Huberman LabAccelerate Learning & Increase Cognitive Capacity | Dr. Tommy Wood
EVERY SPOKEN WORD
150 min read · 30,027 words- 0:00 – 4:05
Tommy Wood
- TWDr. Tommy Wood
There's a much more recent study that took, again, older adults and randomized them across three different groups. One was like a low intensity group. Another group basically did kind of zone two type work on a treadmill three times a week. And the third group did, um, a high intensity interval training intervention, which was the Norwegian four by four protocol. So four minutes, uh, 85 to 95% of maximum heart rate. They had a three minute rest in their protocol. They did that four times over.
- AHDr. Andrew Huberman
That was three times a week.
- TWDr. Tommy Wood
Three times a week for six months. That's, that's pretty intense. But what they showed was that that high intensity interval training group, they improved their fitness just as well as the zone two group, interestingly, but they had much better improvements in hippocampal function and maintenance of hippocampal structure on an MRI scan, and they maintained that benefit for five years after the six-month intervention. So they worked really hard for six months, but that, that benefit was maintained for, for a really long period of time.
- AHDr. Andrew Huberman
[Instrumental music] Welcome to the Huberman Lab Podcast, where we 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. My guest today is Dr. Tommy Wood. Dr. Tommy Wood is a medical doctor and neuroscience researcher at the University of Washington in Seattle. He is also the chief science officer of Better Brain, a company that provides free brain health coaching. Tommy is an expert in neuroplasticity and human performance, and how science-based protocols can be used to improve your focus, ability to learn, and skill expression. His work applies to everyone from the novice to the elite expert and for all kinds of skills, cognitive, language skills, athletic and creative endeavors. Today we discuss the brain states that favor learning and importantly, how to get yourself into those states. We also discuss how to get the most from a learning session. For instance, how long that session should last, how many sessions to do per day, and perhaps most importantly, how to tune your mind and body to get better at learning. That's something we don't often hear in the context of learning and neuroplasticity, that our brain circuits for focusing and learning are also capable of plasticity, meaning you can literally get better at getting better. Today we discuss things like flow states and something called a clutch state, which is a seldom mentioned but critical brain state to accelerate learning and performance. In fact, a clutch state is the state that you want to seek to learn and perform at your best. We also discuss how different types of physical exercise from long slow cardio to brief high intensity cardio and different forms of resistance training each open the window for distinct types of neuroplasticity and learning. So this goes way beyond the general discussion about exercise improving your brain. We get really granular about exactly what types of things to do to improve your brain in specific ways. As a career neuroscientist who has worked on and taught neuroplasticity for decades now, it's rare that I encounter someone with as deep knowledge about the real science and application of learning and plasticity as Tommy has. He's also extremely unique because he has a ton of knowledge about new science-based protocols for plasticity, and he's also an athlete, and we discuss that a little bit at the end as well. So today you will hear a lot of information that I am confident you have not heard on this podcast or anywhere else, frankly, about exercise, mental training, nutrition and supplementation, and much more, and how you can leverage each alone and in combination to learn new skills with accelerated speed, precision, and durability over time. I should also mention that Tommy recently released a new book that he wrote entitled The Stimulated Mind: Future-Proof Your Brain From Dementia and Stay Sharp at Any Age. It's an excellent book if you're interested in following up on today's discussion and learning more about how you can make your brain better at any age. 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, today's episode does include sponsors. And now for my discussion with Dr. Tommy Wood. Dr.
- 4:05 – 11:11
Neuroplasticity; Neurogenesis; Synaptic Pruning
- AHDr. Andrew Huberman
Tommy Wood, welcome.
- TWDr. Tommy Wood
So amazed to be here. Thanks so much for having me.
- AHDr. Andrew Huberman
Man, this is my favorite topic in the entire world.
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
What is more interesting than neuroplasticity, right? The brain is so interesting, but its most interesting feature, in my opinion anyway, is that it can change itself.
- TWDr. Tommy Wood
Essentially, that's its core most important function. If it can't do that, literally none of the other functions matter [laughs] , you could, you could argue. And it's something that we have to be able to do right until the end of our, end of our lives.
- AHDr. Andrew Huberman
You have an eclectic research tapestry.
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
All right? Today we're gonna talk about neuroplasticity, what it is, what it isn't, how to access it for men, for women, different ages. And you also are a high performance coach. You're also a competing natural strongman.
- TWDr. Tommy Wood
Uh-huh.
- AHDr. Andrew Huberman
Yeah?
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Uh, so does that mean lifetime no, no gear?
- TWDr. Tommy Wood
Lifetime. Well, it's tested. Uh, I, yeah, lifetime no gear for me personally.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
But it's a drug tested s- uh, version of the strongman sport, so yeah, if you, uh, if you compete in natural strongman, then you, you get tested.
- AHDr. Andrew Huberman
Great. So we'll, we'll talk about that. I'll resist the temptation to talk about your two boxer pups-
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
... 'cause I'm a dog lover. That's a different episode. Neuroplasticity. I know what it means to me. How do you conceptualize it? How do you think people should think about it in terms of wanting to learn things and not forget things?
- TWDr. Tommy Wood
I essentially just think of it as the brain responding to inputs in order for us to then be able to better navigate and survive our environment, and that's why I think it's such a fundamental part of what the brain does. And essentially, every time you learn something, interact with something, remember something, the principles of neuroplasticity are engaged, right? You are making new synapses or strengthening synapses, weakening other synapses. A lot of people don't realize that particularly brain development, but then also the refining of functions in the brain Through neuroplasticity includes the pruning or removal of synapses. Often we think about it's all about growth and new connections, but actually it also involves the refining or removal of, of other connections that aren't needed. That's the, that's a, a massive part of, of brain development in the first place. [inhales] And this is a process that's essentially continuously on- ongoing, and you can think of it as, its, its primary role is so that you can navigate, survive the world around you, and that's through learning skills, through remembering people and things and facts. Um, and where I ... One of the, one of the things that's most interesting to me about neuroplasticity and the way we think about our brains over time is that I think people have, uh, conflated neurogenesis and neuroplasticity.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
So when we're thinking about brain development, we're thinking about, um, then also brain function over, with, with age and either cognitive decline or maintaining cognitive function. [lip smack] We thought that the adult brain was, was fixed, right? Um, or, or then it was fixed and then it lost function, and this goes all the way back to Cajal who said the adult brain is immutable, right? He told us that you got into adulthood, it finished developing, and then it was kind of done. [inhales] He then at other times also said that changes in the connections between neurons could explain learning, and so there he's talking about neuroplasticity, but we, we kind of got this idea that the brain was essentially fixed as an adult and then d- you know, couldn't change anymore. But that can't be true because you still learn and remember things on a daily basis as, as an adult. [inhales] One of the things that I think we've gotten, um, confused about is the fact that the adult brain does not make new neurons in many places, right? Maybe in the olfactory bulbs, in the dentate gyrus, the hippocampus but-
- AHDr. Andrew Huberman
Tiny, tiny number.
- TWDr. Tommy Wood
Yeah, but like compared to the rest of the brain, they're not, you're not really making new cells. [inhales] And so because of that, we thought, well, we can't then grow and adapt or change our brains as adults. [inhales] But just because we have a fixed num- relatively fixed number of cells doesn't mean that we can't change the connections between those cells, and that's happening all the time, and that is, you know, the main principle of neuroplasticity.
- AHDr. Andrew Huberman
Yeah, I like your definition, um, in part because I agree with it-
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
... uh, in, in part because it encapsulates a lot of, uh, things, including, um, helping to clear up this misconception that, you know, we generate new neurons.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
I think the attractiveness of the new neuron idea is just, uh, it's so sticky.
- TWDr. Tommy Wood
Mm.
- 11:11 – 14:33
Aging & Neuroplasticity; Familiar vs Novel Tasks
- AHDr. Andrew Huberman
If you were to tell people, "Look, you want to keep your brain as young as it can possibly be-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... relative to your chronological age, you should" what? [inhales] Like it, it ... So this is a general brain health question-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... but really I'm specifically asking about plasticity.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
And let's make it multiple choice, and then you can add things to it.
- TWDr. Tommy Wood
[laughs] Okay.
- AHDr. Andrew Huberman
You should exercise, so it can be multiple things, and then we'll talk about which types of exercise. You should continue to do the things that you already know how to do.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
And then third option, um, not mutually exclusive with the others of course, is, uh, you should try to do new things that you can't already do.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
Now, I, I still toil with this when I look at the literature on neuroplasticity and aging, right? Like yes, use it or lose it is true.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
But we're also told that novelty and trying things that we're not good at is an essential component of building out brain circuits, continuing to make them function better as we get older. So how do you, how do you think about all of that?
- TWDr. Tommy Wood
I'll partly answer your last question and then maybe give a framework for how I think about it. So when you look at a combination of epidemiological studies and intervention studies in older adults, so everything about maintaining cognitive function later in life, you definitely see that those who continue to engage in hobbies and activities that are cognitively engaging or cognitively demanding, and that can be lectures, that can be, um, volunteering, that can be, you know, reading crosswords, that kind of stuff. Those individuals tend to either have slowed rates of decline or better maintenance of function over time and/or lower rates of dementia. That's of course observational, right? But that's usually people continuing to engage in the things that, you know, they've already been doing, right?
- AHDr. Andrew Huberman
So they're holding onto what they've got.
- TWDr. Tommy Wood
Holding onto what they've got by continuing to do that.
- AHDr. Andrew Huberman
Okay.
- TWDr. Tommy Wood
Now, of course, it could partly be reverse causation because if you're maintaining function, then you will-- you're more likely to continue to do the things that, that you enjoy doing, right? So there's probably-- it probably goes in both di- both directions. However, there's an increasing body of literature that shows that by engaging older adults in novel cognitive activities, you see improvements in function. So that can be language learning, uh, that can be, uh, complex, like coordinative movement or exercise. You see the same things with, um, like musical training, like people learning a, a new musical instrument or learning, um, musical theory, trying to identify different patterns in music. And you see in randomized control trials improvements, particularly in executive function, that seems to be most common across those different interventions.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
But you're seeing, um, improvements in cognitive function with novel cognitive stimuli. Uh, there's a lot of, uh, recent trials that have also used types of brain training, um, things like the POINTER trial that was here in the US, Maintain Your Brain, which is a, a massive online study done in Australia recently, and that's sort of broad cognitive training with like an online cognitive training platform. So again, it's, it's a new, uh, or novel, um, intervention or exposure that seems to provide a stimulus that improves function. So I think both can be or do seem to be important.
- 14:33 – 16:49
Protocols Book; Sponsor: David
- AHDr. Andrew Huberman
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- 16:49 – 21:56
Aging, Training & Processing Speed
- AHDr. Andrew Huberman
Can I ask what, um, for an example of-
- TWDr. Tommy Wood
Hmm
- AHDr. Andrew Huberman
... maybe one or two of the things that were in that large scale trial from Australia? Like, just at a, at a very top contour level, um, older adults, meaning 65 and older, um, are doing what?
- TWDr. Tommy Wood
The Maintain Your Brain, uh, study w- was actually-- It was, um, sort of midlife, kind of, uh, 50s and, 50s and 60s mainly, and they actually had interventions across four different domains based on risk factors within that given individual.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
So they had, uh, dietary, a dietary intervention, they had physical activity, they had, um, cognitive behavioral therapy for those who had, um, you know, some, potentially some mental health, um, concerns, and then they had, uh, online brain training. Uh, there was something similar done in the POINTER trial, uh, which was in older adults, now 60s and 70s, that was p- done here in the US. That was a replication of an older trial called the FINGER trial that was done in Finland. Uh, but what those guys did was something very similar. So it's a, a diet, exercise, um, monitoring and, and treating, uh, cardiovascular risk factors, and then brain training. So what the brain training looks like, um, so the POINTER trial is a good example. They did, um, they used a platform called BrainHQ, which is-
- AHDr. Andrew Huberman
BrainHQ?
- TWDr. Tommy Wood
BrainHQ.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
Um, which was, uh, developed based on the work of Mike Merzenich, um-
- AHDr. Andrew Huberman
Oh, yeah
- TWDr. Tommy Wood
Like one of the godfathers of learning and neuroplasticity, right? Um, and they do various tasks primarily focused on developing and maintaining processing speed. Um, some of that evidence goes all the way back to an older trial called ACTIVE that was done in the US in the '90s. It's still the biggest ever trial of like pure cognitive brain training, again, in older adults, so 60s and 70s. They had three different, um, training groups, the... uh, and then a control group. Uh, the training groups did m- memory training and kind of like, you know, mnemonics, memory palaces, that kind of stuff to help them remember. There was reasoning training, which is kind of like loting-- looking for patterns in numbers and letters, and then there was processing speed training, where in this example it's visual processing speed. So things flash up on a screen in increasingly small, uh, increments, so could be hundreds of milliseconds. And as you get better at doing it, that time gets shorter, and you have to remember what you saw and where you saw it on a screen. They just published a secondary analysis of the ACTIVE trial that showed that, um, those who did processing speed training with, uh, booster sessions at one in three years had a significantly decreased risk of dementia 20 years later. Um, and they've done some other studies showing that that kind of training improves cholinergic signaling in the forebrain, um, which we know is susceptible to, um, the processes of dementia. So in particular, it's this training, uh, to be able to improve either visual or auditory processing speed, which is not something that... You know, as you get older, you tend to not do activities that require you to process information quickly. Like driving is probably the, the, the main one. But you can do it in sports and music and, and o- other scenarios. But if you're not doing those things, processing speed tends to drop off sometime around 60 years old.
- AHDr. Andrew Huberman
When you say, uh, well, I say processing, you say processing [laughs]
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
Uh, processing speed, um, are you talking about reaction time, improving reaction time, or pushing people to, um, stay at the edge of, of reaction time? And when I say stay at the edge, I should clarify for people, some task where i- if you go too fast, you make errors. If you go too slow, there's also a penalty.
- TWDr. Tommy Wood
In this scenario, and there, there are, you know, studies that look at these different functions over time. Probably the, the biggest one looked at, uh, data that came from the implicit association test people might have heard of, where you get, um, show these pictures of different things, and depending on how quickly you respond, it tells you something about like your implicit asso- um, your like, your implicit thought processes. Um, but they took some of the data from that. Um, this was published in one of the Nature journals a, a few years ago. And what they showed was that, um, you can separate out reaction time versus processing speed because reaction time is just, is a, is a very, um, just the basic of response to a visual stimulus, whereas processing requires you... is, is based on how quickly you can process and remember the information that you're seeing.
- AHDr. Andrew Huberman
Actually think. [laughs]
- TWDr. Tommy Wood
You actually think, yeah. So what they showed in this study was that reaction time kind of slowly decreases on average in a population of, it was about 1.2 million people, slowly decreases in sort of like from about our 30s and then, and then maybe decreases even more once we get past about 60.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
Processing speed on average tended to be more stable until about 60 years old and then tends to drop off. So in what you're doing in these, um, training modalities is you're being shown information w- for a very s- short period of time and then having to remember what it was you saw and where you saw it. Um, so it requires you to actually think and, you know, remember, process the information rather than just like responding to a stimulus.
- 21:56 – 26:56
Enhancing Neuroplasticity with Age, Tool: Motor & Cognitive Challenge
- AHDr. Andrew Huberman
So for people that want to jump to the, okay, what do I do?
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Um, can we conclude, okay, if you like crossword puzzles, keep doing them, but do really hard ones for you. If you like lifting weights, continue to challenge yourself with those. If you like to run, you know, push harder. Or should it be we shift domains? You like to lift and run, great. Start swimming again, Andrew. I'm telling myself. [laughs] I used to... I, you know, I just notice over time, it's, it's such a cliché of aging, right? Um, that you... one does tend to become more narrow-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... quote, unquote, "set in their ways." You like what you like, you don't want, but like we know, you get busier. You probably don't actually get busier, but you convince yourself, "Well, I'll do-- I'm doing these things and I do plenty of them, so but I'm not doing these other things." Or for those of us, and I think this is everybody if they really ask themselves, uh, and answer honestly, you'd love to hold onto your motor function and cognitive function-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... as long as you can, maybe even improve it. Should we push ourselves to do something that's really far outside the box or maybe sort of current skill adjacent? So I think of those three categories. Uh, what, what do the data say? Uh, if you want the greatest effect for the minimum amount of time, assuming you're still gonna do all the stuff you normally do-
- TWDr. Tommy Wood
Yeah, yeah
- AHDr. Andrew Huberman
... but you're gonna add something else, should it be something really different, slightly different, or just push harder in the thing you do?
- TWDr. Tommy Wood
I think it's gonna depend a little bit on what it, what it is the things that you currently do, right? So like crosswords are a good, a good example. Even if you're doing hard ones, if you look at the work of people like, uh, Gloria Mark, the things like a crossword and Sudoku, th- they're less of like a true cognitive challenge, right? It's, it's almost has more of like a meditation, meditative like effect, right? Which can be a good thing, right? So you're focused but not challenged really. Uh, whereas if we're trying to build capacity, you need to spend some time doing something where you are both focused and challenged, um, cognitively. So that can come from, um, learning new skills, be they motor, language, social, um, and ideally as broad as possible because you're going to get Better, like overall stimulus as well as kind of like broader potential for, for transfer into other areas of, of daily life. In reality, the narrowness of the response or the breadth of the response is proportional to the narrowness or the breadth of the stimulus, right? So you could get really good at one very specific thing, or you could try and learn a new skill that requires a, that, that involves a wide variety of tasks. So I'll give, uh, like a, like an example is learning a new ball sport, right? That is gonna require multiple assets of motor skills, social skills. Um, it's gonna include both visual and auditory processing that's going to get faster and faster and harder and harder the better you get. So something like that, uh, creates a br- much broader stimulus, um, than, you know, if you get very good at one very specific brain training task on like one computer program, right? This is one of the main arguments against online or, you know, digital brain training, is that you get very good at doing that one specific thing, but it doesn't transfer over to other areas of your life. Whereas some of these broader, more complex, ultimately more human skills probably give us much broader transfer as well as, you know, you know, because of the, the, the multiple pathways or networks that are being activated.
- AHDr. Andrew Huberman
If my interpretation of what you said is correct, pick something hard.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Ideally, pick something that's a bit outside or really outside your current skill set, uh, that involves motor and cognitive aspects, like maybe, um... And, and that's kind of tricky to, to find, right? I mean, the, with sports stuff it feels motor and cognitive-
- TWDr. Tommy Wood
Hmm
- AHDr. Andrew Huberman
... 'cause you have to learn the rules of the game, you have to, in some cases interact with others. With cognitive stuff, um, the motor skills involved in writing or turning a page, they're, they're not that significant.
- TWDr. Tommy Wood
Hmm.
- AHDr. Andrew Huberman
Right? Um, even with a video game, I know video games can improve reaction time and visual search and things like that, but basically your thumbs get real, real good.
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
I actually went to a video game competition. They have teams. Uh, a kid that used to work for me, I was like, "What do you want for, uh, uh, kind of end of year gift?" And he's like, "I really want to go to this video game championship." And the kids actually who compete warm up their hands. The kids in the audience like have these styrofoam things that they clap so they-
- TWDr. Tommy Wood
Hmm
- AHDr. Andrew Huberman
... don't make noise, so they... And it was, it was a whole thing.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
So I don't want to take anything away from the, the real sport I, I discovered that is playing video games. But mostly what was moving was thumbs and fingers. Not a lot of large scale motor activity.
- TWDr. Tommy Wood
Yeah.
- 26:56 – 36:50
Learning New Skills, Dance, Sports, Arts; Psychological Benefits of Challenge
- AHDr. Andrew Huberman
So if you had to maybe throw out three or four things that are particularly potent plasticity inducers, what would those be?
- TWDr. Tommy Wood
This definitely doesn't have to be super complicated. So like the things that you mentioned earlier, so you, 'cause you mentioned exercise and then skills, right? And so you could do those things separately, right? I would... Maybe we'll get into why aerobic and strength training do different things to different parts of the brain, right? So ideally you do a little bit of both. If you don't feel super compelled to go and start a new sport, but you're getting these inputs from elsewhere, um, and so you, you would rather say learn a new language, right? Which we have some, which we have some good evidence for, then that combination is great. But if you're thinking about some of the things that we have very good evidence for that kind of hit multiple, um, networks at the same time, dancing is probably number one. Lots of-
- AHDr. Andrew Huberman
Learning a new dance?
- TWDr. Tommy Wood
Learning a new dance.
- AHDr. Andrew Huberman
Solo or with someone else? I'm sort of half joking, but some people dance on their own, some people dance with someone else.
- TWDr. Tommy Wood
So like dancing on your own in your living room, highly encouraged, right? It's a great form of physical activity. It's fun. You know, of course, the, um, the best evidence is for ballroom and line dancing, which generally requires... And so there are meta-analyses of these interventions in older adults showing that ballroom and line dancing have the greatest effect on cognitive function. And so both of those require other people.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
As well as learning, you know, various sets of, of movements. So you have, uh, you have skill learning, you have social interaction, and you have the physical activity component. There's probably also the musical component, right? You have to listen for the timing of the music and those kinds of things that, that is its own skill set. So dancing has a, a, a large body of evidence behind it. But then I think, you know, in the exercise realm, you've got all the sort of ball sports, board sports, team sports. Um, I think skateboarding would be a great example as long as you wear a helmet and don't hit your head, uh, too often. Ma- you know, most martial arts, again, as long as somebody's not punching you in the face too much. Um-
- AHDr. Andrew Huberman
Something like Brazilian jujitsu.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Yeah.
- TWDr. Tommy Wood
Exactly. So like you're, um, there's a, a physical component, there's a complex motor skill component. Usually there's a social component. There's a, you know, there's a lot of, uh, responding, reacting to the environment or your opponent, uh, right? So w- then talking about processing speed again. But then beyond that, there's some really interesting data on some other creative arts that do seem to have some effect on, um, you know, network stability and function in the brain. Particularly the networks like the frontoparietal network that we know is really important for like focus and attention, and its function does tend to decrease with age. Um, so, uh, things like, like creative or, or visual arts, um, some maybe some similar effects of learning a language. Um, a- again, um, uh, similar effects from learning to play video games. Yes, of, of course there's no like big motor patterns involved, but you're having to do, um, you know, solve complex problems, you know, uh, react quickly to, to a changing environment, that, that kind of stuff. So that's, you know, eight or nine different things that, that somebody could try. And like e- just one of those I think is gonna be a new skill, a new stimulus, often happens in a social environment. Um, a number of different things happening at the same time.
- AHDr. Andrew Huberman
Any particular, uh, instruments?
- TWDr. Tommy Wood
I don't think anybody's looked at instruments, like the difference in different instruments.
- AHDr. Andrew Huberman
Mm.
- TWDr. Tommy Wood
So I would say no. Pick, pick one that you would, that you feel motivated and interested to learn.
- AHDr. Andrew Huberman
Mm-hmm. Yeah, dancing by oneself has a lower shame quotient.
- TWDr. Tommy Wood
Well, the shame quotient I think might be, might be important, right?
- AHDr. Andrew Huberman
Oh. Uh-huh.
- TWDr. Tommy Wood
There's the, um, you know, there's the scum- the, the discomfort of making mistakes, and we know how critical that is for learning. And so, like your, uh... I think some of that c- can be important, too. But if you do it in a, in a class, everybody else is a beginner, you're all doing it together, maybe that adds a fun component because you can laugh at each other when you don't get it right, you know? So a, a, a few, uh, years ago I wrote a paper with my colleague J- uh, Josh Turknett about this idea that, um, potentially one of the reasons why we lose cognitive function as we get older is 'cause we stop giving our brain novel inputs or complex inputs that help maintain function, drive neuroplasticity, and I think one of the reasons that that happens is because adults hate being bad at things, right? You just, like this thought, right, you, you, you just imagined it, right? I'm in a dance class and I'm gonna suck at dancing, right? I, I imagine that I'm gonna take my wife to, to a tango class. It's something I've always wanted to do. But when I go in the first time, I imagine I'm gonna be like Arnold Schwarzenegger and Jamie Lee Curtis in True Lies. Have you... Do you ever see that movie? But anyway, so right at the beginning they're like, they're spies and they're doing the tango at this, you know, like gangster's mansion or something, and it's like he leans her over, she grabs the rose from the table in her, in her mouth. Like, I'm gonna try that and I'm gonna drop my wife, and she's gonna hit her head, she's gonna be mad at me, and lots of people are gonna see, and I'm gonna feel stupid, right? And so that's why we don't do those things. But it's so critical to driving those processes of learning, of neuroplasticity that we make those mistakes, that we have to kind of let go [laughs] of some of that, that we feel as adults, like we, we think that everybody expects us to be good at everything and the best at everything and, you know, we shouldn't fail, we shouldn't make mistakes. But as you have covered many times, um, it's so critical to, to do that. And so I think acknowledging that shame component exists and leaning into it is gonna be a really important part of trying to maintain this function over time.
- AHDr. Andrew Huberman
Couple of quick anecdotes-
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
... and then some encouragement to do the tango class. Um, I'll start with tango. My grandparents on my Argentine side did tango until their, into their 80s.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
So it can be done, but they learned it rather young.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Um, and Tim Ferriss, as I recall-
- TWDr. Tommy Wood
Yeah
- AHDr. Andrew Huberman
... ta- talked about this in one of his books.
- TWDr. Tommy Wood
He's a competitive tango dancer.
- 36:50 – 46:59
Flow, Clutch States; Virtuosity
- AHDr. Andrew Huberman
Maybe we could talk about flow for a second.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
You know, one of the most bastardized-
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
... terms in, uh, neuroscience performance, psychology, and the rest. When Csikszentmihalyi talked about it initially, um, when he really defined the term, it was about, um, being engaged in a process where you have a certain level of skill-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... but the thing you're trying to do is just beyond your skill level. So really striving a bit and that kind of general sense of well-being that can come from that. Nowadays, I think people assume flow is when you are able to do something in the absence of kind of feeling of effort. It's like you-
- TWDr. Tommy Wood
Yeah
- AHDr. Andrew Huberman
... just, you, you get the magic power kind of thing, which is not what flow was originally intended to, to mean. I'd like to know how you think of this concept of flow and whether or not it's even a meaningful term, and I, I, you know, tip my hat to Steven Kotler and others-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... who have, uh, w- written about it and, and studied it, and great respect for Steven and, um, what he's done, uh, with the concept. And, and, uh, and I think it's a meaningful concept, but I don't think we really know how to define it.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
And I think this is important in the context of plasticity because I think what we see in Harry Potter movies, and sci-fi and, um, you know, Fight Club and everything else is that suddenly we're just gonna be endowed with these powers just because we want them and need them.
- TWDr. Tommy Wood
Uh-huh.
- AHDr. Andrew Huberman
And that is not how it works.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
So is flow an expression of skill or is it the striving to attain a skill?
- TWDr. Tommy Wood
Mm. I think of flow as the maximal expression of a complex learned skill. Like you said, you're like right at the edge of your capabilities, but you're still managing to maintain, um, maintain function, whatever, whatever skill it is you're, you're performing at. The thing that really frustrates me is that because of that or, you know, some version of their definition of flow, people are like, "Well, I've always got to search for flow," like everything happens in flow and like we need to be in flow all the time, which doesn't make any sense to me whatsoever. [laughs] There's two different parts to this. So one is that people assume that for optimal performance you need to be in flow. That is not true. Um, flow is one version of your, of your, of, of being able to, you know, perform at the best of your abilities. If we think about this in terms of sports performance, there might be broadly two states associated with top level performance. One is flow states. The other is clutch states. And so a clutch state, um, you are still at the optimal level of arousal, right? If we think about the arousal c- curve and performance, which we can come back to. But so at the optimal level of arousal, which is required for you, you to perform the skill that you're trying to perform, but when you're in a clutch state, it still feels like hard work, right? So like there are ... You, you could talk to any athlete about a time that they, um, they performed well, they won, they d- you know, they did the, at the best of their abilities. But it was hard cognitive work, it was hard physical work. It was a slog, but they still managed to perform well. That's a, that's a clutch state. And people can perform at the best of their abilities in clutch states. Um, and you know, even though they're not in flow, it's not all coming to them easily, right? It requires them to like really focus and work hard to get, get the job done. And both of those are perfectly reasonable states in which to perform, and assuming that you have to be in flow to perform just isn't true if you look at like how, you know, athletes perform in the moment. The other side of it is that some people have intimated that flow is required for learning or like optimal learning happens in flow, which doesn't make any sense, right? If we, if we talked about making mistakes and errors and friction required for learning, that is not conducive [laughs] to flow because it's, uh, it can be stressful, it can be frustrating. And sort of the other side of that is if, you know, flow is expressing your skill, if you want to get better at that skill, you have to work even further beyond your current capacities, which are, which it will move you out of flow, right? Because of like the friction and the mistakes and the errors that come from that. So I think, yeah, flow is super interesting and I w- I wouldn't pretend to be an expert in flow, but there are all these other states where learning happens, where performance happens that aren't flow, and that's fine too, right? But sometimes it's hard, and that's okay. [laughs]
- AHDr. Andrew Huberman
I'm so glad you're here. Uh, I've been looking for this conversation for ... well, since I started the podcast because I completely agree about flow and the misunderstanding of the concept-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... of, of flow. I'd never heard of a clutch state.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
Um, is that a term that you coined or someone else coined?
- TWDr. Tommy Wood
No, no. It's, uh, in the sports psychology literature they'll talk about clutch states.
- AHDr. Andrew Huberman
So that's why I haven't seen it.
- TWDr. Tommy Wood
Yeah. [laughs]
- AHDr. Andrew Huberman
Yeah. 'Cause I'm very familiar with the neuroplasticity literature.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
But I've n- I've never heard of it. Maybe I'm just not up, up, up, up to date on my reading, but, um, thank you for introducing clutch state, which is when one is performing well but it's, it's involving, and this is a term I did make up, a sort of some limbic friction.
- TWDr. Tommy Wood
Mm.
- 46:59 – 50:55
Power of Practice
- AHDr. Andrew Huberman
Twyla Tharp, who's in her 80s, uh, world-class choreographer, sat in the chair that I'm in and described the daily routine of her world-class dancers. They go through the most basic drills-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... every single day, but every iteration for hours upon hours upon hours before they begin, quote-unquote, practice.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
Right? Before, before they try and embrace the, the new performance piece.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
But over and over and over, often after multiple hours of morning exercise. I think we, we don't see all of that foundational work and that it needs to be maintained, which raises a question: Do we always need to maintain, uh, practice the fundamentals?
- TWDr. Tommy Wood
Hmm. Before I answer your question, I, I think there's, there's a- another useful thing just kind of to remember that relates to all of this from, you know, in, um, you know, athletes and sports, particularly in, on the training side. There's this general idea of thirds, right? A third of your sessions-
- AHDr. Andrew Huberman
Mm-hmm
- TWDr. Tommy Wood
... training, um, learning, whatever it is, are gonna feel great. You're gonna feel really good. You're just gonna get stuff, you know, immediately. It's gonna just come to you. Um, a third will just be average, right? And a third are just gonna suck, and you just have to show up and get it done.
- AHDr. Andrew Huberman
But this is all in the same day? Or this-
- TWDr. Tommy Wood
No, no, just like-
- AHDr. Andrew Huberman
... across the week?
- TWDr. Tommy Wood
Across, across the week, across months, across years, right, this stuff undulates. And, uh, the, the, the main reason why I say that is because Related to this sort of glorification of flow is this idea that these things should just, like, always come easily to us. But that's completely antithetical to the idea that we have to work hard and challenge ourselves in order to build capacity, drive neuroplasticity. So there's kind of this weird tension between what people are seeking versus what is actually just the part of the, the grind of getting better and, you know, o- o- over time. And sometimes it is a grind and that's, you know, again, that's okay. It doesn't mean you're doing it wrong. You know, maybe it means you're doing it right. When you then think about maintaining the fundamentals, I think yes, but probably it's gonna depend on the scenario that, that, that you're th- that you're thinking about. Um, because sometimes the skill that you're performing, the fundamentals are kind of baked into that in, in some way. So it ki- kind of depends on what the, what the fundamentals really are. Maybe, you know, if it's, um... So I, I'm thinking about one specific study that was done in, in pianists. Um, so this is kind... It was kind of related to the Ericsson studies in, uh, in violinists, right? But this time they were, they were looking at, uh, uh, pianists. And so they had four, they had four groups, uh, older and younger. So the younger was like 20s and 30s, older were 50s and 60s, expert and amateur pianists. And so the experts came from, um, German, like, music conservatories. Um, and then they, they looked at, um, sort of basic skills related to, um, you know, moving the fingers and other things that, that you, you would do playing the piano. And, um, so they were to, like, very task-specific skills related to piano playing. And what they found was that the most important predictor of how well somebody performed at those piano-specific skills was not their age, it was how much they practice. So it's just that getting those reps in helps you maintain those sort of, like, basic functions. And maybe, right, when you're playing very complex piano pieces, you're encompassing all those fundamentals anyway, right? You don't need to, you don't need to, like, do your... You don't need to do your scales every day because some of that stuff is kind of built in. But you will also see people as they warm up, say, you know, maybe they will do scales and things 'cause that's part of just, like, you know, the, the warm up. Maybe part-- maybe that's routine, right? This is me getting in the m- in, in the mode of, you know, playing a complex piece. But then maybe some of it is just kind of helping to maintain those fundamental skills.
- 50:55 – 52:14
Sponsor: AG1
- AHDr. Andrew Huberman
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- 52:14 – 1:00:17
Tools for Focused Work & Learning; Distractions
- AHDr. Andrew Huberman
So now's your opportunity to kill the 10,000 hours myth. [laughs] I know other people have attempted to, but what, what does that really boil down to? Is it simply that about eight hours a day of practice for a dedicated period of time is what leads to rapid plasticity and that's what was measured? Or is there really a r- a, some sort of rule about time under a seeking clutch state?
- TWDr. Tommy Wood
The simple answer is what the study showed was that 10,000 hours was the average amount of time that an expert violinist had spent practicing by the time they reached 20 years old. That's what the study showed. They weren't even experts by that point. That was how much they'd practiced, you know, essentially in their youth. So that number of hours doesn't even translate over to true expertise in violinists in this one specific example. So I don't think there's some fixed number of hours, uh, required. It is interesting. Other parts of that study kind of looked at the, the, the practice routines of these expert violinists, and what they found was that they tended to practice for about two sessions of 60 to 90 minutes a day. And I think that's a pretty good rule, right? If you're gonna do something hard, you're pushing beyond your current skill level, focusing for 60 to 90 minutes, maybe with, you know, a couple of breaks in there, um, a couple of times a day. That's probably a- about as much as most people can do. And I think that also relates to how we perform on a day-to-day basis in other areas of life, right? We kind of expect that we can go to work and we can work really hard for eight hours straight during the day, but, like, the brain doesn't really work like that. If we're doing hard, um, cognitive work, right? You're being-- you're focused and highly challenged, as you might be if you're a, um, you know, a, a future virtuoso on the violin and you're trying to, you know, really practice and push yourself. You can only really do that for, you know, chunks of 20 to 30 minutes, maybe a couple of times with a break, right? So, like, that's why Pomodoro, even though there's no, like, good studies on the Pomodoro technique, like, those time periods, you know, 25 minutes with a five-minute break a few times, they do kind of fit into that kind of rhythm. That translates over to multiple areas where we might want to use our brains. Um, and just remember that Hard cognitive work and that process of learning can only really happen in those kinds of size of, of chunks if you wanna do them sustainably.
- AHDr. Andrew Huberman
Yeah. Before I started writing my book, somebody, uh, who's published several, uh, very well-received books said you can only write for about four solid hours per day-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... uh, broken up into a couple of sessions.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
I was like, [scoffs] "Come on."
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
I mean, like I'm, I'm not trying to boast, but I used to go into the lab and sit down and work on a grant for six hours or something like that. And I started thinking like, was it really six hours? Go in there, see my students in post-doc, sit down. Okay, then there's lunch.
- TWDr. Tommy Wood
Uh-huh.
- AHDr. Andrew Huberman
I need to walk my dog.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
You know, and there were some late nights, but then the next morning I'm kinda dragging because I was in, you know, in my office really late. And you, you get real honest with yourself real quick and you go, "Whoa, okay." In the periods of time where I definitely pushed to the six, eight, 10, 12 hours of just nonstop work as a deadline approached, there was a compensatory drop in-
- TWDr. Tommy Wood
Mm. [laughs] Yeah
- AHDr. Andrew Huberman
... output after, after you click Send.
- TWDr. Tommy Wood
Uh-huh.
- AHDr. Andrew Huberman
And so I, I think you're right. They're right. It's somewhere between maybe... I mean, you're saying 60 to 90 minutes and they're saying four hours, but not a whole lot more than that for real focused in clutch state work.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
So really digging in and no distractions, no phone, no checking your text messages, just, you know.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Do you ever give yourself, uh, forced constraints to get real work done?
- TWDr. Tommy Wood
Not to force it. I will say that, um, one of the best ways to like truly get deep focused work done is to eliminate distractions, right? That's one of the most important things that you can do. So close the email. I would like put my phone in a different room or something because like nowadays your own, you know, close Slack... Uh, I, I have Slack teams. My lab and I, uh, we, uh, interact on, you know, we message back and forth on WhatsApp. Like there's email. I've got like five or six different ways that people can like constantly try and get my attention, right? So like eliminating distractions is really important. And again, I, I return to Gloria Mark's work. She wrote an e- an excellent book called Attention Span, if anybody's like really interested in this. Um, but you get used to a pattern of distraction such that when you're, um, not actually being distracted, you will distract yourself, right?
- AHDr. Andrew Huberman
Wow.
- TWDr. Tommy Wood
Um, and-
- AHDr. Andrew Huberman
Wow
- TWDr. Tommy Wood
... but you can be trained out of that as well. But so you know that thing where you're trying to do work and you like reach for your phone for no reason? It's because your brain is kind of used to this pattern of th- you know, around about now I'm, somebody would text me or send me an email and I'll, and I'll reach my, for my phone. So you, you go looking for it-
- AHDr. Andrew Huberman
Mm-hmm
- TWDr. Tommy Wood
... even if it hasn't happened. But again, you can train yourself out of that if you, if you have periods where you're not getting constantly distracted. So I will eliminate notifications. Um, but at least for me, what I've found is that if I, if I have a ton of friction in terms of trying to get something done, I will usually step away from it, um, because there's something in there that just like needs to click or come back before I can like really engage in it or-
- AHDr. Andrew Huberman
Even if you're at a sticking point.
- TWDr. Tommy Wood
Yeah.
- 1:00:17 – 1:06:56
Nutrition for Brain Health, Dementia; Critical Nutrients
- AHDr. Andrew Huberman
In these studies, these large scale, uh, trials, uh, what was the diet intervention? Can we distill it down to some things that, um, everyone should do or ought to consider?
- TWDr. Tommy Wood
Most interventions in the sort of- Um, cognitive and psychological space are focused on some version of the Mediterranean diet. Um, there's, uh, the MIND diet, um, Mediterranean intervention to prevent neurodegenerative delay. It came out of the Rush, uh, memory and gen- and aging project. And it's basically just a version of the, um, Mediterranean diet kind of focused on, um, dementia prevention. And, and the way they initially created it was they looked at foods that people ate more or less of and created a score, and those who had a higher score tends to... You know, had a lower risk of later dem- dementia. It wasn't an intervention when it was, when it was first, um, developed. But that was kind of the version. It was a kind of combination of the Mediterranean die- diet and the DASH diet, which is, um, like a, a anti-hypertension blood pressure treatment type diet. So it's, uh, you know, seafood, vegetables, berries, whole grains, that kind of stuff.
- AHDr. Andrew Huberman
Not too much, uh, saturated fat or animal protein.
- TWDr. Tommy Wood
No. Yeah. And so this is very similar to the diet they used in the SMILES trial, which was the first randomized controlled trial in depression that showed significant improvements in, in mood symptoms. I think the, the principles are useful, but there's not necessarily a huge amount of evidence to say that, like, this is the way that you, you should or you have to eat, uh, to maintain cognitive health. There was actually, um, a big trial of the, of the MIND diet. It was published in the New England Journal of Medicine a couple of years ago, and they compared, uh, the MIND diet to standard caloric restriction. Um, and actually they saw similar benefits in both, in both groups.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
There have been big observational studies that have looked at how much their diet looks like a Mediterranean diet and those whose diets look more like Mediterranean diets, yes, they have a lower risk of dementia. Of course, right, this is observational data, right? So it's not... You can't say it's causal. But what's interesting in some of these studies, there's a big one that came out of the U- UK Biobank, was that they, um, took out individual, uh, foods or food components of the Mediterranean diet to see if that changed the relationship between the Mediterranean diet and dementia risk. And there was no food or, you know, olive oil or food group or, you know, eating more or less meat that changed the relationship between the Mediterranean diet and dementia risk. So what that tells me is it's much more about whole foods, they're nutrient dense rather than avoiding any, you know, you have to eat-- you have to consume lots of olive oil, right? Or you have to restrict meat. Because if those things are eaten in the context of all this other stuff, it's really that bigger context of diet quality and nutrient density that really matters. So the, the parts of diet that I think about are the, you know, the, there's three. So there's energy, there's nutrients, and then there's overall dietary pattern. So one of the confounding things about that trial I told you about with the MIND diet versus caloric restriction is you're like, "Well, the MIND diet should win out, right? How does caloric restriction do just as well?" And in the kind of average population, we tend to have some issues with metabolic health and have been in a state of chronic energy excess for some period of time. There's been some very nice studies that have looked at brain aging and brain volume or brain reserve, um, across different populations. There was, um, there was, uh, one group that looked at different, um, tribes in Bolivia, the Bolivian Tsimane who are a hunter-gatherer group, the Moseten who are kind of an intermediate group between sort of the Tsimane and like a standard kind of industrialized group, and then industrialized humans in the US and Europe. And what they found is this kind of this, um, bell-shaped curve between energy availability and brain volume. And in general, brain volume, right, the more the better, right, we think. And so if you're chronically calorically restricted, your brain is smaller, um, 'cause you just don't have the resources to invest in, you know, the structure, um, and to maintain it. At the other end, you see the same thing. So if you're chronically, uh, in a chronic state of caloric excess, you also tend to have a smaller brain on average, and this is related to metabolic disease, um, you know, and, you know, potentially what comes with it, um, higher levels of inflammation, high blood pressure, things like that that we know can negatively impact the brain. So the most important thing, and I think this is where some of the benefits of caloric restriction happened in that, in that trial compared to the MIND diet, was that, you know, people's cognition improved just because they decreased their energy intake to a point that was, you know, m- more, you know, w- was essentially kind of what their brain kind of needed or what, you know, kind of supported their overall physical health, which then affects, you know, cognitive health and, and brain volume and, and brain function. So the first thing to do is to make sure that you're eating enough but not too much, right? And that's very simplistic, but, like, energy is really critical. Energy availability, not too low, not too high. Then the next thing that you need is there are, is, is nutrients. We know there are several critical nutrients for, uh, related to cognitive function and risk of dementia. Um, the ones that we have the best evidence for are vitamin D, iron, omega-3 fatty acids, uh, the B vitamins, uh, involved, and the B vitamins involved in methylation, so particularly B12 and folate, also potentially B6 and riboflavin, although that might depend a little bit more on, on the individual. Then there are some other nutrients that, you know, have some pretty good evidence for them, so many of the on- antioxidant, uh, polyphenols, things that you get from berries, coffee, tea, chocolate, the carotenoids that make things orange, yellow, and red, um, lutein, zeaxanthin, astaxanthin if it comes from seafood. That's, that's what makes, uh, shrimp and salmon pink. Um, and then, you know, some other aspects like dietary fiber seems to have, you know, some, some benefits as well.
- AHDr. Andrew Huberman
Not magnesium?
- TWDr. Tommy Wood
So magnesium is absolutely, absolutely in there, in there too. Um, and in general, I think, um, and the... So magnesium, uh, zinc, um, then there's some of the structural lipid components, things like choline and ethanolamine that you might get from, um, nuts and seeds or eggs. They have some slightly less, you know, like less evidence. You know, really when you're looking at, um, brain changes over time and dementia risk, but they certainly do seem to be related to, to cognitive function. So there are some studies that show that those who have lower magnesium intakes tend, on average, to perform less well on some, some cognitive function tests. So all of those do seem to be important.
- 1:06:56 – 1:16:41
Nutrient Timing, Supplementation; Omega-3s, Tool: Blood Tests
- AHDr. Andrew Huberman
I have two questions about nutrients and brain health-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... in short and long term, and they have to do with interactions between nutrients-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... which, at least to my understanding, are rarely explored. You know, you'll see studies of supplementing omega-3 or having people eat some fatty fish or, or less and so on, but rarely in the presence or absence of some other vitamin that, you know, that can potentially impact the same pathways. So there's synergy. There's also, you know, necessity. So that could impact results. The other piece is on what timescale are these nutrients needed and on what timescale are they metabolized? So maybe to just kind of drill into the second question first. So, you know, I'm not out here as like the defender of supplements, but I've been taking supplements in various forms and eating whole foods and eating as... generally healthily, you know, less so when I was younger, but still pretty healthy and more so as I get older. But i- here's where my brain goes. Wait, whole food is great, but let's say dark leafy greens have a bunch of things in them that are fundamentally important for brain and bodily health. Great, and they have fiber, et cetera. How many times a week am I eating dark leafy greens? Let's say I do Monday, Tuesday, Wednesday, I'm great, but then I'm traveling on, you know, Thursday, Friday. Should I be just supplementing Thursday, Friday? Am I good until the next week? I think one of the reasons why eating really well, I think everyone kn- knows what that means, not... enough calories, not too many, mostly whole foods, et cetera, enough vegetables, fruits, and high quality protein and quality fats. I think the reason why supplements still become enticing to me, maybe even necessary, is because you can take them every day very easily.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
So you can make sure that you're i- in range and maybe above range. So let's take one of these things. Okay, omega-3 fatty acids. I, I believe that the data are pretty compelling. They can be helpful-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... for health, maybe even brain health. Certainly, uh, I believe that. But let's say the early part of my week is omega-3 rich and the later part of my week is omega-3 poor. Am I good? Versus, you know, spreading it out across the week. It just becomes difficult to eat in a truly healthy way i- if, uh, if it's the case that it has to be consistent every 24 hours. So what do we know?
- TWDr. Tommy Wood
So again, I think we're often tempted to overcomplicate this and try and think, "Oh, you know, I have to hit all these things at this interval, and if I can't do that, then I have to supplement." And in reality, we probably have more buffer in the system than, than we realize. So, um, omega-3 fats is a really good example. Your adipose tissue, your fat tissue, is a depot. You know, it, it kind of stores excess omega-3s. Actually, I wrote a paper o- on this with a colleague of mine, Rory Heath, a few years ago. The long-chain omega-3s that we have in our, in our fat stores, um, may help to explain why supplementation does or doesn't work in some of these trials.
- AHDr. Andrew Huberman
Mm.
- TWDr. Tommy Wood
Because some people just have more kind of hanging around. And if you eat more than you need on one day, um, especially in a state of caloric excess, um, that's gonna be stored in your fat tissue and then when, uh, you're sleeping or when you, uh, initiate, uh, lipolysis, the breakdown of fat, so particularly during periods like if you're doing exercise, those then get released and they... you know, the brain then has access to them. So there's some studies that, um, show that when you... Th- this relates to the form of the omega-3s as well. So many people will tell you that you have to take omega-3s in the phospholipid form, uh, which is like a, a special, y- it's a special supplement. Um, you can get it from krill, um, and the, the form is with the, the fat is attached to like a, a phospholipid head group, just like it would be if it was sitting in a, in a cell membrane. And there's a specific pathway for those to get into the brain.
- AHDr. Andrew Huberman
It's only krill or it's fi- fish oil also?
- TWDr. Tommy Wood
Uh, no. So fish tends to be the triglyceride form-
- AHDr. Andrew Huberman
Mm-hmm
- TWDr. Tommy Wood
... uh, which is your glycerol and then three fatty acids atta- attached. When you compare a single dose of phospholipid versus triglyceride form, then more of the phospholipid form gets into the brain. Some of this... You know, most of this comes from rodent studies. But what's interesting is that if you supplement over several days, it all kind of comes out in the wash because the triglyceride form-
- AHDr. Andrew Huberman
Mm-hmm
- TWDr. Tommy Wood
... um, cycles through the adipose tissue as a depot, and then it gets released and the brain can then use it. So if you're gonna take just one day of supplement and you want to get as much of that omega-3 in your brain, yes, you should take the pho- uh, we think you should, you should take the phospholipid form. But the form that comes in seafood, which is primarily the trigly- triglyceride form, is regulated through the body's fat stores. So this is a really long way of me telling you, if you eat some fish early in the week, you don't then have to supplement later in the week, as long as you've got kind of enough, and especially if you've consistently eaten seafood across your entire life because you probably have a bit of a depot. And so what you see in several trials where they've given omega-3s to decrease dementia risk or improve cognitive function, so many studies have, like that have been done. There was actually a very recent one that just came out of, of USC where they gave, uh, omega-3s for a long period of time. They measured omega-3 levels in the, in the CSF, right, in the spinal fluid of these people to show that this, the omega-3s were getting into the brain. They didn't see any changes in terms of cognitive function or, um, brain structure on an MRI scan, so then everybody's like, "Well, omega-3s don't work." But when you kind of squint at the data and, and they didn't ... quite give me the data that I wanted. But when you look at it, those, the people in the trial just didn't seem that omega-3 deficient in the first place. So right, if this isn't something that you need more of to start with, giving a load more of it isn't gonna make that much of a difference, right? And this is the case for all of these different supplements. So the best advice, if you have access to it, is to test your levels. Test your vitamin D levels. Test your hemoglobin and iron levels. Test your omega-3 levels. Test your homocysteine levels, which is, as a, as a marker of a B vitamin status, which we know is a, a risk factor for cognitive de- decline, dementia as well. So if, um, if you can test your levels and it shows that you need more, and yes, there are the, the normal ranges that you have on a blood test are not necessarily the same as the risk ranges. So, um, homocysteine is a good example. A normal range for homocysteine, which goes up if you need, uh, some of these methylation dependent B vitamins, the normal range might go up to like 15 or 16. But we know the risk is definitely elevated above 13 and is probably elevated above sort of 10 to 11. So what your target range really might be is, is probably lower than what the normal range might be. But we have very good evidence that if you then supplement when somebody is above that range and you bring that down, you see significant improvements in, in cognitive function or slowed cognitive decline. That is particularly the case for omega-3s and B vitamins that lower homocysteine. And so this is the interactions that you were talking about earlier, and this is the best one that we know of, although I'm sure there are many more. Like I said, there are lots of trials that have given omega-3s or have given, uh, B vitamins to lower homocysteine and just haven't seen much of an effect. And everybody goes, "Oh, well, they don't work." But there are now at least three randomized controlled trials that have shown that omega-3 status and B vitamin status interact, and they're dependent on one another. So if you give h- uh, B vitamins to somebody who has elevated homocysteine, you bring down their homocysteine, but they have poor omega-3 levels, you don't see any benefit, and that's been shown in two trials. It was originally shown in the VITACOG trial that was run out of the University of Oxford. Um, it was then, uh, replicated in the Bproof, uh, trial. Then the other side has also been shown. There was a, in the Omega AD trial, they showed that, uh, supplementing with omega-3s didn't result in any benefit if people had elevated homocysteine. So th- that's just one example, and you can imagine, like you kinda said, there are probably lots of these, and if we're not, you know, going into a study actually looking like, well, what nutrients does this person need and then supplementing with them, um, you, you, you're not gonna find any effect. You know, you shouldn't be surprised when there's a, when the, when the study doesn't show anything. Potentially the one recent, um, example of kind of just giving a broad-based kind of set of nutrients or with a multivitamin that seemed to work fairly well was the COSMOS study people may have heard of. It was thousands of people, of, of older adults, um, and they were given either a multivitamin or a, a flavonoid supplement.
- AHDr. Andrew Huberman
It's like a Centrum type vitamin.
- TWDr. Tommy Wood
Yeah. It was, it was Centrum Silver.
- AHDr. Andrew Huberman
Yeah.
- TWDr. Tommy Wood
Like the most basic multivitamin, just 100% of the recommended daily allowance. Not like, no mult- uh, no like massive doses of anything. And in that study, those who got the mil- got the multivitamins saw, you know, changes in cognitive function that suggested some like, some, some improvements and... But that was literally just covering the bases, right? No massive doses, the most basic multivitamins. So in the kind of general population, I think you could say that something like that is probably a reasonable strategy.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
But what they also showed was that, um, supplementing with this antioxidant cocoa flavanol was only beneficial in those who tended to have a poor quality diet to start with, right? So they just weren't getting many of these kind of compounds for their diet. If you're drinking a lot of coffee, eating a lot of berries, seeing a lot of fruits and vegetables, you probably don't need it 'cause you're already getting it.
- 1:16:41 – 1:18:19
Sponsor: Function
- AHDr. Andrew Huberman
I'd like to take a quick break and acknowledge our sponsor, Function. Function provides over 160 advanced lab tests to give you a clear snapshot of your bodily health. This snapshot gives you insights into your heart health, your hormone health, autoimmune function, nutrient levels, and much more. They've also recently added access to advanced MRI and CT scans. Function not only provides testing of over 160 biomarkers key to your physical and mental health, it also analyzes these results and provides recommendations for improving your health from top doctors. For example, in a recent test with Function, I learned that some of my blood lipids were slightly out of range. As a result, I decided to start supplementing with nattokinase, which can naturally help reduce LDL cholesterol, and it did. In a follow-up test, I could confirm that this strategy worked. My blood lipids are now back exactly where I want them. Comprehensive lab testing of the sort that Function offers is just so important for health. I mean, how else are you gonna know what's going on under the hood? And while I've been doing blood work for years, it used to be time-consuming, complicated, and expensive. In fact, I used to spend thousands of dollars per year trying to get this kind of data, and the data, frankly, were not all that good. But now with Function, it's extremely easy and affordable. A Function membership is only a dollar a day, $365 a year. And if you think about the information it provides and the health challenges it helps you avoid and the proactive things that it can do for you to enhance your health, I truly look at it as a savings. To learn more, visit functionhealth.com/huberman and use the code Huberman for a $50 credit towards your membership. Again, that's functionhealth.com/huberman.
- 1:18:19 – 1:23:10
Enhancing Brain Health, Nutrition & Supplements
- AHDr. Andrew Huberman
Thank you for that clarification. I, I look forward to a day, hopefully not long from now, where people get their blood work done. They are told and they decide, it's a collaboration after all, which supplements to take. Ideally, those supplements are tailored to them.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
So it's not gazillion tablets and capsules, and then, uh, they can redo their blood work and see whether or not things come into range.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
And of course, that should be measured against Subjective experience of wellbeing and sleep and all of that, that, that's not hard to do-
- TWDr. Tommy Wood
Mm-hmm
- AHDr. Andrew Huberman
... in today's environment of technology and trackers and blood testing. It's just that, uh, we're a little bit in the, um, still in the '90s, uh, even just the way that most people talk about supplements, certainly not you. But I think when people hear supplements and they go, "Oh, it's expensive urine. Okay, that's vitamin, minerals," maybe some of that is just getting, uh, urinated out. But then there's food replacement supplementation, and then there's supplements to get a specific desired effect-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... like speed up the transition time to sleep, get more slow-wave sleep, um, more focus, et cetera. So it, it's unfortunate that we don't have good nomenclature like we do in science-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... where, where, where words are very important so that people can communicate with accuracy.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
And I also wonder whether, okay, if, you know, one gram of, of, uh, omega-3, uh, EPA per day is good, um, but maybe three is better, even though I, I'm at, you know, upper range, upper reference range. And this is something that, like, nobody really wants to address because then it sounds like, quote, unquote, "biohacking." But ultimately, I think people wanna feel good. They wanna live longer. No one wants to do anything dangerous. I feel like we're really, like, in the, in, like, prehistoric times with, with how we think, how most people think about nutrition and supplementation. I feel like the last 40 years have been spent mostly focusing on what's bad for us. Okay, trans fat's bad. Fried food's bad. Eating too much, bad, right? Um, energy over, energy toxicity, bad. Um, too much alcohol, bad. Zero is better than any, but you could probably drink a little bit and be fine. Okay, if you're gonna take nicotine, don't smoke it or vapor, dip it. Like, we sort of figured it out.
- TWDr. Tommy Wood
Uh-huh.
- AHDr. Andrew Huberman
Right? Don't hit your head. If you do, don't hit it twice.
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
You know? Like, they, we've sort of been spending so much time on the don'ts that now I feel like we're in this exciting time of what can you do for one's health, and then there's this divide, right? Just eat whole foods. You'll be fine, and you've actually convinced me that we'll be fine. The question is could I be that much better?
- TWDr. Tommy Wood
This is really interesting to me because there's, there's, there's two different parts to it potentially, although I, you know, they may end up being the same thing. So one is if we're thinking about, if we're thinking broadly about improving brain health, cognition at the population level, what's really important is kind of raising the floor. Like-
- AHDr. Andrew Huberman
Mm-hmm
- TWDr. Tommy Wood
... what is gonna work for everybody and get most of us most of the way there? So, like, that really is improving food quality, um, and then, you know, access to those foods as well, right? Because that's diff- you know, that can be very inequitable. Like, can people afford it? Do they know how to cook it? Can, you know, can they access it? And then within that, I think we also know, we have very good evidence for cutoffs that predict risk, and if you can't get those, um, nutrients from food, I think we should supplement. I think, I, I like to call nutrients, like, the great leveler, of like, there's no point in arguing about different diets because your body requires these nutrients and, like, I don't care where you get them from, as long as you get them, right? So if you need to get them from supplements, I think that's fine. That, that, that should be fine. When you then get kind of to the next level, like how much further can we push function? My answer is I genuinely don't know. Like, when you say like-
- AHDr. Andrew Huberman
[laughs]
- TWDr. Tommy Wood
... you know, if I put... So if I, if I test my omega-3 and, you know, your omega-3 index, right? You said it was a, uh, the kind of the higher level. Maybe it's seven or eight or something like that. All right. If you push it to 12, is that better? I genuinely, [laughs] I genuinely don't know. Like, some of these more complex, um, AI systems, data collection, kind of seeing how you then respond individually. As, as long as you can perform your own sort of like personal experiments, right?
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
As much as you can, hold one variable constant, have some meaningful output that you can kind of track over time, see whether it works or not. Can we then aggregate those data to kind of better understand this? I'm excited to see where that goes. I will say that the best evidence we have just says, in reality, don't be deficient. If you can reach that threshold of not being deficient or insufficient, maybe that's enough. I'm hopeful that that's the case, right? Because then more people will get to that point more, more easily. But, you know, there's, there's a lot that we have to learn there.
- 1:23:10 – 1:32:56
GLP-1s, Peptides, Supplements & Evaluating Efficacy
- AHDr. Andrew Huberman
There was a time in the '90s and 2000s, um, where people would take stuff and do stuff. I'm not talking about anabolic steroids, although that was happening, too. Um, and the whole idea was find things that work, perform really well in one's job or in one's sport, assuming you're not breaking any rules, right?
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
But not tell anyone you were doing it.
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
And, and what changed, I think, were two things. One is there became a, a market value for telling people what one does in order to make money.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
So people started doing that, and I do believe sharing is good, right? But also there's this problem that goes with that, is that, uh, people who sit on the outside of kind of brain and, and sports performance or just life, just trying to maintain memory and do well in school and be, be, be a busy person and still get sleep and all of that feel like, oh, you know, it's, it, we're being sold this one thing that's supposed to make all the difference.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
And I think the thing that really came to, came in and changed all of it are the GLPs.
- TWDr. Tommy Wood
Hmm.
- AHDr. Andrew Huberman
I've never taken a GLP, but I'm just struck by like Americans are now willing to inject themselves. So now it opens up this whole thing about peptides, which, you know, the major consumers of peptides are not the bro science guys, like the gym bros. It's women-
- TWDr. Tommy Wood
Hmm
- AHDr. Andrew Huberman
... who... Look, I have female family members, right? Um, who have... And they'll tell me, and, and there's a long history of people doing and taking things and doing things for their cosmetic appearance and not necessarily sharing it with the world. So these are the performance-enhancing [laughs] um, substances of a, of a whole different kind, right?
- TWDr. Tommy Wood
Hmm.
- AHDr. Andrew Huberman
And so how is it that this peptide industry is so intriguing to so many people that, yeah, like jabbing yourself with something that is not FDA-approved? Like, people are doing it like crazy, even people who are ... kind of cautious about what they'll do and put into their body.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
Because of this bridge that the GLPs have made, it's so much easier now to just... Pe- people aren't as needle phobic. So I think we're entering a time now where people are saying, "Okay, you know what? The government, uh, the, the, the food pyramid, the whatever, the foo- food quadrants, like, yeah, that's just like if you don't wanna die, but I wanna feel great." And there's actually this potential that you and others are sort of offering. Like, you can learn things into your older age. You can be, uh, lean and have great posture into your 60s, 70s, 80s, 90s. We see examples of this. So I think that there's this pull f- we're getting kind of pulled forward towards-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... this promise, and I don't think that promise is all about avoiding the, the bad stuff. And people say, "Oh yeah, well, my grandfather lived to be 102, and he was smoking every..." Great. Like, awesome. But a lot of people don't have those kinds of genetics in their family.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
They really... And genetics play a big role. So I'm j- kind of editorializing here. I'd love your thoughts on how you sort of sit back and you look at the landscape of things. Um, eat right, exercise, get good sleep, socialize is awesome. But that is, just that is difficult-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... for people. That puts people into a clutch state. Just trying to do that while managing family and profession and cost of life, it, it, you know, cost of living.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
That's a lot. So I think people do want something that gives them more energy, gives them better sleep, you know, picks up their mood, you know. And I don't think there's anything wrong with thinking about those things as long as it feeds back to, to better behaviors.
- TWDr. Tommy Wood
Particularly when I think about this kind of, this new part of the, of the supplement ind- industry. And, and like you said, the, the, you know, peptides are just the next, they're the next iteration of the pills and potions and things that people have been-
- AHDr. Andrew Huberman
They're home to supplements more-
- TWDr. Tommy Wood
Yeah
- AHDr. Andrew Huberman
... than drugs because like they, they, there's no putting the genie back in the bottle. I don't care what the FDA does, and they can mark my words, people are gonna find their way to get their peptides because they love them.
- TWDr. Tommy Wood
Mm-hmm.
- 1:32:56 – 1:37:18
Stimulants: Feeling vs Performance
- AHDr. Andrew Huberman
what I, I want to get back to exercise-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... as, as a tool for opening the window for plasticity.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
Could it be that it's simply a matter of moving your body to get enough adrenaline in your body, norepinephrine in the brain, and maybe some dopamine as well so that the stage is set for plasticity, and it doesn't matter whether you jump rope, do jumping jacks, sprint, or do deadlifts? It's all about getting your brain into an altered, admittedly endogenous [laughs] chemical altered state of just more arousal, and then boom, you can go learn. Is it... I mean, could it just be that?
- TWDr. Tommy Wood
Before we get into the exercise, there's a, an interesting part with the supplements that increase arousal, right? So the stimulants in particular. And I am a big proponent of thinking about or, um, tracking how somebody feels, right? I think that how you feel is this kind of ultimate integration of all these inputs and outputs that the brain is kind of bring, bringing together, right? And we know that how you feel, so how an athlete feels, is a much better predictor of their performance than their HRV or any of their blood tests or any of that stuff.
- AHDr. Andrew Huberman
What are you asking them? Like, do you... How good do you feel today?
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Like, on one to 10.
- TWDr. Tommy Wood
Some, some version of that. I-
- AHDr. Andrew Huberman
10, I feel like I can conquer the world. One, I feel like..
- TWDr. Tommy Wood
Exactly. On... You know, and, and y- you, you can boil it down or, I mean, you can, um, spread it out to many more questions. So there's so- there's a question I call the rest Q which is all about, like, how you recovered, how recovered you feel, how motivated you feel to train or perform, that kind of stuff. But essentially it boils down to how feel, how good do you feel. If you feel good, you're more likely to perform well, and that works better than the vast majority of data that you, like biological, physiological data you can collect. There are papers that come out on this every year that essentially show the same thing.
- AHDr. Andrew Huberman
That's kind of cool.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Because mindset, as my colleague Allie Crumb has focused on so much, like mindset can be... You can be honest with yourself and you can lie to yourself and tell yourself, like, okay, you got a lousy sleep score, but, like, I feel good.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Or I'm... You know, maybe sleep scores are like they mean something, but today, pff. You know? [laughs] Right?
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
I mean, it... And it can work, right? I mean, in terms of performance.
- TWDr. Tommy Wood
Yeah. And so a- absolutely right. Then the, that gets into, like, the nocebo effect of, of how we think about either our sleep data or these other things, right? That, that can negatively impact our performance, and we have good, good studies, um, that, that show that as well. So, so I, I think that, like, tracking how you feel is really important. But when it comes to stimulants in particular, they s- they seem to dissociate how we feel versus how we perform, right? So there are, there are studies that show that, um, uh, giving people caffeine makes them feel like they're performing better, but they're actually performing worse on certain cognitive tasks. So there's been studies done with, like, the, the N-back task. So, like, very complex, uh, you know, working memory task, particularly as you get, like, to, like, N3 and you're, like, trying to remember did I see this letter three letters ago, right? In those kinds of complex cognitive tasks, people who take caffeine feel like they're performing better, but they're actually performing worse. They're making more errors or they're kind of, um, you know, they're reacting too quickly. They're not really thinking about it.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
And there is the similar data from other stimulants too. So there was a paper that came out in Science a couple of years ago w- uh, giving people, um, you know, methylphenidate, some of the, uh, some of the other, like, ADHD medications in people who don't have ADHD. These stimulant medications again show this dissociation between... So they feel great.
- AHDr. Andrew Huberman
You know, it's like the ca- the inverse of the cannabis thing where people think they've got all these great ideas and-
- TWDr. Tommy Wood
Feel like more creative
- AHDr. Andrew Huberman
... and then the next day even they are like, "Oh my goodness, this is dreadful."
- TWDr. Tommy Wood
Yeah. And that's again been f- like formalized in studies where you, where you can do these tests where then other people objectively see how creative were you. People taking cannabis felt like they were more creative, but actually they weren't. And so the reason why, um, I say this is that when we're talking about supplements and all these other things we're like, "Well, I feel much better, therefore it must be, must be doing something good." We know that with many of these supplements you can create this dissociation between how you f- how you feel and how you perform. Whereas some of these endogenous things don't have that effect. So that's why that kind of like endogenous increase in arousal using things like exercise is a much more reliable way to improve performance because you don't kind of get this dissociation between the two.
- 1:37:18 – 1:43:18
Exercise & Enhancing Cognitive Function, Tool: Optimize Exercise Volume
- TWDr. Tommy Wood
So with exercise in particular, we n- we, you know, know very well that Some period of exercise, it can be resistance training, aerobic exercise, very brief sprints, increase arousal, improve cognitive function across multiple domains, um, improve learning, um, and retrieval, right? So you, so you're definitely augmenting some of these processes of neuroplasticity. Some of that's gonna be related to the catecholamines and other things that get released as, you know, as you, as arousal increases. But we also know that different types of exercise have different effects on different parts of the brain. So yes, I think some of just, like, the general process of moving your body, um, and exerting effort definitely increases arousal, um, definitely improves cognitive function, improves learning, as long as it's not truly exhaustive exercise. Like anybody who's done some terrible CrossFit WOD or, you know, I used to be a rower. We used to do a 2K test on the rowing machine, right? You do a 2K test on a rowing machine, your brain does not work afterwards. It's like a six-minute flat-out, like, VO2 max kind of level of exertion.
- AHDr. Andrew Huberman
Yeah. Thanks.
- TWDr. Tommy Wood
Right?
- AHDr. Andrew Huberman
I'm gonna interrupt briefly.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Thank you for pointing that out because I think that people assume they have an infinite amount of energy, and there's crossover, and, um, I certainly have done, you know, extra sets to failure-
- TWDr. Tommy Wood
Mm-hmm
- AHDr. Andrew Huberman
... in a great morning workout, and then the, in the afternoon I'm dragging.
- TWDr. Tommy Wood
Uh-huh.
- AHDr. Andrew Huberman
If I hold back just a little bit in terms of volume-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... I find I get a real boost out of training.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
But I do low, low volume, high intensity.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
You know, usually two sets per exercise to, you know, two or three-
- TWDr. Tommy Wood
Mm-hmm
- AHDr. Andrew Huberman
... exercises per, per muscle. Like quadriceps being one muscle or something like that. If I do three, j- it's a small addition, right? The rest of the day I'm kind of dragging.
- TWDr. Tommy Wood
Yeah. Uh-huh.
- AHDr. Andrew Huberman
So leaving something in the tank-
- TWDr. Tommy Wood
Yeah
- AHDr. Andrew Huberman
... does seem worthwhile. Not during the sets, but leaving something in the tank in terms of volume really seems to help.
- TWDr. Tommy Wood
Especially if you want your, like, to perform hard cognitive work directly afterwards. Sometimes if you're trying to really push-
- AHDr. Andrew Huberman
Sure
- TWDr. Tommy Wood
... performance or adaptation, right? It's worth digging into that hole. But it really just depends on what you want to be able to do directly afterwards.
- AHDr. Andrew Huberman
I think student athletes, especially in D1 schools-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... they really, um, come to appreciate this. I've had a few of them in my courses over the years and, um, they really understand when they're pushing very, very, being pushed very hard in their sport and, um, they know that they have to sit in the front of the classroom, sit upright, do ex- take extra measures to make sure they're not dozing off-
- TWDr. Tommy Wood
Yeah
- AHDr. Andrew Huberman
... attention drifting, especially in the age of phones and iPads and, and things like that. It's very, very difficult. Um, yeah, thank you for, for mentioning that because they're just an extreme case of the rest of us. You know, we're told and we're all very busy, like, "Oh, you need to exercise, it'll help your brain" and be like, "Why exercise? I'm exhausted."
- 1:43:18 – 1:47:17
Long-Term Cognitive Health & Exercise, HIIT
- TWDr. Tommy Wood
If you're then thinking about the type of exercise that changes cognitive function or brain structure long term- Effort, uh, and intensity do seem to matter a lot more. But those studies have looked less at, well, how, how did that-- how do they feel directly afterwards, right? Now you're thinking about what's the kind of stimulus that drives change over time, and then intensity matters a lot as well. So, um, the, the best example, um, is with aerobic exercise on the kind of, uh, zone two up to kind of zone four, five sprint spectrum. So most people who listen to your show are, are probably familiar with a study where, uh, in older adults, they had them do, uh, brisk walking three times a week, forty minutes. Um, and when you kind of read the study and, and the heart rate, uh, levels they were trying to attain, it was basically zone two work. Forty minutes brisk walking three times a week for a year. And they saw significant increases in the volume of the hippocampus, uh, increases in, uh, VO2 max fitness, increases in circulating BDNF levels, though circulating BDNF doesn't actually get into the brain, but it's kind of telling you something about probably if BDNF is being produced in the brain, um, and improvements in memory with all of that. However, there's a much more recent study that took, again, older adults and randomized them across three different groups. One was like a low intensity group. Another group basically did kind of zone two type work on a treadmill three times a week, very simi- similar to that previous study that I mentioned. And the third group did, um, a high intensity interval training intervention, which was the Norwegian four by four protocol. So four minutes, uh, eighty-five to ninety-five percent of maximum heart rate. They had a three-minute rest in their protocol. They did that four times over. That's really hard.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
Anybody who's done the Norwegian four by four, if you then say, "Well, hey, do that three times a week for six months," like that's-
- AHDr. Andrew Huberman
That's three times a week
- TWDr. Tommy Wood
... three times a week for six months. That's, that's pretty intense. But what they showed was that that high intensity interval training group, they improved their fitness just as well as the zone two group, interestingly. But they had much better improvements in hippocampal function and maintenance of hippocampal structure on an MRI scan. And they maintained that benefit for five years after the six-month intervention. So they worked really hard, um, for six months, but that, that benefit was maintained for, for a really long period of time. And in several analyses within that study, they basically show that the harder people worked, um, and the more cortisol they released, the better the benefit. And so this is important because nowadays there's... or, you know, there's several people out there saying, "Well, don't do high intensity exercise. It releases cortisol. That's stressful. Your body can't handle it," right? This study directly shows that working really hard, releasing a lot of cortisol in high intensity interval training actually improves hippocampal structure and function, um, over, over time. So yes, I imagine after they did their workouts, their brain wasn't maybe working at its best, 'cause that's a hard workout. But over time, this was this really strong stimulus that then resulted in significant improvements.
- AHDr. Andrew Huberman
Forgive me if you said it and I missed it. Uh, what was the form of exercise? Was it rowing or biking or running?
- TWDr. Tommy Wood
It was on a treadmill.
- AHDr. Andrew Huberman
Treadmill.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Uh, really interesting. Um, and you said at about eighty-five percent of max heart rate?
- TWDr. Tommy Wood
Yeah. So that's, that's a typical Norwegian four by four protocol. But I, I don't think that's the protocol you have to do. I, I think it's just this process of high intensity exercise that it releases a whole bunch of myokines and lactate in particular. We know that lactate very easily gets into the brain, generate, you know, stimulates BDNF production as, as kind of part of that support of neuroplasticity or augmenting recent neuroplastic processes. I think there's something about that, just that high intensity work that drives some of those factors that then support structure and function.
- 1:47:17 – 1:48:31
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- AHDr. Andrew Huberman
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- 1:48:31 – 1:54:24
Cortisol Benefits, Acute vs Chronic Stress
- AHDr. Andrew Huberman
Yeah, uh, two things. Super interesting, um, comparison between these studies. Um, and as somebody who incorporates one day a week of four by four type-
- TWDr. Tommy Wood
Uh-huh
- AHDr. Andrew Huberman
... exercise and one day of longer, slower cardio, maybe I should try maybe doing a bit more of the high intensity stuff.
- TWDr. Tommy Wood
Well, I think if you want it to be sustainable for long periods of time-
- AHDr. Andrew Huberman
Mm-hmm
- TWDr. Tommy Wood
... like, I would typically say one day of high intensity work is fine.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
Right? 'Cause you probably-- you wanna be doing some resistance training. You probably-
- AHDr. Andrew Huberman
I'm doing that three days a week.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
I do one long slow, for me, jog-
- TWDr. Tommy Wood
Yeah
- AHDr. Andrew Huberman
... of about sixty minutes, uh, forty-five to sixty minutes, and then one kind of in moderate-
- TWDr. Tommy Wood
Yeah
- AHDr. Andrew Huberman
... kind of maybe more like zone three, four.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
So thank you for putting in a, a strong, um, word for cortisol not always being the bad guy.
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
Um, people are so afraid of cortisol. You want your morning cortisol high. It's gonna make you sleep better at night. You'll have more energy during the day. It's, uh, it was interesting to me to dive into the literature on cortisol and find that a moderate int- a moderate intensity resistance training session or cardio session Probably a little bit easier than the, uh, four by four will triple one's baseline levels of cortisol and like... Or quadruple it. It's transient.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
But nobody's freaking out about these workouts.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
But they're afraid to get in a cold shower, which doesn't have nearly the same impact on cortisol or, um, it's kind of wild how afraid of cortisol people are. People think they're gonna get Cushing syndrome. It's been... I don't know what the psyop on cortisol was all about, but you know, you're gonna get moon face. You won't be able to lose, uh, abdominal fat.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
I mean, there is a, a real condition, which is, you and I know as, uh, Cushing syndrome, where cortisol is, is pathologically elevated, but come on, folks. Like, cortisol goes up, cortisol goes down. You have that but 20, 30 fold from the morning until night in a healthy individual. So what do you think it is that, that people get, you know, like, afraid of cortisol, afraid of, uh, some stress? I mean, like, your, your hippocampus obviously... In this case, their hippocampus got better.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
It's not dissolving into a puddle of its own tears. [laughs]
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
What, what is this? What did, what did y- our predecessors do wrong, you know?
- TWDr. Tommy Wood
So-
- 1:54:24 – 2:03:37
Resistance & Aerobic Exercise, Brain Gray & White Matter, Cognitive Health
- AHDr. Andrew Huberman
Resistance training.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
Um, is there a particular protocol for resistance training that opens the opportunity for plasticity better than others that is supported in the literature?
- TWDr. Tommy Wood
Again, two different windows, say, of, of action. So there's th- that, that acute kind of arousal and th- this would be, um, you know, you, you go in the gym, you do a couple of sets. You're not maxing out. Um, you know, it's, it's probably gonna be your fairly typical couple of sets of, uh, eight to 12 reps, kind of 80% of, of max, something like that. You do like-
- AHDr. Andrew Huberman
Compound movements?
- TWDr. Tommy Wood
Yeah. So most studies use machines, right?
- AHDr. Andrew Huberman
Yeah.
- TWDr. Tommy Wood
Um, so maybe do a, a leg press and a chest press and a lat pull down.
- AHDr. Andrew Huberman
Okay.
- TWDr. Tommy Wood
You know, shoulder press.
- AHDr. Andrew Huberman
But multi-joint movements.
- TWDr. Tommy Wood
Multi-joint-
- AHDr. Andrew Huberman
Yeah
- TWDr. Tommy Wood
... movements, usually with machines. And again, if that takes 20 to 30 minutes, that kind of shows some similar effects to that like 20 to 30 minute jog that I talked about in terms of some, some acute bumps in, in, in cognitive function, probably through, through arousal.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
The mild activation of those arousal pathways. Actually quite similarly, the, the... I mean, probably, um, slightly higher intensity will also be beneficial as long as you're able to Uh, recover over time. Like that, that, that recovery is, is critical, just like I was just saying in terms of any kind of adaptation. Um, there were several studies of resistance training looking at cognitive function and, uh, brain structure over time. I say several, it's like three or four. In older adults, and they typically do two or three times a week, five to six exercises, three sets of eight to 12 reps, very, yeah, very similar. Um, so those multi-joint machines in, in the gym that anybody can do and that they're in any gym.
- AHDr. Andrew Huberman
Presses, pull-ups, rowing, pull-downs.
- TWDr. Tommy Wood
Correct. Yeah.
- AHDr. Andrew Huberman
Leg press.
- TWDr. Tommy Wood
Leg, leg press.
- AHDr. Andrew Huberman
Hamstring curl.
- TWDr. Tommy Wood
Exactly.
- AHDr. Andrew Huberman
Okay.
- TWDr. Tommy Wood
Yeah. And what you tend to see is that if you do that for at least six months, so the, the study's gone for like six to 12 months, you see significant, um, changes in the structure of the white matter of the brain, and with that, improvements in executive function in particular.
- AHDr. Andrew Huberman
Do you want to remind people what white matter is?
- TWDr. Tommy Wood
Yes.
- AHDr. Andrew Huberman
Just for, for the n- for the newbies.
- TWDr. Tommy Wood
Very broadly, you have white matter and gray matter in your brain. In the human brain, white matter makes up approximately 60%, uh, more than, um, most other species, any other species. And so like the wrinkly outer part of your brain, the cortex, that's gray matter. You also have more gray matter deep inside the brain. In between that is the white matter, which is where you have, uh, the myelin sheaths on your axons. That's what allows those, uh, nerves to conduct information really quickly. Whereas aerobic exercise on that kind of intensity spectrum we just talked about seems to particularly benefit the gray matter, which includes the hippocampus. Resistance training seems to particularly benefit the white matter. Um, and so you see improvements in a white matter structure, which... And, and changes in white matter structure with age are one of the best predictors of cognitive decline with age, interestingly. Like outside of other things you see in terms of neuropathology, amyloid, tau, et cetera, that loss of white matter structure and function is, you know, closely tied to cognitive decline over time. So you see improvements in structure and function of the white matter, and, uh, potentially improvements in something that, uh, we call white matter lesions, which tend to happen, um, around areas of poor blood flow, uh, within the white matter of the brain. Um, and with that, improvements in executive function. So, um, uh, aerobic exercise is gray matter and memory, and resistance training is, um, white matter and more sort of executive type decision making, processing speed type functions. You know, we talked about, uh, lactate and some of these other things that might increase, uh, I- um, uh, BDNF with the aerobic training. In resistance training, the, I, I think the primary mediator of that, or one of them, is IGF-1, which is in particularly increased with resistance training. We know that IGF-1 is really critical to the development of white matter, uh, you know, right, you know, in the womb and then as a baby, and it seems to be part- also really important for, for white matter structure then throughout, um, the lifespan. So resistance training is a really great way to then create these boosts of, of IGF-1. So that's probably, that's, that's probably part of, of, of why we see that difference. But that, that's why you need to do both. Though they may have similar kind of acute effects in terms of cognitive function, they seem to be having very different effects in terms of the structure and function of the brain long term.
- AHDr. Andrew Huberman
I so appreciate that you're basically telling us that different forms of exercise impact different critical aspects of brain structure and function.
- TWDr. Tommy Wood
Mm.
- 2:03:37 – 2:09:47
Cognitive Decline, Dementia, Alzheimer’s Disease, Modifiable Risk Factors
- TWDr. Tommy Wood
You know, ideally we can, we can act much earlier in that trajectory, and that's increasingly being accepted in the neuroscience and neurology communities that actually we could potentially change that trajectory or at least decrease risk. And so within dementia, there are, as an umbrella term, which is essentially the loss of cognitive function such that you can't look after yourself on a day-to-day basis. You can't do the day ... you know, sort of the, the basic activities of daily living. Alzheimer's disease is the most common. It makes up about 60 to 80% of, uh, cases of dementia. Um, the next most common is vascular dementia, although vascular dementia and Alzheimer's disease overlap a ton. Like the vast majority of people who have Alzheimer's disease also have some element of pathology or changes in the blood vessels in their brain, which is what you get, uh, with vascular dementia. And then there's also dementia with Lewy bodies, um, uh, frontotemporal dementia, and then, uh, dementia related to Parkinson's potentially. Although that overlaps a lot with, um, Lewy body dementia. And, and dementia and Parkinson's may just be ... may actually mostly be Lewy body dementia. But we've gotten to a point now where it's generally accepted that potentially half of cases of dementia are preventable, and I think the majority of that falls into those first two buckets, Alzheimer's and, and vascular dementia. Although, uh, metabolic disease and other risk factors for Alzheimer's disease also increase the risk of Parkinson's disease and, and those other dementias as well. When you then think about Alzheimer's disease specifically, there's, there's one small slice of Alzheimer's which is like monogenic dominant mutations that you have in either ... uh, m- where most of them happen either in the presenilin genes, presenilin one and two, or the amyloid precursor protein gene. They make up, at this point, less than 5%, maybe as little as 1% of Alzheimer's disease. So we kind of ... we set those to the side a little bit. The vast majority of Alzheimer's disease is what we would call late onset Alzheimer's disease, although it's happening actually earlier and earlier in s- in some populations. Yes, there's a genetic component. Um, your APOE gene is your probably your most common, uh, risk gene. It's also associated ... There's also polygenic risks, so thousands of genes can give you a little bit more or a little bit less risk of, of, of Alzheimer's disease. But it's much more related to lifestyle and the environment than, say, that, that kind of early onset monogenic, uh, Alzheimer's disease. And the, the kind of the best accepted, um, review of all of this, um, is, is run by the Lancet Commension- Commission on Dementia Prevention, uh, overseen by Professor Jill Livingston, and their most ... the most recent version of this suggested that there were 14 risk factors who between them accounted for about 45% of, uh, dement- dementia risk or dementia cases, and that, that are modifiable. So early life education, high blood pressure, diabetes, hearing loss, vision loss, brain trauma, um, high, uh, high cholesterol they recently, recently added.
- AHDr. Andrew Huberman
High LDL.
- TWDr. Tommy Wood
High LDL cholesterol, low physical activity. So this is all related to the things we've already talked about, right?
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
Maintaining good physical health, maintaining, uh, maintaining inputs, getting inputs in the first place, right? Education is, is, uh, is critical. Um-
- AHDr. Andrew Huberman
And hearing loss, as I recall, was an im-
- TWDr. Tommy Wood
Yes
- AHDr. Andrew Huberman
... portant one.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Right? Uh, uh, in, in reference to h- to inputs.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Like you don't want sensory input degraded.
- TWDr. Tommy Wood
Absolutely. So hearing loss, vision loss, um, social isolation. Um, they didn't ... Uh, there was quite ... So two things they didn't include, um, that were fairly controversial and were sort of debated, letters were written to the editor and all that kind of stuff as happens in, in academia, uh, related to ... So they didn't include sleep loss or sleep deprivation as a risk factor for dementia even though the evidence, particularly if you're con-
- AHDr. Andrew Huberman
Didn't look at it or didn't include it?
- TWDr. Tommy Wood
They didn't include it. So like they talked about it, but they felt that the level of evidence wasn't high enough, though it was probably as high as some of the other things that they included.
- AHDr. Andrew Huberman
It's a tricky one. I, I don't want to take us on too much of a tangent, but having looked at these data a lot, I do think that people need to get enough sleep, but some people like myself do fine on six and a half or seven hours, and other people can do fine on only seven or eight or nine. Very few people are A-okay all the time on just four to five hours-
- TWDr. Tommy Wood
Yeah
- AHDr. Andrew Huberman
... for prolonged periods of time. But w- but when we say not A-okay, what tends to happen with shift work or people that are chronically sleep deprived is most of the other things you're talking about get worse. LDL goes up, stress levels goes up-
- TWDr. Tommy Wood
Diabetes, obesity
- AHDr. Andrew Huberman
... diabetes go- So it's It's like, uh, I can understand why they might not have included it, but it seems so foundational to me that it does seem kind of a shame
- TWDr. Tommy Wood
Part of it is related to how they analyze the data, so we can, we can, we can get to that. But I, I mean, in reality, when you look at the data on sleep loss and dementia risk, the cutoff is really around six hours. So if you're consistently sleeping fewer than six hours, that's where risk starts to increase. So that, that kind of fits.
- AHDr. Andrew Huberman
Sounds about right.
- TWDr. Tommy Wood
Yeah. Yeah.
- AHDr. Andrew Huberman
That sounds about right 'cause it, it's the... I think it's the la- it's the lack of those last two cycles where... that are REM enriched.
- TWDr. Tommy Wood
Mm-hmm. Yeah.
- AHDr. Andrew Huberman
You know, 'cause in the beginning of the night you get your growth hormone surge, you get a lot of deep sleep, assuming you're, you know, doing things right during the day, and, and then it's those last, you know, two 90-minute-ish cycles that you glean most of your REM.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
And if you're not getting those night in and night out, and night in, night out, like sooner or later you're gonna have issues.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Yeah.
- 2:09:47 – 2:18:28
Shingles Vaccine & Dementia Risk; Tool: Avoid Illness for Cognitive Health
- TWDr. Tommy Wood
to do.
- AHDr. Andrew Huberman
Can I ask you a question?
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
It's gonna be a very controversial one.
- TWDr. Tommy Wood
Mm-hmm.
- AHDr. Andrew Huberman
But, um, there are people arguing... There are very smart people, I should say, arguing that the shingles vaccine-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... is lowering rates of dementia significantly. I haven't looked at those data closely yet. I plan to. But it certainly is intriguing given the data that herpes viruses of various sorts have been correlated-
- TWDr. Tommy Wood
Mm-hmm
- AHDr. Andrew Huberman
... with, uh, Alzheimer's.
- TWDr. Tommy Wood
This comes off the back of three or four very large natural experiments that have been done in, in various countries. And really how you interpret these data is gonna depend a little bit on your kind of risk tolerance and, like, how, uh, what, what you think should be done in terms of the level, level of e- evidence required to, to intervene. So I'll describe the studies in a second, but some people are definitely, uh, saying, you know, if you want, if you want to say that, um, the shingles vaccine decreases dementia risk, you ha- have to have a clinical trial that's adequately powered to show that, and there is a trial like that being planned currently.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
So the, the studies that have happened so far, uh, there was one in the UK in, in Wales, uh, one in Australia, uh, and one in Canada, and in each of those countries what happened was that on a single date, a huge tranche of people became eligible to get the shingles vaccine, whereas if they were born one day earlier, they weren't eligible. So you get what you call, like, a natural experiment, where from one day to the next, those people shouldn't be that different otherwise. And, and they showed that, you know, rates of other diseases weren't that different, rates of, uh, uptake of other, you know, healthcare and other vaccines weren't, wasn't that different. But there... Different, but there was a, a big shift in the uptake of, of the shingles vaccine. And so what they con- essentially consistently showed across all those different populations was that those who got the shingles vaccine, um, or were eligible to have the shingles vaccine, depending on whether they had access to the data on whether people got it or not, had a, had decreased risk of dementia, and that was consistently seen across those three groups. All those three trials used an older version of the shingles vaccine called Zostafax- Zostavax, which was a live attenuated vaccine. There's now a newer version, uh, called Shingrix, which is a recombinant vaccine, and there was a study done in the US that, um, compared people who switched from... You know, there, there was a similar switch from Zostavax to Shingrix and, and saw that Shingrix, uh, was associated with a, with a lower risk of dementia compared to Zostavax, although both were associated with a lower risk than none. When you look at some of these trials, um, or studies, 'cause they're not trials, people have made the, a very fair comment, which is that when you look at the trajectory of dementia over time, you look at something called a Kaplan-Meier curve, so it's like a survival curve. So, like, um, every time somebody gets a case of dementia, like, the line goes up, and you look at the trajectory of the two lines, those who've got, you know, got the, uh, vaccine or not. They diverge very early, which kind of says that, oh, it only takes a couple of months to kind of see this difference in dementia risk, which you, which you wouldn't really expect based on, like, the natural course of dementia takes years to happen.
- AHDr. Andrew Huberman
Hmm.
- TWDr. Tommy Wood
So, um, this is very common in these kinds of studies. Um, and it, it's, it's, uh, due to residual confounding. So there's, like, something inherently different about the populations that may be driving some of this different, right? They were, they were gonna get less dementia anyway, and so maybe the shingles vaccine isn't having that big of an effect. But I would say that having looked at all those trials and all those data, I'm fairly... You know, I'm convinced enough that, um, there's a, there's a signal there. There should be a randomized control trial. That's, that's happening. But there is a number of reasons why this might be the case. One, uh, it obviously red- we know it reduces cases of shingles. Shingles can be very painful. It can, you know, can, uh, change how people interact with the world. You stay at home. You don't feel good. You're in a lot of pain for a long period of time. That can be, that can go for, you know, many months. It's rare for it to last many months, but it can, can last a long time. Um, then, you know, there's... They've hypothesized Uh, in some of those papers that the magnitude of the reduction of dementia risk didn't map perfectly onto the reduction in, uh, in sh- cases of shingles, right? There had to be something else going on as well. They've suggested that it may be, um, due to, like, an immunomodulatory effect. It may be because you're also suppressing other viruses like herpes simplex virus that we know, uh, may also be associated with, uh, certain cases of dementia or Alzheimer's. Um, and the reason... You know, one of the, uh, arguments for the immunomodulatory effect is because not in all the studies, but in most of the studies, there's a slightly bigger signal in women than there is in men. Um, and it may be that that sort of, um-
- AHDr. Andrew Huberman
Meaning it's more effective in women
- TWDr. Tommy Wood
... more effective in women than it was in men.
- AHDr. Andrew Huberman
And we should mention that the shingles virus lives on neurons.
- TWDr. Tommy Wood
Yes.
- AHDr. Andrew Huberman
Yeah. The herpes viruses tend to live on neurons. Uh, and they hang out on neurons, which is why people who, you know, uh, get herpes one infections will get a cold sore at a particular location that will come back because it's living on the trigeminal nerve-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... that's just, you know... Uh, I think people don't often understand that viruses can, you know, harbor in, in particular cell types.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
And, uh, so the logical link between herpes viruses and, and, uh, dementia risk is, you know, it's not... I mean, that, that alone is not a, a causal relationship-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... but it, but it makes sense mechanistically.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
And a fundamental feature of herpes viruses is they generally don't kill the neuron.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
They can, but that's why they stay alive. These viruses are very smart.
- 2:18:28 – 2:24:04
Concussion, Traumatic Brain Injury (TBI), Creatine
- AHDr. Andrew Huberman
I realize that we could and probably should do an entire podcast about traumatic brain, brain injury and concussion.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
But as a teaser for that-
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
Um, are there any things that people should do and/or take in the immediate aftermath of a head hit? Now, I'm not talking about, uh... Well, hopefully people are getting checked out for brain bleeds-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... and things like that. So I'm, I'm talking about moderate concussion. Someone got their, quote-unquote, "bell rung." Uh, they slipped and fell. Uh, they got clipped in soccer practice. Um, their kid's a little dizzy. Now, uh, of course, if somebody young or old is vomiting or, you know, not able to sleep or real issues, I mean, everyone should probably be checked out in the, in the first case. But I get asked this question all the time. Is there anything that people can take to kind of get over mild concussion-
- TWDr. Tommy Wood
Mm
- AHDr. Andrew Huberman
... or moderate concussion?
- TWDr. Tommy Wood
The evidence base on this is a little shaky, but I, I think for most things it, it kind of fits into this idea of positive asymmetry, right? Low risk, high potential for benefit. And there have been lots of... You know, there have been randomized control trials to kind of look at some of these things. So we, a couple years ago, we published a paper looking at different nutritional supplements after concussion that, you know, we have some reasonably good evidence for. So, um, yes, you should be seen by a doctor. You should get whatever scans and, you know, immediate medical care that you need. Absolutely, right? That's... We're assuming all of that is done or, or, or will be done.
- AHDr. Andrew Huberman
Yeah. Rule out bleeds.
- TWDr. Tommy Wood
Yeah. Immediately, there are a couple of things that I think we know, um From sort of, um, animal studies that translate fairly well onto, onto humans, but also some, you know, maybe some observational studies in humans. But, uh, a couple of things are important. So one is temper- temperature ma- management, temperature regulation. There have been ... This is what my PhD was actually in hypothermia after acute brain injury.
- AHDr. Andrew Huberman
Hyperthermia.
- TWDr. Tommy Wood
Hypothermia.
- AHDr. Andrew Huberman
Hypothermia.
- TWDr. Tommy Wood
Yeah, so cooling down.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
Although I did do some studies where we, you know, we heated up, and that makes things worse. So this kind of pertains to what I'm about-
- AHDr. Andrew Huberman
I can imagine
- TWDr. Tommy Wood
... what I'm about-
- AHDr. Andrew Huberman
Brain doesn't like to get too hot.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Yeah.
- TWDr. Tommy Wood
That's the b- essentially what I'm about to say. So there have been lots of studies where they've done cooling, hypothermia in people after traumatic brain injuries and concussions. Hasn't really shown much of an effect. What seems to be important is preventing hyperthermia.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
So, um, one of the effects of cooling somebody down is that they don't get hot. So that's probably something that's really important. So often concussions happen in a heat-stressed environment. You're on a football pitch. It's August in Alabama. It's 40 degrees, right? Get inside. Get cool as quickly as you can because there are, there are studies that ... And that doesn't mean you have to get in an ice bath. Just don't be really hot. If you get a fever, which you might, might do after a more significant injury, you know, Tylenol or something like that to help maintain thermo-regulation will, will be really important. The next is, uh, blood sugar regulation. So we know that after a significant brain injury you have increases in, in blood sugar. That's associated with worse outcomes. Some of it's like what's cause, what's consequence? Is the injury driving the blood sugar? Is the blood sugar driving the injury? I think an easy thing to just say is I would avoid any super sugary refined carbohydrates that might just sort of, you know, uh, kind of pile on, for want of a better word, right? So-
- AHDr. Andrew Huberman
What about alcohol?
- TWDr. Tommy Wood
So alcohol, um, I would avoid as well, mainly because it impairs sleep, and we know that sleep is gonna be critical to recovery. Some people would say s- something similar about caffeine acutely after injury because it's a, it's a stimulant. Um, one thing that ... Well, the reason why hyperthermia or getting too hot makes the injury worse is because it, um, you know, simply speaking, increases the gap between energy requirements and energy production. So, like, one of the hallmarks of these acute brain injuries is a deficit in energy production with, you know, mitochondrial failure or mitochondrial dysfunction. And so if you get too hot or you stimulate the brain, you're asking for more energy when the, when the, when your neurons can't produce it, and that is a trigger. That kind of deficit in energy production is a trigger for cell death and neuroinflammation and some of these other processes that then may happen. So avoid alcohol. Avoid caffeine. Both of those potentially related to im- im- improving sleep. Then, uh, things that we have some, you know, reasonable evidence for, um, immediately after concussion are creatine.
- AHDr. Andrew Huberman
At what dosage?
- TWDr. Tommy Wood
The best trial was actually done, um, in a pe- like pediatric group, although very broad. It was, like, 1 year old to 18 years old. Um, but they gave .4 grams per kilo per day. So-
- 2:24:04 – 2:32:16
Treating TBI, Supplements, Physical Therapy
- AHDr. Andrew Huberman
For the non, uh, head injured individual, is there any reason to go back to the old loading protocols of taking 20 grams per day, putting it in a little bit of grape juice or something else to spike blood sugar for this very reason, that it could, um, augment the, the passage of creatine into your cells as opposed to drawing water into the gut? In the '90s we would take five grams of creatine four times a day in an ounce or two of pure grape juice.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
Um, and you draw a lot of water into your muscle cells.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
You put on, you know, it varies, but I ... for me anywhere from five to eight pounds of ... It's water weight, but it's mostly in the muscles.
- TWDr. Tommy Wood
Mm.
- AHDr. Andrew Huberman
It's not insignificant. It translates to big strength increases. I don't take nearly that much now. I just do the 10 grams per day.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
But is there any reason to go back to those, the traditional loading?
- TWDr. Tommy Wood
So if you're just, like, long t- like long-term creatine supplementation pro- probably not. Um, in this kind of setting I think a, a lo- you know, the, the evidence is for a, a loading style protocol, right? So for most people it might be t- 20 to 30 grams of, of creatine spread, spread across the day. You know, for, if anybody's just, like, taking creatine for other reasons I've ... you know, just a, a standard dosing protocol, I, I think is fine. Um-
- AHDr. Andrew Huberman
Darn, I thought you were gonna tell me I could get it to work that way. Yeah.
- TWDr. Tommy Wood
[laughs] So the-
- AHDr. Andrew Huberman
Yeah
- TWDr. Tommy Wood
... so, like, the, the ... Some of the studies that use traditional, like creatine monohydrate and look at creatine levels in the brain, they did use a loading protocol for, for a week.
- AHDr. Andrew Huberman
Mm.
- TWDr. Tommy Wood
And then you see significant increases in brain creatine. But in creatine having other effects on the brain, you know, potentially improving mood, improving, uh, memory in, in older adults, um, some of those benefits happen at just, like, a traditional creatine dosage. So you don't need to take massive doses. You don't need to take load- loading doses. You can actually see some benefits at, like, five to 10 grams. So that's creatine. So magnesium, so 400 milligrams once or twice a day. There have been some trials that have shown, um-
- AHDr. Andrew Huberman
What form?
- TWDr. Tommy Wood
Those studies actually use magnesium oxide surprisingly. Um, but I would probably use magnesium glycinate. Um, the ... It's very bioavailable. Um, athletes usually need a bit more glycine anyway But any bioavailable form will, will be fine. Then oma- omega-3 fatty acids. Um, the evidence is, is, is a little bit better for like, um ... There are now several studies in like America, in like, uh, collegiate American football players where they take, uh, a couple of grams of omega-3s every day and across a season you see, um, less accumulation of, uh, biomarkers of, of injury like neurofilament light that are circulating in the blood. So that's something that I would just take long, like longitudinally. If you're somebody who's at risk of a concussion, uh, because of your sport or your job, I would just, you know, take a, a reasonable omega-3 supplement just longterm-
- AHDr. Andrew Huberman
Mm-hmm
- TWDr. Tommy Wood
... 'cause we have some reasonable evidence for that. Then, uh, other things might become a little bit specific to, uh, the symptoms that you're experiencing. So if you have sleep issues then, uh, there's studies that have used, uh, melatonin and that's, that's shown improvements. Uh, branched-chain amino acids at high doses, uh, for sleep, and that's interesting because outside of TBI, high doses of branched-chain amino acids may actually impair sleep because they compete for tryptophan uptake into the brain, decreasing, potentially decreasing serotonin, melatonin, uh, production. But in TBI there are two studies that suggest improvements in sleep-
- AHDr. Andrew Huberman
Mm
- TWDr. Tommy Wood
... with high doses of branched-chain amino, amino acids.
- AHDr. Andrew Huberman
If somebody's going to take branched-chain amino acids, presumably they're gonna look at how much leucine is there for a variety of reasons. Um, so do you recall how much leucine to get this effect post TBI?
- TWDr. Tommy Wood
So I, I don't think they ... At least I don't remember the leucine dose, but they were taking up to 60 grams of branched-chain amino acids a day.
- AHDr. Andrew Huberman
6-0?
- TWDr. Tommy Wood
6-0.
- AHDr. Andrew Huberman
Okay.
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
'Cause a typical kind of suggested supplement bottle gym dose would be three to five grams.
- TWDr. Tommy Wood
Yeah.
- 2:32:16 – 2:38:51
Strongman Competition
- AHDr. Andrew Huberman
You're doing a strongman competition?
- TWDr. Tommy Wood
Uh-huh.
- AHDr. Andrew Huberman
All natural. This is not the enhanced games.
- TWDr. Tommy Wood
No. [laughs]
- AHDr. Andrew Huberman
Um, just tell us what the format of that is. Well, first of all, how old are you?
- TWDr. Tommy Wood
41.
- AHDr. Andrew Huberman
Cool. Have you done one of these before?
- TWDr. Tommy Wood
Yeah, I have six or seven competitions at, at this point. I started during COVID. I've done, like, a competition or two every year since then.
- AHDr. Andrew Huberman
Mm-hmm. You're a tall guy. You're, like, 6'2. You weigh?
- TWDr. Tommy Wood
Like, 210, 215 usually.
- AHDr. Andrew Huberman
And is it... Uh, so it's height and weight class or just weight class?
- TWDr. Tommy Wood
So it's, it's weight class.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
Um, I now... So now that I'm older than 40, I compete, uh, in the masters category.
- AHDr. Andrew Huberman
Mm-hmm.
- TWDr. Tommy Wood
So there's a... This is one of my favorite things about Strongman is that if you l- weigh less than 200 pounds, you're a lightweight. So I'm, uh, I'm in the lightweight masters category. It means that I usually have to, like, do a w- um, a water cut to, like, for, for a weigh-in 'cause I don't normally... I'm not, I'm normally above 200 pounds. Um, but yeah, they... So they have, they have weight, they have weight classes and age classes.
- AHDr. Andrew Huberman
Can you eat your way a- and hydrate your way back up to after the weigh-in?
- TWDr. Tommy Wood
Oh, yeah.
- AHDr. Andrew Huberman
Okay.
- TWDr. Tommy Wood
Like, the... Usually you weigh in 20 hours, 24 hours before.
- AHDr. Andrew Huberman
Okay.
- TWDr. Tommy Wood
I'm, I'm definitely back to my usual weight by the, by the next day.
- AHDr. Andrew Huberman
Gotcha. Yeah, we don't want you, uh, trying to lift heavy things dehydrated.
- TWDr. Tommy Wood
[laughs]
- AHDr. Andrew Huberman
What are the big events? Are you carrying stuff overhead? You carrying stuff at your sides? You're... What are you doing?
- TWDr. Tommy Wood
A standard kind of local regional competition is five, is five events. Um, I qualified for the natural, like, World's Strongest Man, uh, which is gonna be seven events, but there's usually, um, some kind of deadlift, some kind of overhead pressing event, uh, some kind of, um, medley where you're, like, carrying something, lifting stones, farmer's walks. So in, um, a truck pull, something like that, so, like, more dynamic. So there's, like, usually, like, a static max strength thing, but then also, like, more dynamic kind of-
- AHDr. Andrew Huberman
With the teeth?
- TWDr. Tommy Wood
Yeah.
- AHDr. Andrew Huberman
You, you do the teeth pull? The-
- TWDr. Tommy Wood
Uh, uh, no-
Episode duration: 2:41:26
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