was so indicative of these repetitive nightmares. And then when you looked at PTSD, I told you that REM sleep is a time of this remarkable decrease in noradrenaline. But if you look at PTSD patients, they actually have heightened levels of noradrenaline and also in the body, adrenaline as well.

    15. AHAndrew Huberman1:02:43

        In sleep?

    16. MWMatt Walker1:02:44

        In sleep, and also when you look just as a basal state as well. So there's something not quite right with the noradrenaline story in REM sleep in PTSD patients. So I had just published this paper and I was up, um, at a conference in, I think it was Portland, and I presented the theory that, well, the data that we had on healthy people and I put forward this theory of, um, of PTSD. And then later that afternoon, a psychiatrist came on, uh, the stage called Murray Raskin, and he was working a lot with PTSD vets and he described data which I couldn't believe. It's one of those moments, Andrew, where you're at a scientific conference and I think it happens maybe once in a career if you're lucky, all of the hairs on the back of my neck stood on sharp end because he was saying, "We've got this data and we don't quite understand it. We've been treating our veterans for blood pressure, for hypertension using a generic drug called Prazosin." And Prazosin blocks the, um, adrenergic response in the body because you're trying to sort of tamp down that sympathetic-

    17. AHAndrew Huberman1:04:02

        Mm-hmm.

    18. MWMatt Walker1:04:02

        ... activation in the body and reduce the-

    19. AHAndrew Huberman1:04:04

        So it's a beta blocker.

    20. MWMatt Walker1:04:05

        So it's an, uh, it's an alpha-adrenergic-

    21. AHAndrew Huberman1:04:08

        Okay, so not a-

    22. MWMatt Walker1:04:09

        ... antagonist.

    23. AHAndrew Huberman1:04:09

        Not a beta blocker.

    24. MWMatt Walker1:04:10

        Uh, so it's not a beta blocker, but it's blocking the adrenergic system.

    25. AHAndrew Huberman1:04:14

        Mm-hmm.

    26. MWMatt Walker1:04:15

        And so... And it's a, you know, it's a generic, pretty cheap drug, but it turns out that it crosses the blood–brain barrier, so it doesn't just stay within the body. It goes up into the brain. And he said, "We don't really understand it because I've been giving patients this medication and it works to a degree, but something else happens. They come into the clinic and they say, 'Doc, I'm not having those nightmares anymore. They seem to have gone away.' And these patients seem to start to show signs of resolution." So all of a sudden, I had had a model, a clinical model that was in search of data, and he had data that was in search of a theoretical model. I, I couldn't believe it because it's exactly what I would predict, which is that if noradrenaline is too high in PTSD, you're not processing and stripping the emotion from the memory, so it keeps coming back over and over like this repetitive nightmare. But then if you block and help bring back down that level of noradrenaline to that which would be seen in a normal healthy person, in other words completely blocking it, all of a sudden the emotional memory gets the chance to be processed and you finally start to get symptom resolution. So we couldn't believe it. He flew down to Berkeley, we spent several days together. We went out to dinner. We just could not stop talking. He subsequently did some incredible work in this area and Prazosin went on to become the, um, an FDA approved medication for PTSD and repetitive nightmares that was approved by the Veterans Administration.

    27. AHAndrew Huberman1:05:55

        Bravo.

    28. MWMatt Walker1:05:55

        And so, no, it's not me. It's all hi- uh, all of his work, but to, to-

    29. AHAndrew Huberman1:06:00

        No, no, no, no, no, no, no. You can't... Uh, no, this to me is the, uh, scientific collaborative, um, conceptual equivalent of the old, uh, Reese's, um, Peanut Butter Cup commercials. Uh, for those of us old enough to remember, it's two people running toward one another on the beach.

    30. MWMatt Walker1:06:12

        (laughs)
12. 1:06:53 – 1:09:40

    Noradrenaline & REM Sleep, PTSD & Prazosin

    1. AHAndrew Huberman1:06:53

       I, I have a question about, um, this notion of blocking norepinephrine, um, in the brain and body. Um, you know, on the one hand it seems that during rapid eye movement sleep-We know we're paralyzed, um, or we are paralyzed, that's a fact of rapid eye movement sleep. The, um, the brain is recalling memories often in, in great detail, sometimes through symbolic representations, space-time is disrupted, it's either-

    2. MWMatt Walker1:07:21

       Mm-hmm.

    3. AHAndrew Huberman1:07:21

       ... fast or slow or so because you're dreaming. Um, and it seems that there's something powerful about being able to replay the memories and yet divorce them from certain neurochemical, uh, release in the brain and body to essentially uncouple them.

    4. MWMatt Walker1:07:39

       Hmm.

    5. AHAndrew Huberman1:07:39

       And then to me, it makes perfect sense why taking a, a drug that would reduce the amount of sympathetic arousal in sleep would help, especially PTSD because you said with PTSD, sort of an invasion of the noradrenaline response into rapid eye movement sleep that is inappropriate. So does that mean that rapid eye movement sleep in people with PTSD is not truly rapid eye movement sleep, it's as if it's been abolished and replaced with something that's kind of pseudo-waking stress invaded, you know, it's like a zombie REM, um, and it's not good. Is that, is that, is that correct?

    6. MWMatt Walker1:08:14

       It seems to be and, eh, and you can look at this in terms of the electrical activity of REM sleep, the electrical brainwaves of REM sleep in these patients. And you're right, it doesn't seem to be of the same electrical quality, but what was interesting in Murray Raskin's studies when he started to treat patients with the prazosin and tamp down that noradrenaline, one of the other things that returned back to normality was not just that the symptoms dissipated, their REM sleep started to return-

    7. AHAndrew Huberman1:08:43

       Mm-hmm.

    8. MWMatt Walker1:08:44

       ... with, uh, a greater amount. And so I think it fits very well with this notion that whatever REM sleep that was going on may not necessarily have been electrically or neurochemically identical to normative REM sleep, but when you assisted the system with a chemical to bring it back into normality, REM sleep was gifted back to the brain and emotional resolution started to unfold. Now, I should note that there have been, um, a number of studies that have replicated the finding, some studies have not though, and so we still need to understand exactly why this is the case and there are other therapies that we'll probably discuss in a later episode on dreaming that are as, if not more effective than that drug therapy for repetitive nightmares that is a psychological intervention rather than a pharmacological intervention, and that seems to be very effective too.

13. 1:09:40 – 1:16:46

    Addiction, Non-Sleep Deep Rest (NSDR); Liminal States

    1. MWMatt Walker1:09:41

    2. AHAndrew Huberman1:09:41

       In 2017, as my laboratory was starting to explore some studies on humans on fear and trauma, I visited a, uh, trauma addiction center on the East Coast, um, the guy who runs it will be a guest on this podcast in the future, uh, an amazingly talented, uh, trauma and addiction therapist by the name of Ryan Swav. And there it was that I learned about yoga nidra, non-sleep deep rest, and here's why. They were taking heroin addicts, gambling addicts, sex addicts, alcoholics, people with what they call behavioral process addictions and substance abuse addictions, um, and every morning after they woke up, the first thing that they would do was one hour of non-sleep deep rest, you know, placing people into this liminal state and I asked, "Why?" And, um, and Ryan said, "This is especially important to do with, um, addicts when they arrive in in-patient recovery in the first week and, um, even more so in the first three days because typically they are badly sleep-deprived."

    3. MWMatt Walker1:10:42

       Mm-hmm.

    4. AHAndrew Huberman1:10:43

       "And in addition to that, many of them are just not good at getting and staying asleep at night without the use of pharmacology or-"

    5. MWMatt Walker1:10:51

       Yeah.

    6. AHAndrew Huberman1:10:51

       "... in some cases their behavioral addictions depending on what it, what it was." And so it was a, a kind of a self-directed relaxation training of sorts, uh, first thing in the morning that in addition, um, perhaps could compensate partially for some of the sleep deprivation that they no doubt were experiencing when they arrived. It's also novel environment and-

    7. MWMatt Walker1:11:11

       Mm-hmm.

    8. AHAndrew Huberman1:11:12

       ... sleeping in novel environments can be challenging so, uh, there is as far as I know no, uh, randomized control trials of, of this practice, uh, yet, but there are a good number of, um, clinics and treatment centers that are now employing non-sleep deep rest, AKA yoga nidra, um, for 30 minutes to an hour first thing upon waking, um, as one of the, you know, core components of treatment for helping people get and stay sober.

    9. MWMatt Walker1:11:40

       I think it's absolutely fascinating because that morning time period as well can be for those who are struggling with sleep especially difficult, and you and I have spoken on this podcast series about sort of awakening at night or later in the morning when you really want to be asleep and it's just a struggle to get back, and as you noted there, he was saying they often come in under-slept and my suspicion is that they're probably getting sleep at the front end in part because they're heavily medicated but self-medicating in terms of helping-

    10. AHAndrew Huberman1:12:15

        Right.

    11. MWMatt Walker1:12:15

        ... their sleep. But then of course because they are asleep, they can't continue to medicate so which part of sleep is fragile? It's those morning hours and therefore if you have something that is a compensatory tool that is not going to be the trigger of saying, "Just get back into bed, get under those sheets and sleep." You know, sleep doesn't work like that. Sleep is not something that we do. Sleep is something that arrives to us, with us. And if it's not, you can't force it and it's not... It's a little bit like someone's name, in fact, quite the opposite that the harder you try to remember, the further you push sleep away and when you stop, it all of a sudden comes back. But I love this idea of inserting something like that as a compensatory tool and that's why I think you and I have discussed, um, openly here in fact on this series, at some point we're going to collaborate and we're going to look to see exactly what is happening...... electrically at high fidelity mapping inside of the brain when we are going through these liminal states, and what is the benefit of that? Is it a very similar benefit for sleep? And it's fascinating because it's possible that what we find at the level of the brain is that it's not sleep-like, it's something else like. Maybe it's just a liminal state-like. And what's also interesting is that it provides seemingly many of the benefits of sleep, but it's not sleep. In other words, you can arrive at the same destination of mental and physical health through two different routes, one thing called sleep, one thing called these liminal states. Or they both operate on the same highway in terms of mechanistic transaction benefits. There's so much that we need- (laughs)

    12. AHAndrew Huberman1:14:01

        Yeah. Well, I-

    13. MWMatt Walker1:14:02

        ... we could stay here all, all night and all day, hopefully not all night.

    14. AHAndrew Huberman1:14:05

        Well, well, we will absolutely do those studies and, um, because I think that people are in desperate need of zero cost tools to try and, um, access the, the, the replenishment and recovery that comes from sleep, and when sleep is available to us, when we can access it, that's going to be the best option, there's no question. But then some of these tools, um, in theory and in practice provide a, a portal to get better at sleeping as well. So, yeah, so that's-

    15. MWMatt Walker1:14:33

        I was going to say, one of the other things I'd, I'd be fascinated for us to do is not just look at that model of what happens in the morning, but can we use that for people who have the opposite insomnia problem, which is that I can't fall asleep. And we spoke about this in a previous episode of tools and techniques and methods to help you fall asleep. Could this be one of them where you s- just start to help move yourself into this liminal state, you take the stress off! One of the things I hear so much at the center when people come in and they say, "I just always struggle to sleep." And you go into depth, and it's because they- their mind starts to Rolodex through that anxiety of what I need to do and what I should do, but also then the f- later it gets and the, the absent their sleep becomes, the more stressed they get, not just about the next day, the more stressed that they get about this thing called not being able to fall asleep. And if there's something, a practice that you've taught someone that says, "That's okay, I know this place and I know this situation, and there's a tool I have, and it's called (pauses) this a liminal state." And if you were to train people on that sort of, that method, is it a way that they finally can then cast themselves off and it's the, it's the bridge, not necessarily just between despair and hope, but the bridge between wakefulness and sleep. So put it at the back end, at the end of the day, rather than the front end.

    16. AHAndrew Huberman1:16:06

        Uh, a lot for us to discover there, and, um, you know, at risk of, of, uh, being hyperbolic, I mean, what would be more useful than a zero cost non-pharmacologic tool for people to get, um, the rest and restoration they need, and to get better at getting the ultimate form of rest and restoration, which is sleep?

    17. MWMatt Walker1:16:26

        Yeah. And it, you know, I love the paradox of it, that non-sleep deep rest allows you to go into sleep deep rest.

    18. AHAndrew Huberman1:16:35

        Right. (laughs)

    19. MWMatt Walker1:16:36

        (laughs)

    20. AHAndrew Huberman1:16:36

        It is, after all, a transition or liminal state. Maybe this will become the, the stage before stage one of sleep. Who knows?

    21. MWMatt Walker1:16:42

        Yeah. Yeah.

    22. AHAndrew Huberman1:16:42

        Who knows?

    23. MWMatt Walker1:16:42

        Redefine our staging criteria.

    24. AHAndrew Huberman1:16:44

        That's right.

14. 1:16:46 – 1:23:50

    Anxiety & Sleep, Mood vs. Emotions

    1. AHAndrew Huberman1:16:46

       That's right. Okay, so speaking of challenges, sleeping because of one's concern, AKA anxiety about the importance of sleep, what about the relationship between sleep and anxiety? Meaning...

    2. MWMatt Walker1:16:58

       Mm-hmm.

    3. AHAndrew Huberman1:16:59

       ... many people in the world experience low level anxiety or have a low threshold to what could be a full-blown anxiety or panic attack, but more often than not is this feeling of being tired and wired or, um, having a, uh, a quick, uh, you know, pre-pulse startle as we call it in our business-

    4. MWMatt Walker1:17:18

       Mm-hmm.

    5. AHAndrew Huberman1:17:18

       ... uh, nerd speak for, um, you know, kind of a reactive, um, to input, uh, anxiety. And I don't think there's any clean definition between anxiety, stress, um, and PTSD. These run along a continuum and they braid together-

    6. MWMatt Walker1:17:33

       That's right and PTSD is an anxiety disorder-

    7. AHAndrew Huberman1:17:35

       Right.

    8. MWMatt Walker1:17:35

       ... it's one of many.

    9. AHAndrew Huberman1:17:35

       Right. They, these things braid together in a way that it would be a waste of our time to try and disentangle those. Um, but many people have anxiety that is anywhere from minor to debilitating, um, but that is separate from PTSD, although people with PTSD can have anxiety. So, what do we know about the relationship between sleep and anxiety? And perhaps we could frame this in the context of the QQRT. You know, um, I'll just toss out a question that perhaps highlights what I mean. Is it possible that somebody's getting eight hours of sleep a night, which for them meets their quantity requirement in the, um, the quality is relatively high, but it's not as high as it could be because the regularity and timing of their sleep isn't great. Is that person going to be more prone to anxiety than somebody who's really matched to their chronotype and is still getting enough sleep?

    10. MWMatt Walker1:18:29

        No one's done the head to head comparison where you kind of do the, how I'm gonna do, the Coke, Pepsi, Dr. Pepper, Sprite (laughs) QQRT-

    11. AHAndrew Huberman1:18:39

        Uh-huh.

    12. MWMatt Walker1:18:39

        ... challenge between all of those. What we do know is that if you look at each one independently, QQRT, quantity, quality, regularity, timing, if any one of those is off, it's very difficult not to see a coexisting anxiety disorder or increase in anxiety or a mood disorder. And I think, to me, anxiety is part of that class, of a broader class, that I would call mood disorders. It's relevant that we make that distinction, at least in my eyes, and I know some people may disagree, because mood and anxiety are different than emotions.... and many of us clump them together. The way I think about the difference is the following: timescale. Emotions are short, punctate events that usually last anywhere from seconds to, to many minutes. Mood states, however, like anxiety or depression, those operate on a slightly different timescale, from minutes to hours to months to years. And so it's very unlikely that we can experience an emotional reaction that, from a sort of a chronometry point of view, lasts for two years. But you can certainly see someone who has a mood state abnormality of depression, that lasts for several years, or who has been chronically anxious for several years. And I'll come back to why I think that distinction is, is relevant for a second. To your point, though, about the relationship with sleep, here again it's a very strong bidirectional relationship, and I would say that probably in the last eight or nine years, we've been doing a considerable amount of work in sleep and anxiety rather than just sleep and bo- basic emotional reactivity. What we found is it's very strongly bidirectional, that if you have anxiety, it's very difficult to sleep, and if you are having difficulty sleeping, it's very likely that you will increase your anxiety. But before we really unpacked that, we started with a, a very basic study, m- similar to those that we've described. We took a group of people, and we were very careful to make sure that they had, um, completely normative levels of anxiety. They showed no signs of an anxiety-related disorder. And by the way, anxiety disorders are, it seems, one of if not the most common of all psychiatric conditions, just to put it in context for people listening. And these individuals, no signs of anxiety disorders whatsoever. They were normative. And then we had them go through a full night of sleep, or we then sleep-deprived them, and the next day, we were measuring their anxiety, and in those people who were sleep-deprived, we were actually measuring the level of anxiety every hour. So we could almost get this time-lapse photography of what happened to their anxiety state as it unfolded across the sleep deprivation period. It wasn't a linear response, that the more and more hours that you were awake beyond 16, the more exponential that rise in anxiety became. So it wasn't simply a linear dose-response curve. It was an exponential, meaning that there was this hockey-shaped swing up. And in fact, by the next morning, compared to when you'd had a full night of sleep, those individuals were so anxious that almost 50% of the participants in that group who had no signs of anxiety before had a level of anxiety that was so strong that they would reach the diagnostic threshold for having an anxiety disorder. And that was simply by way of the absence of sleep. But again, that brought me back to this notion of, this is a good experimental tool for us scientists to understand what is the benefit of sleep when it's present and the absence of sleep when it's not by taking sleep completely out of the equation by way of total deprivation. But of course that's not real life. So we did a slightly different study. Here, what we did was we tracked individuals essentially in the wild, as it were, just going about their daily lives, and we had different sleep tracking monitor, uh, monitoring equipment on them. So we were tracking their sleep from one night to the next to the next to the next, and from one day to the next to the next, we were tracking their level of anxiety. And what we found here was that even small perturbations in their sleep from one night to the next to the next accurately predicted their increase or decrease in their anxiety from one day to the next to the next. What was the critical ingredient here? Well, in the first experiment, I'd essentially manipulated both quantity and quality, the two QQs of the QQRT. I'd removed the quantity of sleep, and also they had no quality of sleep. Why? Because they had no quantity of sleep.

15. 1:23:50 – 1:28:51

    Deep Non-REM Sleep & Anxiety, Sleep Quality

    1. MWMatt Walker1:23:50

       But when we looked at that day-to-day-to-day, night-to-night-to-night study, it wasn't quantity that was the best predictor. It wasn't shortening of quantity that determined next-day increases in anxiety. It was quality. The worse the quality was night-to-night-to-night, the worse their anxiety became. So that started to lead us to think a lot more about, what is it regarding the quality of sleep that seemed to offer, when it was present, what I would describe as an anxiolytic benefit? In other words, it's lessening anxiety. A lack of sleep is an anxiogenic. It's going to produce anxiety. What in sleep is anxiolytic? We started off with a hypothesis that was profoundly incorrect. We thought, well, for emotions, which are these short bursts of, um, of affective state, it was REM sleep that seemed to be the principal ingredient. Well, wouldn't that be the case for mood states? Well, here with anxiety, it wasn't. It was deep non-REM sleep, and we couldn't get away from it. And so what we found was that when we looked at their sleep in the laboratory and asked what was predictive from the night before? So we measure your anxiety the night before and then we measure it the next morning, and basically we calculate a change score. Has your anxiety the next morning increased, stayed the same or decreased? And then we correlate that with the different stages. And what we found was that...... the electrical quality of your deep non-REM sleep was very much predictive of your dissipation of anxiety overnight. And this helped me realize, "Gosh, it's much more complex." These are beautiful surprises you get from research when you, you ha- y- like, y- you have this hypothesis and you look at, you see REM sleep, no signal of predictive relationship with anxiety, and I say, of course, 'cause I'm s- idiotic, "Rerun the analysis, just go back to raw data and..." You know, the REM sleep s- signal was so strong. Rerun the analysis, and you get exactly the same result, it's deep non-REM sleep. Great. Okay. Then what is that deep non-REM sleep doing to help dissipate the anxiety? But here again was a commonality with emotion, what we found is that the greater the amount of deep non-REM sleep, the greater the re-engagement of your frontal lobe was the next day, and that was predicting the dissipation of your anxiety the next morning. So we really started to understand this sort of critical bi-directional relationship, but it was a very complex one. That, yes, anxiety can disrupt your sleep, and yes, uh, disrupted sleep can predict your next day anxiety, but it wasn't the same stage of sleep that we thought before. It was the, the opposite. It was deep non-REM sleep. What we've come to realize is that deep non-REM sleep in part seems to be almost shifting you from that sympathetic state d- over to the parasympathetic state. It seems to engage that nice rest and digest. It seems to reduce your heart rate. It seems to drop levels of cortisol. And we think that perhaps is a resetting brain body, literally an embodied mechanism, by way of deep non-REM sleep helping you just relieve that anxiety pressure. So it does come back to your question which is, yes, quantity if I manipulate it, quality if I manipulate it, regularity or timing, manipulate any one of those, I can change your anxiety. But the story coming through here, if anything, was that it wasn't quantity, it was quality. I told you that from one night to the next to the next, the quality of your sleep that we are measuring was predictive of your anxiety, and then when we bring you into the laboratory and we look at the electrical activity of your brain. I also mentioned in that episode on, the first episode, another way we measure quality is not just subjectively what's going on or objectively what is the efficiency of your sleep, is it filled with lots of awakenings, which was the measure that we used in the day-to-day study and night-to-night study, but we looked at the electrical quality of your sleep. Once again, it was quality that was predicting it. It's something about getting good continuous sleep that is replete with this deep non-REM electrical brain activity that provides an anxiolytic benefit to your brain the next day. And I think it's strategic, 'cause so many of us deal with anxiety, and some of us would prefer not to necessarily be on medication or even look to that. Well, here again is a strategic tool. Think about your sleep. It really does seem to be a buffer for anxiety.

16. 1:28:51 – 1:34:56

    Tool: Improve Deep Non-REM Sleep, Temperature; Alcohol

    1. MWMatt Walker1:28:51

    2. AHAndrew Huberman1:28:52

       Along those lines, maybe you can just recap a few of the things covered in previous episodes that are known to improve the quality and quantity of deep non-REM sleep. Um, I can think of a couple but, um, uh, you're the expert here. Um, so if y-

    3. MWMatt Walker1:29:09

       Let's not rush to judgment on that one.

    4. AHAndrew Huberman1:29:10

       (laughs) Well-

    5. MWMatt Walker1:29:11

       (laughs)

    6. AHAndrew Huberman1:29:11

       ... uh, I think it's an established fact, uh, which is why you're here. Um, so let's, um, perhaps list a few of those off in the domains of, you know, exercise, temperature, et cetera. What, what, what would you place in the... You know, is there a top three, like three greatest hits for, uh-

    7. MWMatt Walker1:29:26

       (laughs)

    8. AHAndrew Huberman1:29:27

       ... for improving deep non-REM sleep for, uh, because of its important relationship to anxiety management or reducing anxiety?

    9. MWMatt Walker1:29:36

       I think there are. The first thing I would tell you is that regularity is going to be key here. When you are giving your brain the signals of regularity, it understands exactly how to instigate that, that deep sleep.

    10. AHAndrew Huberman1:29:51

        Mm-hmm.

    11. MWMatt Walker1:29:52

        And that's one of the two qualitative measures of s- sleep that I spoke about. So QQ, the quality, the second Q I spoke about, it's regarding the continuity of your sleep and the electrical quality of your sleep. Regularity is probably best for the continuity of your sleep. If you're very irregular with the timing of your sleep, your brain almost doesn't know, you know, "Are we on? Are we off? Are we on? Are we off?" And your sleep can become quite fragmented because it's confused based on regularity. When you give it regularity, sleep starts to become more stable. More stable means that it's less likely to be littered with awakenings, meaning that it's better quality of sleep. In terms of electrical quality of sleep, we did mention this, um, in a prior episode when we spoke about sort of food and exercise, exercise seems to be one of those things that's very good at improving the quality of your deep sleep, and here I'm talking about the electrical quality of your deep sleep. Try to make sure that you're physically active to a degree and, and I think this is a protocol and I think it's a meaningful protocol, but to go so to the extreme where I would say, "You need to do at least 32 and a half minutes on a spin bike at this wattage," or, you know, we can't prescribe quite at that point s- you know, scientific prescription, not medical. And so I would say exercise is one. Then we spoke about another which was temperature.... and we said that getting your bedroom cool seems to be a way to promote the increase in deep sleep. So these are two dos, which is get regular, get cool. The don'ts, we've already spoken a little bit about two. One of the things that I probably didn't mention enough with alcohol, not only does it seem to compromise your rapid eye movement sleep, but it will fragment your sleep. It will make your sleep more unstable. And an indirect consequence of that is alcohol is going to be in highest concentrations in your system after drinking in the evening with sleep in the first four to five hours. Now, that depends on how quickly you metabolize it and how much you've had, but let's assume some degree of standardization. In other words, I said that alcohol will not just block your REM sleep, it will fragment your sleep. It makes your sleep more vulnerable to you waking up. Well, you're especially vulnerable in the first four or so hours, because that's when alcohol concentration is highest in your system, and therefore, the first four hours can also fall prey to the greatest culling of your sleep quality. And if you're removing or restricting some of that quality in the first four hours, what type of sleep are you principally restricting? You're restricting deep sleep because we've said deep sleep comes in the first half, dream sleep, REM sleep in the second half. So don'ts would be try to stay away from, you know, excessive alcohol in the evening. We also know that alcohol is associated with longer term chronic anxiety, and the tragedy is that it's often used as a way to blunt the anxiety because alcohol is a sedative and it can help just alleviate, take, you know, take the edge off. But it's a short term, quote unquote, win for a long term loss 'cause overall, it will increase anxiety levels. So I would say those are some dos and perhaps a don't if you want to try to optimize your sleep quality, including the integrity of your sleep and also the electrical quality of your sleep.

Episode duration: 2:15:13