AMA #18: Cold Therapy Advice, Skin Health Tips, Motivation, Learning Strategies & More

Welcome to the Huberman Lab podcast, where we discuss science and science-based tools for everyday life. Hi, everyone. I'm delighted to kick off this premium subscriber AMA. And today I have some great announcements to make, including the fact that we have now expanded our SciComm, that is the parent company of the Huberman Lab podcast, as some of you know, we've expanded our SciComm Huberman Lab podcast philanthropy to support great, exciting science that is going to directly relate to mental health, physical health, and performance tools in the very near future. And we've been able to do that thanks to all of you because we use a significant portion of the funds from the premium channel subscribers to support exciting work on humans. So, these are laboratories working on questions such as improving mental health, physical health, and performance from a variety of approaches at all major universities. And we've supported work at Stanford, Columbia University, University of Oregon coming up. We're actually supporting some programs related to student training and teaching in the realm of neuroscience and happiness. So, some really exciting, groundbreaking areas, all made possible thanks to you and the fact that we now have three dollar-for-dollar matches from exceptional donors. When we started this premium subscription model to support science, we had one, still have this one absolutely spectacular dollar-for-dollar donor match from the Tiny Foundation, and now two others have joined in. So, for every dollar that is used from the premium channel to support these exciting areas of research, we now have three dollars being donated to match that dollar. So, we essentially have a 4x what we would otherwise give in terms of supporting exciting new research on humans in various laboratories at Stanford and elsewhere. I'll just touch on a few areas that we are supporting going forward. Um this is a not an exhaustive list, but for instance, we are supporting some exciting work using deliberate heat exposure to treat symptoms of depression. A really interesting and forward-looking approach to treating depression, for which there's already some really exciting preliminary results. We are going to be supporting work on goal setting um, at New York University. This is really exciting work. Many, many people struggle with goal setting and habit formation that can serve them in their career and in their personal life and fitness goals, health goals. This work directly relates to that. In other words, you're supporting that work. We are also supporting work on immune system nervous system interactions. This is an area of science that's now really progressing quickly that explores how especially in babies and kids and young adults, but also in more mature adults, interactions between the brain and nervous system and the immune system can cause all sorts of interesting susceptibilities, but also patterns of resilience in people that do specific things as it relates to supporting their immune system. So, thanks to you and these dollar-for-dollar matching donors, we are able together, but mainly thanks to you, to support these exciting areas of human research. And as the data come in, we are going to relay what the new findings are and of course translate those where appropriate to protocols for improving mental health, physical health, and performance. So, I want to extend a deep, deep, deep message of gratitude to you for supporting science, for supporting new research, and for supporting the evolution of new data to serve humanity. Thank you ever so much. Okay, so without further ado, let's get to answering your questions about mental health, physical health, and performance. The first question uh, comes from Robert. And the question is, "Is there any way to repair thinning skin as we age? I'm 77 years old and in the the few years, the skin on my arms has gotten noticeably thinner. Thank you. Well, thank you for this question. It's a very timely question given that we just had a solo episode. I did a solo episode about skin health and appearance on the podcast. I should mention that that episode was reviewed by a derm oncologist. I consulted with different dermatologists prior to that episode. And my general sense is that it's been received very well. There are few areas within the skin health and appearance uh field that are of uh controversy, mainly around sunscreens. I'll just go on record saying that it's very clear that excessive sun exposure will age skin more rapidly. Okay? That's just categorically true. Okay? So, if anyone's debating that, um you know, there's an issue there, right? There shouldn't be any debate about that. It's absolutely true that sunscreen can help, and there are sort of three major forms of sunscreen. This relates to how to protect skin from thinning. One is a physical barrier. Pretty much nobody disputes a physical barrier. A hat, a long-sleeved shirt, long pants, etc. However, those don't always cover all the areas of the body that need sun protection, such as the ears, the back of the neck, portions of the face, and so forth. When it comes to sunscreens, sometimes called sunblocks, I think there's general agreement that the sunscreens, and I'll use sunscreen and sunblock interchangeably, that are mineral-based, that is inorganic, meaning that the active ingredients are either zinc oxide or titanium dioxide or some combination of those up to a concentration of 25% are generally deemed safe by most all dermatologists. Now, there are some people who will point out that there's some controversy around certain forms of titanium dioxide. The evidence for that, however, is not conclusive. I would say that if you're really, really concerned about any of that, then just stick with a pure zinc oxide formula up to 25%. Why would people not use zinc oxide formulas? Well, they tend to be kind of pasty, and they don't spread on very easily compared to some other sunscreen formulas. Sunscreen that are quote and quote chemical based, okay, everyone will say well everything is a chemical. Yes, but they're chemical based they use a different approach to blocking or reflecting or absorbing you UV rays. Those do indeed have some controversy around them. There are few studies in which very large amounts of those chemical containing sunscreens, these are chemicals like oxybenzone etc. are applied to the skin and they do make it into general circulation. Um they do blood draws, they see that some of these chemicals can be endocrine disruptors leading some people to believe that chemical based or sunscreens that contain some of these chemicals are to be avoided. Now, I want to be very clear on my stance which is if you need sun protection and the choice is either to use those types of sunscreens occasionally versus no sun protection, I would say probably better to just use them. But if you are picking a sunscreen aka sunblock where you are going to be using it all summer or very frequently, well in that case probably best to go with a mineral based sunscreen because you'll be doing more frequent exposure application, okay? And then of course there are people that will argue that the chemical based sunscreens are in fact fine and if that's your threshold um meaning that there isn't enough conclusive evidence that they're problematic then that's fine. So those are the three general categories, but yes sun will damage the skin. That doesn't mean you shouldn't get any sun uh exposure to your skin. Turns out that generating D of course um getting your circadian rhythms right, hormone production etc. actually requires some exposure to sunlight. You just don't want to do it during the highest UV index portions of the day like the middle of the day. Um you don't want to burn. However, and please note this you do not have to burn in order to put yourself at a greater risk for skin cancer. So, you know, avoid burns but avoid excessive sun exposure for you as well. Now, back to Robert's question, the skin is thinning. Why is it thinning? Well, as we get older, the composition of the proteins in skin, and there are many different proteins, but in particular the collagen and elastins start to either mutate or weaken. Um there could be less production of these. The skin sometimes loses moisture as well, and the basic solution to this is the following. We know that sun protection will help. We also know, and I covered this in the episode, that there's some evidence, okay? It's I would say it's moderate evidence. It's not extremely strong. It's not weak, that ingestion of collagen proteins, believe it or not, can improve skin elasticity and the appearance of smoothness and plumpness as it's subjectively rated in these studies. You might ask yourself, well, how is that? Is it Is it that you ingest collagen? And by the way, people typically do this at um dosages of anywhere from You'll see as low as 5 g per day, but as high as 30 g per day of collagen protein. Typically, there's some vitamin C in there as well, which seems to help its absorption or utilization. And they will observe in these studies over time some improved elasticity, appearance of smoothness, and plumpness of the skin. So, should you ingest collagen protein? Well, the results are, again, statistically significant, but they're not overwhelming in the sense that um you're not going to reverse uh all the thinning um and kind of the what appears to be a little kind of local sagging of the skin completely um by ingesting collagen, but it can help. Collagen can be ingested through things like bone broth. Um by the way, collagen is is a composition of not just skin, but of tendon and ligaments and things of that sort. Um typically, people will get their collagen in powdered form. It's relatively inexpensive. There are a lot of different forms of this from fish, from animal sources. Um there are some plant-based sources. Um there It's a little unclear whether or not those are as good. But in any event, 5 to 30 g, typically 15 to 30 g in the most of the studies, does seem to be moderately effective in improving skin elasticity, plumpness, and appearance of smoothness. Okay, so that's one one area. The other area where there's some interesting research is red light exposure. So, uh red light exposure is an interesting one because, of course, in sunlight we have full spectrum light, right? If you ever put a prism and um out and you get a light beam through it, you know, you get the rainbow, right? It includes red. There are long wavelengths, aka red, wavelengths of light. I I pause as I say red wavelengths because they're actually long wavelengths of light that appear red. And it has been shown that light panels that are emitting red light or near infrared light, or typically both, can also improve skin appearance if done for about 10 to 15 minutes per day, maybe 5 days per week minimum, over the course of a few months. Again, the results in those studies are statistically significant in many of those studies. And I would place them in kind of the moderate result, meaning it's not a striking result, but you could imagine combining red light with the collagen, so you start to get um perhaps a synergistic effect, but those studies combining them have not have not been done. It does seem that one of the best, that is dermatologist-supported ways to improve skin appearance, is to ingest a retinoid. Um now, these are prescription drugs. The retinoids um do require that, you know, you work with a qualified dermatologist. They require that you stay out of the sun for some period of time because they can increase uh sensitivity to the to the sun, but they will improve collagen composition, and that's from the inside out. So, and by the way, there are also some um different uh supplements that one can take that can protect your skin so that you don't have to put sunscreen on. It's actually the extract of a vine. I did not cover that on the skin health and appearance episode, but we very soon have a guest, uh Dr. Teo Soleimani, who is an expert dermatologist oncologist trained at Stanford and Harvard and UCLA, who is going to talk about the use of essentially sun guarding by the ingestion of certain compounds that change the chemical composition of the skin from the inside. So, it's very interesting. He also added another tool for improving skin appearance, and this is true for the face and for the arms, etc., is the use of laser resurfacing. Now, this is not a cosmetic procedure as much as it is a procedure to remove the very top epidermal layer, the very very superficial layer of of dead keratinocytes and other cells of the skin, excuse me, as a means to reduce cancer risk. Okay, so he's a derm oncologist. It does have the consequence of making skin look quite a bit younger. So, it does work. And like anything in the realm of kind of laser resurfacing and things of that sort, it does require a period of peeling, of staying out of sunlight because and being really strict about that because the skin is more sensitive in the immediate days and even week after the the laser resurfacing. It was kind of remarkable for me to learn that this laser resurfacing and the retinoids are very well supported by dermatologists as a preventative measure for certain forms, not all forms, but certain forms of skin cancers, and that they can dramatically improve the appearance of skin, that is to make it look more youthful. So, certainly that would work on the arms as well. So, we've got We're talking about collagen, red light, retinoids, laser resurfacing by a qualified dermatologist or derm oncologist, ideally. And the reason I I emphasize the derm part is there are a lot of people who do kind of plastic and cosmetic work on skin who are probably very qualified, and then there's probably some who are not as qualified, and there can be some real issues raised by using excessive laser power and things of that sort. This is something I also touched on in the episode. So, those are the four major ones, and then of course eating a diet that's low inflammatory, so limiting fried and um highly processed foods, of course. Um making sure that you're getting enough essential fatty acids in the form of either supplementing or ingesting fatty fish oils. Um all of these sorts of things, fruits and vegetables, fiber, all the all all the sorts of things that support healthy skin internally. Some directly, some indirectly by virtue of the gut microbiome. So, um I think that's probably a sufficient answer. Ah, I I will add one last thing uh for your question, Robert. It's very clear that the appearance of skin is also very supported um by hydration and moisture. So, put applying a regular uh moisturizer, a high-quality moisturizer, regularly. Pick a non-fragranced moisturizer regularly to the to the arms. That will help as well. And then there's some um more uh aggressive approaches that I'll talk about with uh Dr. Sulimani. Um things like hyaluronic acid and things of that sort that can help with the kind of plumpness or moisture of the skin, but we'll hold off um for that episode, which comes out in a few weeks. So, thanks again for your question. I um I like to think that um those are some um actionable uh tools, and then depending on people's disposable income, time, and energy they want to devote to this, uh you could go with the zero-cost one, the moderate-cost one, or or um the combination of all of them if if you're able to. Okay, the next question comes from Jen Shaw. How How cold does the water need to be for cold therapy to be effective? This is a great question, especially since at least in the northern hemisphere, it's summer, and people are doing cold plunges more, cold showers. Such an effective tool for shifting the state of your mind. You know, the any debate about deliberate cold exposure to me um that centers around metabolism, or you know, how long the dopamine increase lasts is is kind of a trivial one in my in my um uh in my estimation, because what do we know for sure? We know that deliberate cold exposure is very, very low cost, or even cost saving if you use a cold shower because you're saving on the heating bill. We know that um if you can afford a cold plunge or access a safe river or stream or cold plunge, great. What do we know it does? It's changes your state. It shifts your state. It makes you more alert, not just while you're in there, but in the minutes and certainly up to an hour or more afterwards. And let's face it, rarely does it feel good getting in. Sometimes it feels good being in it uh because you're very, very warm before you got in it. Maybe you came from a run or from the sauna. But it always feels great getting out and you always feel much better afterwards, provided you get the right stimulus, which is really what this question's about. So, what is the right stimulus? How cold? Cold enough that you feel a bit uncomfortable and you want to get out, but you can safely stay in and you stay in for a little bit longer. Now, I know that sounds vague, but there has never been a systematic study of exactly how long to stay in at a given temperature at a given time of day. And why do I say at a given time of day? Well, try doing a cold shower first thing in the morning. It can be pretty rough, pretty jarring. Try doing it at night when you're tired, far bigger barrier to getting in that cold shower or cold plunge, unless you are particularly warm because you exited the sauna or exceptionally motivated. So, the point is to make the water just cold enough that you would kind of retract from it, that you don't want to be in it, but not so that it's like icy burn, so cold that it burns. This is my my opinion. I like to do deliberate cold exposure in the following way. I don't even do it for time, I do it for what I call walls. So, if you're having a hard time even persuading yourself to get in the thing, well then that's one wall you need to get over. And then if you get over that wall, which hopefully you do, you get in and you start to breathe very quickly, just know that if it's very cold, you'll breathe quickly. And after about 20 seconds, your ability to think clearly will come back online. Okay, that's right about the time that most people say that their hands or feet hurt. Okay, I do recommend putting your hands under. It's not necessary, but hands and feet under. If you're in the shower getting your body as small as possible, sometimes people will huddle in the shower. If you really want to make it uncomfortable, you can, you know, raise your your arms and get it in your armpits, which is especially cold. But in any case, it should be uncomfortable. And then you should stay in till you adapt to that. Like, okay, so maybe that's 30 seconds, maybe it's 10 seconds, maybe it's a minute. And then I suggest getting out at that point. So I would say anywhere from 1 to 3 minutes for most people, maybe 30 seconds if you're really experiencing a lot of mental barriers to getting in there. And it should be just cold enough that you don't want to be in there, that you want to get out, but that you can stay in for that 1 to 3 minutes safely. Why do I say this? Well, if you get into very, very cold water, like 30° Fahrenheit water, and you're and really hyperventilating, you do run the risk of hypothermia, you run the risk of putting your, you know, your cardiovascular system into shock. I mean, there is a real danger to these things. And by the way, you should never, ever, ever do any kind of breath work prior to getting into deliberate cold. Okay, prior to getting into very cold water, because if you're doing a lot of exhaling, you're blowing off a lot of carbon dioxide, that will limit your gasp reflex, and there have been people who have done, you know, cyclic hyperventilation, deep breathing, then gone into water, and they didn't realize that they needed to breathe. They didn't get that gasp reflex early enough, and unfortunately, they blacked out and died. So that's very serious. So what do I recommend in terms of cold water? Great to have somebody there. Ideally, you have somebody there with you who's not in the water with you, who can monitor you. If you're talking about cold shower or cold plunge, and you're talking about, okay, should I do it at 40° or 45° Fahrenheit or 50°? Well, put your hand in, and then ask yourself, on a scale of 1 to 10, how eager am I to get in? If it's 10, well, then it's probably a little too warm, or maybe you're just highly motivated. If it's a five or a six and you're kind of feeling some resistance, great, provided it's not so cold that it's dangerous. So, for me, the typical temperature, if you just want me to throw one out there, is somewhere between 45 and 50° and a few of my friends who really like it extra cold or like a an ice bath will say, "Oh, that's weak." Well, that's what works for me. I never like the cold, I love getting out of it. Sometimes I like being in there after a little while, but I never like getting into it. I much prefer heat in the sauna. And while we're here, I'll just um mention how hot for the sauna. Again, same thing. Hot enough that you feel a little uncomfortable, but not so hot that you put yourself in danger. And here, we really have to emphasize danger because doesn't take much of a temperature increase to overheat the brain. So, for me, I'm pretty heat tolerant, so I'll put the traditional sauna, not infrared sauna, but traditional sauna to about 210 and I'll last about 10 to 20 minutes in there maximum and then I'll go into the cold plunge and back and forth. Okay? So, if you're going to do the cold plunge for the first time, maybe start at 55, 60° and stay in a little longer. If you're going to um be more experienced with this and you're more cold tolerant, try 45, 50. And then if you're really aggressive and you want to try um getting down into the uh you know, low 40s or so, high 30s, well, then make sure you have somebody there and make sure that you um don't force yourself to do something that's going to cause um tissue damage or cardiovascular damage. Cold is a very potent stimulus and you should go with the minimum effective dose, but you don't have to obsess over the difference between 58° and 56° or 46 and 48. I think subjective feel is going to help. Just make sure that you build in some safeties so that you can adjust quickly, stay out of danger. No deep breathing prior to getting in there. Now, some of you might be asking, "Well, what about deep breathing while I'm in there? That's how I calm myself down." That's fine, but no emphasizing the exhales to blow off carbon dioxide, certainly no submerging yourself intentionally, okay? So, be safe, have fun with it. Deliberate cold exposure, I think is a wonderful tool for increasing alertness, not just while you're in there, but when you get out. In fact, that's the best part, if you ask me, is getting out. All right, next question is from Katie. It's about self-motivation. Do you have any suggestions or steps to self-motivate to start a new routine? I do. I do, I do, I do. First of all, be very careful who you announce and what you announce to people in terms of starting a new routine, unless they are going to really be on you about accountability. In general, talking to people about our goals, less effective in my opinion, and then there's some research to support this, than just simply making the decision, writing it down, simple, you know, old school like me, 8 1/2 by 11 paper, write down what the goal is, give yourself a check for each day that you do it or the times of day that you do it. Sometimes signing your signature as if you have a contract with yourself can help. These are all different tricks. Some people will say, "Should you reward yourself for completing something?" Sure. "Should you scare yourself into doing something?" Sure, there's data to support that also. I covered this in the episode with Emily Balcetis and about goal seeking and habits that I did a solo episode. We have a newsletter on this. Here's the deal. There are going to be multiple barriers to starting a new routine. I do believe in incremental approaches to these things. Right now, I'm working on some bonus chapters of my book and while I'm pretty motivated person, I'm an excited to share that information with the world. I must say that setting aside time to do these bonus chapters has been challenging because I've got a lot else going on. So, rather than tell people that I'm doing that, I actually have a contract with myself that I sign each time I complete anywhere from a 10- to 60-minute writing block. So, a contract with yourself can really help. I think it's far more valuable than stating to the world what you're going to do. I don't know why that tends to work, um but we know why stating to the world what you're going to do often wears off because typically, and this reflects both good and bad things about human behavior and psychology, typically people will support you by saying, "Great, you're going to do great. The book's going to be great." or "Your new exercise program is going to be great. You're going to do" and they're just supporting you, supporting you, supporting you, and that support turns out to be sufficient to create this mindset like that you could do it at any point where you've got the support you need. Sometimes a little bit of additional friction, what Tim Ferriss would call fear setting, is a good idea. You think about worst outcomes if you don't do the thing, but let's face it, you can't lie to yourself and believe it. So, if you know that not doing the thing isn't going to markedly change your life for the worse, well, in that case, you need some additional support. You need some additional motivation. So, you could use all sorts of tools and protocols like a cold shower to increase epinephrine, adrenaline, and dopamine and get more motivated and do something. You could, and I think this is probably the best tool anyone could apply, which would be to put away your phone, turn it off, put it in the other room. I now have a box for my phone that I've dedicated to keeping my phone in when I'm busy doing, uh, other types of work for which the presence of the phone would be an an intrusion. It would limit my work output. I do think that the contract with self is going to be the best way. You say, "I am going to do 30 minutes of whatever, uh, resistance training, yeah, three times a week." and then you're going to sign off by the end of the week and when you complete each one, that's your reward to yourself that you were accountable. There's no external reward. Why do I say this? The work itself should become the reward. We know this from all the work on growth mindset that we've talked about, Carol Dweck's wonderful work and David Yeager's wonderful work. He was a guest on the podcast. I've done solo episodes about their work about growth mindset. That ultimately the work becoming the reward is how you're going to sustain motivation over time. So, when you sign off that you did the work and that's the reward, well, then there's a this kind of, um, cyclical relationship between, uh, what you've promised yourself you would do, what you did, and rewarding yourself for the work. No additional external reward, the work becomes the reward. So, I like the idea of being a bit of a what we would call closed-loop system on motivation rather than going out and seeking excessive support from others. And I say this not to isolate. I encourage healthy relationships, et cetera. But, if we start seeking external validation or pressure in order to do what we know we want to do or would love to be able to do without external support, we limit ourselves. And when that support isn't there, we tend to you know, be far less productive and move toward our goals far less well. So, it's an internal process of reshaping your psychology. There's also some deeper psychology around this stuff of, you know, agency and what you feel you deserve. You know, you deserve. I'll tell you this cuz I believe everyone deserves to be able to better themselves through these kinds of self-directed actions. And I also like the idea of a closed loop because you can be really honest with yourself at the end of a week, you know, did you do your three sessions? Did you sign off three times? Keeping some of that reward system and validation internal really helps you become stronger, also to be able to support other people if they need your support. Whereas, if you have a committee of people that you rely on, are you you know, that you need to hear from, you need their support in order to be motivated, well, that can be great. Coaches can be great and support systems are wonderful. I don't think it's nearly as effective as being your own committee. You're your own chair and secretary in this case and member of your own committee. And then, of course, seek social support and reinforcement for other areas of your life that you need. And be a source of social support, but also encourage people to be in this kind of self cyclical loop of motivation and to really uh the principles of growth mindset, which is really what we're talking about. Make the effort the reward. Okay. Um I'm going to take a sip of uh tea here. Lou asks, "What can you do if you're not getting enough rapid eye movement sleep? What are the consequences?" Okay, so to remind everybody, rapid eye movement sleep is more and rich towards the end of the night. It differs from slow wave sleep or deep sleep. Tends to be dream rich sleep. The dreams tend to be more elaborate. You also dream during deep sleep, um during slow wave sleep, but uh your dreams are far more emotionally laden during rapid eye movement sleep, more vivid, etc. And rapid eye movement sleep is associated with learning. So, getting enough rapid eye movement sleep, especially on the first night after trying to learn something, is important. Rapid eye movement sleep is also important for removing the emotional load of previous day and previous days' experiences. So, it's its own form of trauma therapy. During rapid eye movement sleep, your body is essentially incapable of releasing adrenaline, so you can have these very intense emotional experiences in your mind without adrenaline in your body. You're actually paralyzed during rapid eye movement sleep. It's a healthy paralysis. Sleep atonia, it's called. How do you get more REM sleep? Well, one of the best ways to get more REM sleep is to simply add anywhere from 10 minutes to 30 minutes to your sleep schedule. Adding that 10 to 30 minutes in the morning. Most people can't do that, however. Another way to increase the amount of rapid eye movement sleep that you get is to get a bigger surge of epinephrine, of adrenaline in the early day prior to that sleep. So, this is a great reason to do deliberate cold exposure in your shower in the morning. Um you could also get it through exercise. So, exercising early in the morning, and then we're talking about the rapid eye movement sleep that occurs the very next that that same night. Okay, so we're talking about a Monday morning where you exercise and get deliberate cold exposure. By the way, it is true that if you do deliberate cold exposure after resistance training, you can limit some of the strength and hypertrophy increases or adaptations, but at other times it seems to be fine. And there is zero evidence that taking a cold shower after resistance training is going to limit strength or hypertrophy adaptations. So you don't have to be too paranoid about deliberate cold exposure. In fact, I think the best recommendation I can make about deliberate cold exposure is neither be too paranoid nor too obsessive about it. Um so spiking your adrenaline a bit in the early part of the day with exercise and or deliberate cold exposure can help get more rapid eye movement sleep later that night. Sleeping in a bit, even 10 minutes more going back to sleep. This is a case for hitting the snooze. You go back to sleep, maybe even two or three times. Um oh of course better to just sleep the whole way through until uh maximum long night is achieved, long night of sleep that is. If you wake up and you're not rested enough or if you're looking at your sleep score and you don't see enough rapid eye movement sleep, the other thing you can do is a non-sleep deep rest protocol, which by the way Matt Walker's laboratory and I are um gearing up to do some studies on a non-sleep deep rest and how it impacts the brain specifically as opposed and this has been done in other studies but not with modern methods in a while. Um so we're excited about that. So do a 10 to 30 minute or 10 or 20 minute uh non-sleep deep rest protocol. Those are easy to find. I have zero cost ones that are on YouTube. You simply put NSDR Huberman. Um there's a 10-minute one, a 20-minute one. Uh we have them in Spotify format. There's actually a link on the hubermanlab.com webpage um that links out to audio format so that you don't have to go on to YouTube. If you don't want to do that, you can download that script from Spotify and that way you have it in your phone. You don't need to even have internet access. So if you're camping or you're out of internet access, um you can still do that non-sleep deep rest. And then if you prefer a female voice, Kelly Boys, b o y s, um, has some wonderful NSDR and Yoga Nidra scripts, uh, on YouTube and has her own, um, uh, she also is on the Waking Up app doing NSDR and Yoga Nidra. So, I would do that first thing in the morning to get a bit more REM-like rest is what we'll we'll call it until the data are in. REM-like rest puts the brain into this very interesting state with body completely still, right? Similar to sleep atonia that you observe in REM sleep, and mind active, very similar to REM sleep. This is actually our hypothesis, which is that non-sleep-deep-rest mimics rapid eye movement sleep, but that hypothesis still needs to be tested formally, and Dr. Walker and I are going to do that. So, that's another way to get more REM sleep. The other way, and this is, um, kind of a tongue-in-cheek answer, is if you don't get enough REM sleep on one night, you can be sure that if you allow yourself sufficient sleep the next night, you'll get more REM sleep than you normally would anyway had you slept well the previous night. What does all that mean? Means that there's something called the REM sleep rebound. If you don't sleep enough or you don't get enough REM sleep on, say, Monday night, Tuesday night when you go to sleep, provided you didn't blitz your system with caffeine, you're not ingesting, um, anything that would disrupt your REM sleep such as caffeine late in the day, well, or alcohol, which will disrupt REM sleep dramatically, well, then you will get more REM sleep on Tuesday night. Okay, there's a comp there's a REM compensation. Anyone that's tracked their sleep, uh, has observed this. Uh, so that's, uh, another way. Right now, there's no clear pharmacology to induce more REM sleep, unfortunately. Um, there are some tools to increase, uh, slow wave sleep, deep sleep pharmacologically. Um, some of the growth hormone secretagogues that are in common peptides, uh, will do that, but right now there doesn't seem to be any pharmacology directed specifically at increasing REM sleep. There are a few um these go by brand names like Corvivec and things like that that are thought to do this, but it's still somewhat uh debated as to whether or not they specifically increase REM sleep. Okay. Danielle says, "The top three most impactful things schools could do to raise student capacity for learning." What a great question. Well, I'll add a fourth because I don't want to um I don't want to try and wriggle out of the question by just saying sleep again, but I think um trying to get kids to sleep enough is going to be key. So, that means off phones and iPads in the middle of the night. That means starting school a little bit later. I don't know if that's ever going to work, but that would be a marvelous thing for learning because as you know or we all should know or remember neuroplasticity and learning is triggered by focused attention, which is supported by having slept well the night before, but the actual rewiring of neural connections occurs when? It occurs during sleep. It occurs during deep sleep and rapid eye movement sleep. That's when the reorganization of neural connections occurs, the strengthening of particular synapses, the weakening of other synapses, and there's a small small small perhaps infinitesimally small percentage of neuroplasticity that is the consequence of the addition of new neurons. So, most neuroplasticity is not that. Most neuroplasticity is the reorganization of existing neural connections. But, nonetheless that happens during sleep. So, getting kids to sleep enough, nap enough, sleep late if they need to is actually a great thing, but who knows if schools will change their protocols. What else can we do? What can schools do? Well, I'm a big fan as you know of non-sleep deep rest. Wouldn't it be wonderful if in every school it started the day with a 5-minute meditation or non-sleep deep rest where kids would do some quiet focused breathing, bringing their attention back to their breathing, bringing their attention back to the spot just before behind their forehead um just before beginning a learning session. Why? Why? Is it about mysticism? No. Is it about trying to understand consciousness? No. It's about a study done by Wendy Suzuki's laboratory at New York University. She's their current Dean of uh letters and sciences as far as I know. She's a neuroscientist. She has a spectacular record in the field of neuroscience and psychology. And her laboratory showed that even a very brief meditation session in that particular study it was about 13 minutes per day can significantly improve working memory, which is the ability to keep information online in one's mind active. Um it can increase other forms of memory. It can increase focus. It can decrease stress. And it is a zero-cost tool. So, I think unfortunately, we think of meditation as a mystical tool to explore consciousness, and it can be. But if you think about it, exercise can also be an ultra marathon to run 242 miles or something to win a trophy. Um or it can be something to improve cardiovascular health. So, similarly, meditation is just a perceptual exercise. I think that if kids learn that they can bring their perception internally to what we call interoception as opposed to looking at things externally, exteroception, understand that they have some control, some regulation over their focus and attention, bringing their attention back to them, to interoception whenever it drifts, well, then they get better at focus over time, and it improves learning in the long term, but also in the bout of learning that they go into immediately after. So, you know, if I had a magic wand, every classroom would begin a session of learning with 5 minutes or maybe even 3 minutes of what is typically known as third eye or focused meditation Um with no interest in mysticism, pure interest in improving the bout of learning. Uh I think another thing that uh schools should include uh to increase capacity for learning is they should include micro gaps. So, we know that if you take gaps in information um delivery. So, for instance, if I were to just pause now and then continue. It's a seems like kind of a an odd interruption. And then every once in a while at random introduce a short 10-second pause or so. What do we know happens? We know, based on now a number of different really high-quality papers that have looked at musical learning, mathematical learning, concept learning, physical skill learning, that those little micro gaps allow for very rapid replay of the information that's relevant um if for whatever reason in reverse in the brain very quickly within the hippocampus and the neocortex areas of the brain critical for encoding and storage of memories. And these little micro gaps and the rapid replay of the information one is trying to learn at 20 to 30 times the normal rate increases the number of repetitions. You're basically getting 30 repetitions for doing nothing. This is exactly what happens in what? In rapid eye movement sleep. When you learn something, like maybe you learn something today in our discussion thus far, and you go to sleep at night, there's a very strong chance that if we were to record from your brain, we would see that the same areas of your brain that were active during specific portions of this discussion, which arguably is more of a lecture than a discussion, but those brain areas would repeat at 20 to 30 times speed within a very compressed time, and then you'd go back to a different pattern of brain activity. What is going on? Well, in rapid eye movement sleep, the brain is rehearsing, it's generating repetitions of certain forms of behavior and certain forms of learning of cognitive information at high speed you're generating more repetitions and this is critical for the learning process. We know this from animal studies. We now know this from human studies as well. So, if in the classroom teachers would just say, "Okay, we just finished discussing, I don't know, the cell cycle or the Krebs cycle. Now let's take a moment." And students are not checking their phone at that time or reviewing the material at that time. They just got 20 to 30 repetitions of And by the way, at a subconscious level, they're not aware of it, of the material they had just been exposed to. And so, you introduce introduce these, excuse me, at random. Um you could do anywhere from one to five of these per hour. You could do as many as 10 per hour. You're just introducing these brief micro rest intervals. There's a beautiful literature to support this. And the third thing, it's very important, is I think it's very, very clear that physical activity, in particular cardiovascular training, um any kind of physical activity, running, jogging, swimming, etc., is going to facilitate learning, especially if the learning is done immediately after that activity. That's right, if the learning is done immediately after the activity, and that's probably related to the increase in the various catecholamines, dopamine, epinephrine, and norepinephrine associated with physical activity, the making coding of new memories, encoding of new information more readily accessible. So, this is a call for um including PE class in um or even just some basic movement, um even walks or things of that sort. We can look at this through the other lens and say, "What are the worst things for learning?" Terrible sleep, being delivered information like through a fire hose with no pauses, and forgive me if from time to time I tend to do that. Maybe I should start introducing micro gaps into the podcast, but you can always just pause it, go back to it. I feel like real life provides that. There is the strong, strong incentive for including some physical movement each day. And then I I if we were going to include another one, we'd say that kids and teachers should have a discussion about optimal learning protocols. They should understand where their thresholds are, after which their attention falls off. There's really no point in trying to learn information if you're not focused on what you're trying to learn. And then there's all discussion to be had about caffeine, there's a whole discussion to be had about nutrition as it relates to maintaining alertness throughout the day. Anyone that's ever gone into a lecture on a college campus or a high school or elementary school even after lunch, you'll see that people's brains are just kind of idling there in the background. It's the rare student that's wrapped with attention even after a big lunch, even after running around outside. So, structuring of the day properly is essential. And of course, get that sleep at night. Okay. Um Alec, could you share your thoughts on how shilajit might influence cognitive function and physical health, specifically its impact to boost testosterone? I get a lot of questions about shilajit. Shilajit is a mineral pitch from the Himalayas. There are a lot of fake versions out there, but the authentic versions are basically This is stuff that um uh basically, they take soil and and grasses and a bunch of things and they mash it down and they take the extract and they create this stuff called shilajit, which sometimes is sold as a thick paste, kind of a tar-like paste. Sometimes it's in capsules. What do we know about shilajit? Shilajit um contains minerals that are thought to augment some hormone pathways, and that's why people have argued and it's marketed that shilajit increases vitality. It's been argued that shilajit can increase testosterone, maybe estrogen as well. There are actually a few studies on this that are covered at examine.com. I'm going to bring up one just now. Um this week I can do so a little gap effect here if there's a pause. Um there is some data, not a ton, but there's some data that support the use of shilajit for um testosterone increase, but I would place it on the low end of the effectiveness scale in terms of things to increase testosterone. And then of course the real question is are you getting enough authentic shilajit to really have an effect? The dosage on this is very mysterious. In other words, I personally wouldn't place shilajit high on any list of ways to generate hormone support. There are far better ways. I mean the best ways of course are to make sure that your body fat percentage is neither too high nor too low. Okay? The you know, people who are overweight, who are obese, who lose body fat will improve their hormone profiles dramatically. However, people who are already very lean, who get excessively lean, you can disrupt testosterone levels dramatically. And by the way, anytime there's a discussion about testosterone, I want to remind that both men and women have testosterone. It's important in both men and women. Yes, it's related to libido, but having sufficiently high levels of estrogen in both men and women is also critical for libido. People that take drugs like anastrozole to disrupt the aromatase conversion of testosterone into estrogen can sometimes find themselves with reduced libido. And that's because estrogen is critical for libido in men and women as is testosterone. So it's all about the ratios. Going back to shilajit, let's look at at the human effect matrix on shilajit. There is one study here with 60 participants that sites a small increase, small but statistically significant increase in follicle stimulating hormone FSH, which in females is critical, in males is critical. And the extent of of the increase is just very small. So it's not it's not clear that it would be worth taking shilajit given the risks and and the cost. It depends on how aggressive you are in trying to increase testosterone. Certainly there are other ways. Sperm quality, one study showing a small improvement in sperm quality. One study of 60 participants showing a small increase in testosterone. So and then of course there's a bunch of other things that have been looked at. The perhaps most impressive effect is a reduction in um some LDLs, but again, even though I say the most impressive, it's still a small effect. So, I wouldn't place shilajit high on the list of supplements to consider. Always, always, always, before talking about supplements, you want to get your nutrition right. I've talked about how to do this. You want to be exercising, but not overtraining. You want to do both resistance training and cardiovascular training, maybe on the same day or different days, whatever your schedule allows. You want to make sure you get enough sleep at night. If you want to increase your testosterone significantly, get an extra 30 to 60 minutes of sleep each night. Even a 20-minute increase in rapid eye movement sleep is going to serve your testosterone far better than taking shilajit. Will taking shilajit increase your vitality? You know, probably increase your energy a bit. You might increase libido a bit. You have to ask yourself, is it transient? Is that effect transient? Is it directly related to testosterone increases? Probably not. It's probably directly related to follicle-stimulating hormone increases. And for women who have a menstrual cycle that is you know, obviously going to lead to different constellations of hormones, markedly different constellations of hormones, such as follicle-stimulating hormone, estrogen, progestins, etc., different times throughout the cycle, taking something like shilajit, because it can stimulate FSH release, can potentially disrupt that. If you're a male who's doing everything else, like you're exercising, you're sleeping well, your your nutrition is is locked in, you are you're taking creatine and fish oil, you're taking care of your gut microbiome, and you want to experiment with shilajit, well, by all means, um find a a reliable source of shilajit. They are out there. Just look for one that has some testing for authenticity. And then you'll you're likely to be able to see within about a week or so if it leads to a significant increase in vitality, libido, whatever it is that you're seeking. But I wouldn't place shilajit high on the list of things to pursue. And I will also say, having tried shilajit, um it's pretty messy. It's hard to get the dosaging right in the tar form. Um the capsules make it a little bit easier. Um if you wanted to explore other ways to augment testosterone that um have a bit more data to support them, I would say things like tonga ali, which may have its effects on increasing libido in both men and women by virtue of increasing testosterone or maybe free testosterone more likely. It's an increase in luteinizing hormone in that case, which is upstream of testosterone. So, this can all get into some pretty um uh extended discussions about biochemical pathways and hormone pathways. I did this on the episode about optimizing testosterone and estrogen as a solo episode that I also covered with Dr. Kyle Gillette and with Dr. Peter Attia. By the way, if you go to hubermanlab.com and you put in any combination of search items, if you put for instance shilajit testosterone, it will take you to the timestamp that covers that. If you put um tonga ali testosterone or libido tonga ali, it will take you to the timestamps across different episodes directly to those timestamps so that you don't have to listen to entire episodes or go searching for this information. It's all there. We also have an AI engine at hubermanlab.com that allows you to do searches on this sort of thing. But of course, I'm happy to talk to you about it as well. I'm delighted to. So again, if you have the budget and you're somebody who likes to experiment, maybe shilajit is the the right thing for you. Uh find a good brand. It shouldn't be hard to distinguish the the real uh the real brands. Um they always have a a label of authentication on there. And if you're going to already be doing everything else right behaviorally and you want to explore supplementation for improving testosterone, vitality, etc., then I would say don't start with shilajit. You'd probably be best off starting with something like tonga ali, maybe fadogia. I've talked about these things previously. Okay. Um Let's see. Um two questions popped up in front of me, so I'll just take the first one. Um Alexander um Alexander, I like the way you spell your name, Alexander. It's unusual. I dig it. Uh what has your process been for the writing of your book? Slow. Uh um I have a a saying that I I say in my lab um or that I have said for many years in doing science when I was a graduate student a postdoc and then in my lab. And by the way, sometimes people ask about this. I still have research funds for human studies. I closed my animal lab focusing mainly on teaching, which I'll be doing again this year. Teaching in the spring. Maybe in the winter as well to undergraduates and um I may get re-involved in some human clinical studies on vision. An area that I've loved for many years. But in any case, there's a saying that I always would reiterate to my students and postdocs, which is I go as fast as I carefully can. Okay, so I believe in a sense of urgency. I like to sit down to write and think, okay, I'm going to go as fast as I carefully can. It's that right balance between urgency and precision. Okay, going fast is rarely good in its own right. Um going too slow isn't good either. So there's that place where I feel like I'm just pushing myself a little bit, but then you have to be careful, right? So as fast as you carefully can. So the process has been slow, but I've been going as fast as I carefully can. Any recommendations on overcoming obstacles and how did you deal with them? Yes, put that phone away. Put in the other room if you have to. Generate accountability measures. Do it. When I used to write grants in my laboratory in San Diego, you can ask my lab. I used to walk in and say, okay, I'm giving my phone to somebody. And if I ask for it back before 5:00 p.m. today, you each get a thousand dollars. And I did not have a thousand dollars to give everyone in my lab. I had a pretty big lab and I didn't have the money. So you may have to create some barriers. And gosh, about an hour and a half in, I think, okay, gosh, I was supposed to respond to this person today. They're going to think that I've dropped off the map. Oh my goodness. And then I'd remember, oh, I have an office phone. If someone really needed to get a hold of me, if it was an emergency, they'd let me know. And if I couldn't be reached that way, someone would find me. I realize for people with kids, etc., this might not be feasible, but if you have to do that, you do that. Set stakes, okay? Give someone a check for an exorbitant amount of money that you can't afford to give away, but that you do have in your bank account. Give them that check and say, you know, if I don't um uh stop writing for the next hour, then um you can tear up the check. Otherwise, you can go cash it. So, you can put some fear in there, but again, as I mentioned earlier, better to generate these um kind of incentives with yourself. So, I like to put my phone away. I like to take about 10 minutes to transition into the writing. And then, I actually set rules for myself. I don't allow myself to get out of the seat even to use the bathroom. It's true. Um I've never gone to the bathroom in my seat, but I resist the temptation to get up until the timer goes off. That's how I did it as an undergraduate. That's how I did it writing grants. That's how I've done it writing fellowships as a graduate student. And that's how I write the book now. Um and I find that after about 20, 30 minutes, I don't want to stand up. I'm super happy. And then, if an interruption comes, then I get frustrated cuz I want to keep writing. So, give it a try. Set some high-stakes incentives for yourself. I mean, don't don't make them too high, but um set some high-stakes incentive. Um thank you for saying looking forward to the book. I appreciate it. Um if you want to buy a pre- a pre-order copy, it's at protocolsbook.com. Um it's there in multiple languages now. I'd uh you know, grateful if you did. On the other hand, if you don't want to buy it or you just want to wait till it comes out, that's fine, too. Um and I'm just grateful that I have the opportunity to put this information into one place that people can access if they like. Mike Torres, and I think this is the last question, right? Are we down to about the last question? Two more? One more? All right, here we go. I'm asking my producer here. Mike, where can I find information from Huberman Lab regarding addictions and recovery? Great great question. I get this a lot. A lot of people struggle with addiction. Addiction is a progressive narrowing of the things that bring you pleasure in ways that can be very disruptive for your life. These can be process addictions, meaning behavioral addictions. These can be substance abuse issues. First of all, I just want to say while I have no formal relationship to them, you know, there are wonderful zero-cost um resources in every city around the world. 12-step communities, go online, look for that. The The meetings and programs that they provide are very useful. Um have proven very useful. Actually, this was explored in a study from Stanford psychiatry a few years ago because there hadn't been a lot of science on those sorts of programs, and the conclusion was they can be very, very useful. Uh in terms of Huberman Lab resources, if you go to hubermanlab.com, put addiction into the search function, it will take you to specific timestamps, mainly of an episode that I did with Dr. Anna Lembke, who is our um director of the dual diagnosis addiction clinic at Stanford, the author of Dopamine Nation, an absolute um virtuoso in terms of the description of the underlying biological mechanisms, mostly surrounding dopamine, um but also the approach to treating and um getting over addictions. You can get over addictions. People get sober from their addictions. It takes time, it takes energy, it takes effort. Um and in every case, it's an incredibly rewarding thing that just makes your life and other people's lives better. So, I highly encourage anyone that's struggling with process addictions or substance abuse addictions or alcohol use disorder or things of that sort to pursue those resources, um both on our website and of course the other resources that I mentioned a few minutes ago. Also, Anna's book Dopamine Nation is a wonderful one. It will allow you to see and understand that these are brain mechanisms that are at play. These are not um It's not a lack of willpower. It's a disruption in neurochemical circuit regulation. And that should give you some um grace and some feelings of ease because what that means is that, while it is not, quote unquote, your fault, it is your responsibility to deal with it, and you can and there are great zero cost resources to do that. So please access those. And then just popped up on my screen it says, "Happy birthday Karen Dingar." I hope I pronounce that correctly. Happy birthday Karen and happy birthday to anyone else whose birthday happens to be today or in the vicinity of today. I guess this is going to be recorded and put out eventually and then it'll be somebody's birthday on every day at some point. But happy birthday Karen. Thank you for being a premium subscriber. Thank you all for tuning in. Thank you to those of you that listen to this at a later time recorded. I really appreciate your questions. I really appreciate your support of Huberman Lab. As I've said many times before it's a labor of love. It continues to be a labor of love. I spend my life, my basically all of my waking life minus some self-care and some care of others and hopefully a bulldog soon, another bulldog soon. Can't wait. I've been looking for bulldogs and there will be another one soon. I don't know his or her name will be but in the absence of tending to those things I'm focusing 98% of my waking life to trying to suss out the best health and science information for you all and get it out to you in formats that are convenient for you, that are useful for you and that you can apply. Also discussions with expert guests. So there are the guest episodes, the solo episodes. There's hubermanlab.com has a lot of resources like the AI engine. Please give that a try if you like. It's basically a AI version of me which is kind of weird to me but it does a pretty good job. I would say it does a very good job of encapsulating a lot of themes. It's a great way to generate your own brief protocols if you want to do that. You can ask it to generate a you know exercise plan based on Huberman Lab protocols or what have you. And then the newsletters I'm assuming most of you already subscribe to but if you would be so kind as to make sure that you follow the podcast by clicking subscribe on YouTube, following the podcast on Apple and Spotify. Just click If you already follow by the way, make sure you don't accidentally unfollow, but if you go click that follow tab, that really helps us. It's zero cost. Give us a five-star review if you think we deserve it or different review if you think we deserve that. I love your comments on YouTube. I do read them all. I really do read them all. I even go and find the hidden comments that get filtered and I read those, too. So, please if you feel inclined, you can support us in that way and most importantly, take the protocols and the information that you think works for you, apply it, discard the protocols and the information that you don't feel is for you, discard it. That's great. And of course, I don't deserve credit for any of these protocols per se, right? These are the product of so much great science and and health studies out there, clinical studies, and I'm just a funnel and a filter, but it is a true pleasure to be able to be that funnel and filter. So, thank you for letting me funnel and filter today's knowledge for you. And as always, thank you for your interest in science.