GUEST SERIES | Dr. Matt Walker: Using Sleep to Improve Learning, Creativity & Memory

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: 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's episode marks the fourth in our six-episode series all about sleep, with expert guest Dr. Matthew Walker. During today's episode, we discuss sleep and learning, as well as the impact of sleep and the specific stages of sleep on creativity and memory. We talk about when and how long to sleep relative to different bouts of learning, as well as the role of naps in consolidating information that you are trying to learn. We discuss the science and protocols of sleep as it relates to both cognitive learning and motor learning, and the mechanism by which sleep encodes memories. As with the previous episodes in this series, today's episode includes information about the biology of sleep, as well as practical tools, that is protocols, in which you can use sleep to improve your learning, memory, and creativity. 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 Helix Sleep. Helix Sleep makes mattresses and pillows that are customized to your unique sleep needs. It's abundantly clear that sleep is the foundation of mental health, physical health, and performance. When we're getting enough quality sleep, everything in life goes so much better, and when we are not getting enough quality sleep, everything in life is that much more challenging. Now, one of the key things to getting a great night's sleep is to have the appropriate mattress. Everyone, however, has slightly different needs in terms of what would be the optimal mattress for them. Helix understands that people have unique sleep needs, and they've designed a brief two-minute quiz that asks you questions like, "Do you sleep on your back, your side, or your stomach? Do you tend to run hot or cold during the night?" Or maybe you don't know the answers to those questions. If you go to the Helix site and take that brief quiz, they'll match you to a mattress that's optimal for you. For me, it turned out to be the Dusk, D-U-S-K mattress. It's not too hard, not too soft, and I sleep so much better on my Helix mattress than on any other type of mattress I've used before. So if you're interested in upgrading your mattress, go to helixsleep.com/huberman, take their brief two-minute sleep quiz, and they'll match you to a customized mattress for you, and you'll get up to $350 off any mattress order and two free pillows. Again, that's helixsleep.com/huberman to save up to $350 off and two free pillows. Today's episode is also brought to us by Whoop. Whoop is a fitness wearable device that tracks your daily activity and sleep, but also goes beyond that by providing real-time feedback on how to adjust your training and sleep schedule to perform better. I've been working with Whoop on their scientific advisory council to try and help advance Whoop's mission of unlocking human performance. As a Whoop user, I've experienced the health benefits of their technology firsthand for sleep tracking, for monitoring other features of my physiology, and for giving me a lot of feedback about metrics within my brain and body that tell me how hard I should train or not train, and basically point to the things that I'm doing correctly and incorrectly in my daily life that I can adjust using protocols, some of which are actually within the Whoop app. Given that many of us have goals such as improving our sleep, building better habits, or just focusing more on our overall health, Whoop is one of the tools that can really help you get personalized data, recommendations, and coaching toward your overall health. In addition to being one of the most accurate sleep trackers in the world, Whoop allows you to recover more quickly and fully from physical exercise and other kinds of stress, and thereby to train more effectively and sleep better. If you're interested in trying Whoop, you can go to join.whoop.com/huberman today to get your first month free. Again, that's join.whoop.com/huberman. Today's episode is also brought to us by Waking Up. The Waking Up app is a meditation app that offers hundreds of guided meditations, mindfulness trainings, yoga nidra sessions, and more. I started meditating over 30 years ago. At that time, there wasn't very much science on meditation. But by now, we know that there's a lot of strong science supporting the fact that a daily meditation practice can improve mood, focus, and alertness, and can reduce stress and improve sleep and overall health. One thing that I and many others have noticed is that while meditation is excellent for buffering stress, it's oftentimes during periods of stress that we let our meditation practice go. The Waking Up app overcomes this by offering meditations of different durations, so they have some longer ones of 30 to 60 minutes, but also some much briefer ones, 10, five, and even one-minute meditations that are known to be effective. So, no matter how busy or stressed you get, you always make time for your meditation practice. The fact that they have lots of different types of meditations and yoga nidra sessions and non-sleep deep rest protocols also makes sure that your meditations are kept fresh and interesting. You never get bored of them. I personally use the Waking Up app to do a five to ten minute meditation or a non-sleep deep rest protocol, which is similar to yoga nidra, each and every day. And if I miss a day, I try and double up the amount of time that I do NSDR, yoga nidra, or meditation the following day. Yoga nidra and non-sleep deep rest protocols can be done essentially any time of day in order to restore mental and physical vigor. I'll sometimes do one first thing in the morning if I wake up and I feel I didn't get quite enough sleep the previous night. You can also do yoga nidra or NSDR in the middle of the night if you wake up and you're having trouble falling back asleep. Sometimes they will allow you to fall back asleep, and if they don't, you'll still feel more refreshed than you would have had you been tossing and turning and worrying about not getting sleep. So NSDR and yoga nidra are terrific for both restoring mental and physical vigor and potentially for restoring sleep that you otherwise would have missed. If you'd like to try the Waking Up app, you can go to wakingup.com/huberman to get a free 30-day trial. Again, that's wakingup.com/huberman. And now for my conversation with Dr. Matthew Walker. Dr. Walker.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Dr. Huberman.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Welcome back. We have covered a lot of material. First episode of this series, you gave us an overview of sleep and some actionable items about sleep Then in the second episode, you gave us far more actionable items of how to think about one's sleep in a way that leads to very concrete decisions about controlling light, temperature, when to sleep, and then some really in-depth advanced tools-

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Yeah

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: ... or protocols, as we call them. And then in the third episode, we talked about caffeine and napping, and some other things that people can do to really supercharge their alertness through sleep augmentation in the daytime. And today, we're going to talk about sleep, learning and memory, and a topic that I know everybody is very interested in, creativity.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Indeed. Resplendent pleasure to be back on the show. Thank you for having me.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Yeah, absolutely. So I think nowadays most people understand that there's some relationship between sleep and learning. But I think it would still be a good idea for us to zoom out a bit and establish what that relationship is. I think most people are familiar with being exposed to some new material, cognitive material, physical skill material, and not being able to learn it right away, but then having a few days in between, and then all of a sudden, voilà.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Yeah.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: The skill has been embedded it seems. But not obvious in that scenario is that sleep is perhaps the pivotal event that allowed the learning process to take place. So how do you think about sleep as it relates to learning and memory?

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: I think I've conceptualized it in three different stages or three different buckets of a benefit. The first is that we need sleep before learning to prepare your brain to initially imprint and lay those memory traces down. But then you need to sleep after learning to take those sort of freshly minted memories and then save them and cement them into the brain so that you don't lose them. The third domain is that sleep will then take those new memories that you've been learning, and it will start to collide them with all of this back catalog of information that you've already got stored in your brain, and it updates the iOS of your informational systems so that then you come back the next day, and you have a better abled ability to understand how the world works. In other words, the difference between knowledge, which is learning the facts, and wisdom, which is knowing what it all means when you put it together. That's the third category. And why is that beneficial? Because it provides you with creative insights. And so we will perhaps just double-click on each of those three, and I can expand them because the data behind them is utterly fascinating. As you said, I think many people subjectively have a sense that sleep helps me with my memory in some way. But in what way? And for people, I think one of the things that you do here is not just protocols, but you help explain the conceptual understanding or the conceptual mechanisms underlying the reasons for all of these protocols, and I would love to dive into detail.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Yeah. So let's do that. Let's talk about this business of sleeping before learning, essentially establishing a milieu within the brain that is-

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Mm

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: ... optimal for learning. What is that about neurochemically at the level of circuits, and what is the evidence that providing some, I don't know, additional sleep or just adequate sleep prior to the exposure to the new material-

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Yeah

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: ... can be beneficial?

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Yeah, I love that word, that optimal milieu, and it beautifully describes what we've found. We started off asking a very simple question at my sleep center, is pulling the all-nighter a wise idea? So we took a group of perfectly healthy, smart individuals, and we assigned them to one of two experimental groups, a sleep group and a sleep deprivation group. And both of those groups went through those two different protocols, and then the next day after sleep or after no sleep, we put them inside of a brain scanner, and we had them try and learn a whole list of new facts as we were taking snapshots of brain activity. And then we tested them to see how effective that learning had been. When we looked at the group that had had a full night of sleep, they had incredibly efficient learning capacity. So in other words, they had learned and imprinted that information initially very well. When we looked at the sleep deprivation group, not so much. In fact, there was a 40% deficit in the ability of the brain to make new memories without sleep. And we've used lots of different types. We've replicated that now. We've had visual information. We've had textbook-like information. And the range is somewhere between 20% to 40%. I find that, by the way, striking, and we can come back to this based on what we are seeing in our educational systems right now. There is this paucity of sleep because of this model of early school start times, and I'll explain exactly what's happened there and what we've been doing to try to change that. But coming back to those two groups, the sleep group and the sleep deprivation group, what was going on, as you said, inside of the brain that would help us understand why they couldn't learn or at least couldn't learn effectively? And the structure that we focused on is one you've spoken about before called the hippocampus And you have one on the left side and the right side of your brain. It looks like a long cigar that runs down the left and right side of your brain. And people listening can think of the hippocampus almost like the informational inbox of your brain. It's very good at receiving new memory files and then holding onto them. And when we looked at that structure and its activity during learning in the sleep group, they had wonderful, powerful activation of the hippocampus, as if it was gobbling up all of that new information into the inbox. When we looked at the sleep deprivation group, however, we couldn't find any significant signal whatsoever. So it was almost as though sleep deprivation had shut down the memory inbox, and any new incoming files, they were just being bounced. You couldn't effectively commit new experiences to memory. And then subsequent studies that were not done by us, but looking at animal models, they were looking at how able the synapses are in that memory structure, the hippocampus, how capable those synapses are for building new connections. And the synapses are just those connections between neurons, and we think that part of the way that we make memories is by strengthening the connection in the memory circuit itself. And what they found was that when they restricted the sleep of these rats or the mice, that part of the brain became very stubborn. It just wouldn't form those new synaptic connections. It's something that we call synaptic plasticity. So we started to understand this was the bad that happened when you take sleep away. But let's come back to that control group that I said got a full night of sleep. Exactly what is it about sleep when you do get it that seems to support and promote your learning ability? So we decided to do another different study. Instead of manipulating sleep by dialing it down, we instead tried to dial it up by way of a daytime nap. And again, we took two groups, and we had them initially learn, again, a huge amount of factual information. They learned it over and over and over again. And then we brought them back six hours later at 6:00 PM, and now we had them learn a whole new set of information. And after each one of those fresh, novel learning sessions, we tested them to see how effective that learning had been again. One of those groups spent that six hours of time awake, doing just relaxing activities. The other group was able to obtain a 90-minute nap, and we used that 90-minute nap to allow them to go through a full sort of average cycle to get some non-REM and to get some REM. And what was interesting is that when we tested the group that remained awake later that following day, their learning capacity had declined. But in the nap group, it seemed to restore the brain's capacity to learn, and you didn't get that decline in memory. In fact, if anything, you got a little boost. And the difference between those two is about 20%, which is quite a nice benefit.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Yeah, not trivial.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Not trivial at all. And then we said, okay, well, if sleep is doing something, what is it about that sleep? So we unpacked the physiology of sleep and the different stages of sleep that we discussed in the first episode. And what we found was that it was the non-rapid eye movement sleep, or the non-REM sleep, and particularly those sleep spindles, those short bursts of electrical activity that we have discussed before, that seemed to predict how restored and refreshed your learning ability was. And the best way that I've been thinking about this in terms of sleep restoring or refreshing your encoding ability, and it's a crass analogy, and I don't mean to make a direct brain-to-computer analogy, but think of that hippocampus almost like a USB stick.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Mm-hmm.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: That's very good during the day at going around and grabbing new files, but it has a limited storage capacity. And what sleep was doing seemed to be shifting those memories from the USB stick of your hippocampus over up to the cortex, which you can think of almost like your hard drive, a much bigger storage capacity. And by way of doing that, when you woke up after the nap or after a full night of sleep, you had this cleared out USB stick. So what could you do? You could go around and start acquiring all these new files again. So that started to teach us a little bit about why sleep before learning is critical, but also mechanistically how sleep is doing this remarkable work of memory restoration. We then wanted to say, well, can we translate this out into the real world? And I think there are two regions that we've moved this work out into. One is education, one is medicine and Alzheimer's disease. But the education piece was very interesting. In the United States, I think the last time I checked, the average school start time is somewhere around 7:30, 7:45.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Sounds about right.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: And if you think about that for 7:30 school start times, school buses will begin leaving around 5:30, 5:45 in the morning.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Mm-hmm.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: That means that some kids are having to wake up at 5:00 AM, maybe even earlier. This is lunacy when you think about it. And there's a great study in Edna, I hope I'm pronouncing that correct, Edna, which is a small suburb, or it sits in a small suburb outside of Minneapolis in Minnesota. And they shifted their school start times from 7:25 to 8:30 in the morning. And then they wanted to ask what is the consequence of that on the academic performance of their students. And the metric that they used in these teenagers that they were focusing on was something called the SAT score, which is a score I had to learn when I first came to the United States. Is a critical assessment test that will largely determine which university you go to. And they did an analysis, which was clever. They focused on the top 10% performing students, which you could argue those are the ones that are closest to the ceiling performance and the hardest to expect any benefit from sleep. So in the year before they made the time change, the average score of those top 10% performing students was 1,288, which turns out to be a pretty good SAT score. The following year after they made the time change, the average score for that top 10% was 1,500. That difference is non-trivial, and it will change exactly where those individuals will go to university in terms of the tier of the university and likely change the trajectory of their lives-

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Amazing

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: ... as a consequence. Now, some people have argued that data, in terms of its source and its reliability may not have necessarily been accurate, but now we've got very consistent data. When you start school times later, academic grades improve, psychological and psychiatric problems decrease, truancy rates decrease. But something else happened in that story of later school start times that we didn't expect, which was that the life expectancy of students increased. And you think, "Well, hang on a second. How do you determine that?" The number one cause of death in teenagers 16 to 18 is actually not suicide. Turns out to be second. It's road traffic accidents. And here, sleep matters enormously. There was another great example from Teton County in Wyoming, and they shifted their school start times from I think it was 7:35 in the morning to 8:55. And the only thing more remarkable than the extra one hour of sleep those kids reported getting was the drop in car accidents. That following year, there was a 70% reduction in car crashes in that age range of 16 to 18.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: What time are they getting out of school?

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Well, they will probably be ejected out of school, that's another interesting part, by the way, maybe around 4:30. And people have said, "Well, look, all of this idea of later school start times, it means that it's going to cost us more because you've got to change the school bus system," and they've argued pushback against that. And I would say probably two things. First, I know it's difficult, and I'm not saying it's an easy problem to do. It's a complex problem. And I'm sympathetic to that, but I think we've put people on the Moon, and so I suspect that we can also solve the problem of early school start times. The other component of that is what are we doing as educators? If our goal as educators is truly to educate and not risk lives in the process, then we are failing our children in a most spectacular manner with this incessant model of early school start times. And if you look at the data, it's very clear. When sleep is abundant, minds flourish, and when it's not, they don't. And so that's the reason why myself and a whole group of sleep scientists, we started to try to create a movement for later school start times, and we got this bill passed, firstly in California, and we got it on the governor's desk at the time. It was Governor Brown. And unfortunately, he didn't sign it into law. Then when the organization changed and Governor Newsom came in as governor of California, we got the bill back on his desk, and he did sign it. And then, the next state to go was New York. They started to put in legislation for recommendations for later school start times. I think Florida is about to fall as well in that regard. So there's gradual movement happening, but it's hard-fought, and it's problematic. I still think that it's impossible to deny that data. It was an interesting thing. I remember when I was a professor back at Harvard, we were doing this work on sleep and learning. And it was sort of published in these sort of kindly, I don't know how we did it, but in nice journals. And they said, "Okay, based on the media traction, would you write an editorial for the Harvard newspaper?" Which was called "The Harvard Crimson." And I said, "I'd love to." So at first I thought, I'm just going to write a straight piece about sleep and memory and why it's important. Then I realized, no, there's a better opportunity because teaching there, and you know this as well as I do, there is this bizarre system where we teach for an entire semester, and then we end load the semester full of exams in this stressful two-week period. And what do you think is going to happen? They're not going to sleep, especially at a time when they're trying to cram information. So-

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Right, especially in college where you don't actually have the material four weeks before, so there's not really the option to learn it in advance.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: No.

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Everything about university to me was about getting a bunch of information and needing to incorporate it very quickly and then move to the next item.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: Right. Next item. And then all of a sudden, there's this cataclysmic moment at the end of the semester, and you are supposed to regurgitate this by cramming everything into your brain-

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Right

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: ... in this sleepless two-week period. So rather than saying, look, the students need to change their behavior, they need to understand this is a problem, it's not their fault I said, "It's us as educators and administrators, we have created a system that forces them to undergo deliberate sleep deprivation, and we are educating them amnesic quite literally."

Andrew Huberman develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Andrew Huberman: Mm-hmm.

Dr. Matthew Walker develops this part of the discussion through the following account. The point is grounded in the episode's own evidence and qualifications: Dr. Matthew Walker: So I put this editorial out. It received a rather Baltic, if not Arctic, response, and that was the last editorial I was ever invited to write for the newspaper. But you've got to say your piece.