← The mindbodygreen Podcast
The mindbodygreen Podcast
645: The truth about cognitive decline and what you can do about it | Tommy Wood, M.D., Ph.D.
00:43:58
Dr. Tommy Wood is a neuroscientist, Associate Professor at the University of Washington School of Medicine, and author of The Stimulated Mind. With degrees from Cambridge and Oxford, he has published more than 100 scientific papers and lectured worldwide on brain health, metabolism, and human performance. He also serves as a performance consultant to world-class athletes, including Olympians and Formula 1 drivers, and co-founded the British Society for Lifestyle Medicine.
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- [00:00]
A
Welcome to the MyBodyGreen podcast. I'm Jason Wakab, founder and co CEO of MyBodyGreen and your host. This podcast was created in sponsorship with Toyota. At MyBodyGreen, we believe in a well lived life is one you share with people you love. The right vehicle makes that possible. The 2026 Toyota RAV4 is built for all of life's moments, big and small. Need more room for the crew? The Toyota Highlander comfortably seats up to eight. For bigger plans, the Toyota Grand Highlander offers spacious comfort and smart storage. When family's at the center of it all, the Toyota Sienna brings flexibility to support every chapter. No matter where you're headed, the right vehicle turns travel time into together time. Learn more@toyota.com People are the destination. Most of us assume that cognitive decline is just part of getting older, something written on our genetics or our family history. But what if the biggest threat to your brain isn't your APOE4 gene or your amyloid levels? It's the convenience of modern life where we have engineered out every obstacle our brain needs to stay sharp. Today's guest is Dr. Tommy Wood, a neuroscientist at the forefront of brain health, cognitive decline and traumatic brain injury. He holds degrees from Oxford and Cambridge. And his new book, the Stimulated Mind, makes the case that the tools most likely to protect your brain aren't even found in a lab test. The found in how you move, how you eat, how you challenge yourself, and how you connect with other people. Wood opens up about the years he's spent letting a bad night of sleep ruin his next day and the best protocol he has found for maintaining brain health. What he found changed how he operates and I think it'll change how you think about performance too. Let's dive in. So testing has come such a long way in the past few years with regards to our cognitive health. And you know, we can do genetic testing and look, do we have the APOE4 gene? Do we have a double copy of the gene? We can do the, the blood markers, you know, P tau amyloid. And it's fascinating and interesting and I'm a believer that information is power and early intervention can be extraordinarily helpful and life saving. But the more I learn as it relates to cognitive decline and what we know about dementia and Alzheimer's, I kind of feel like we look at these things because they're measurable, but they may not be the most important drivers. You're the expert, you tell me.
- [02:39]
B
So I have a lot of hope that these biomarkers will become more useful over time. Of course, I want people to have as much information as possible and it to be actionable. I think that's the most important. The information is actionable. And that's where the gap really exists right now. There's been some very nice discussion about this in the academic literature. There was one paper called, I think it was the Tyranny of Biomarkers, which I really liked. And they made this point that we're developing these biomarkers largely because, A, they're things we can measure, and B, they're things that we could potentially modify with drugs, but they're not necessarily the things that actually matter when it comes to improving the treatment and quality of life and disease progression for the patient. So there's this disconnect between the biomarkers we're developing and what actually matters for the individual, and hopefully those things will align. But right now, you see lots of people testing these things, and we don't really know what to do. Like what's, quote, unquote, normal, what's benign, what do we do if a biomarker is elevated but you're doing everything right and you display no symptoms and, you know, have nothing really to be concerned about? And right now we just. We just genuinely don't know. So this will come over time. But I think that the. The thing that we can focus on right now is we know so much about the significant risk factors for cognitive decline dementia. We know that they're modifiable. We know that if we address those, we could potentially dramatically decrease dementia burden. And that's in the absence of having to test any biomarkers. But maybe we test these things and that makes people engage in these activities, right? They take their metabolic health more seriously, they take their physical activity more seriously, they take their sleep more seriously. That can certainly be useful. But I think we're still struggling to figure out exactly what are we measuring, what does it mean, how do we act on it?
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A
So in other words, testing P tau in a vacuum is not necessarily helpful.
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B
Exactly. Yeah.
- [04:35]
A
And so what do we know for sure in 2026?
- [04:39]
B
We know for sure, and this has really shifted over the last five or 10 years. And maybe it's even hard to say no for sure because these are sort of like statistical estimates based on best available data, and, you know, all that kind of stuff that we know from epidemiology studies. But we believe that a significant proportion of dementias are preventable, and the estimates differ from study to study. But it's something like 45%. That's Professor Jill Livingston's estimate from the Lancet Commission on Dementia Prevention. Other studies, like those work done by Professor Yin Tai Yu, They've used the UK Biobank to estimate that maybe more than 70% of dementias are preventable. And we're largely talking Alzheimer's disease and vascular dementia, which between them make up 70 to 90% of dementia cases. And probably about at least half of those preventable cases are due to modifiable factors, things that we can. Things that we can address ourselves. Smoking, alcohol, hearing loss, physical inactivity, obesity, high blood pressure, diabetes. So that gives us a lot of scope to very dramatically decrease our risk. And at the same time, and some of this actually requires appreciating studies that were done, you know, 50 years ago. We know that cognitive function, as people go from their 50s, 60s, 70s, into their 80s, most people actually maintain stable cognitive function, or it should be possible to maintain stable cognitive function into your sort of eighth, ninth decade. Like, we don't really kind of internalize that. We expect decline. And because we expect decline, we're less likely to engage in those things that I just mentioned as risk factors for dementia. So I think. So this combination of appreciating that this risk is modifiable, that there's things that we can do, and knowing that if we take those actions, we will expect to see much more stable cognitive function later into life than maybe we thought was possible.
- [06:35]
A
So I love the book. I encourage everyone to get it. And I think one of the things that really hit home for me is you really talk about lifestyle in a way which makes sense. And I would assume, or audience, you know, they're probably not smoking, they're not drinking a lot, like they're doing the basics. But I think the way you emphasize exercise, you know, in terms of cardio and strength training and muscle being the output, I think that's something a lot of people can get behind. And also this idea of not letting your brain rot, you know, in terms of the modern conveniences and over optimizations. But let's start with, with cardio exercise. If we are exercising for brain health, what does that look like? What is the minimum effective dose? All. All cardio is not created equal. Can you talk more about that?
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B
Yeah. So we see you're very much this sliding scale of cardio where any is great, but up, up to the point where maybe you're very, you know, very high volume endurance athlete, but up to, you know, excluding kind of those kinds of people who are maybe training 20, 30 hours a week, if you're, if you're training up to an hour or two a day, or moving for an, up to an hour or two a day, let's put it that way. More. More is more essentially. So we know that dementia risk increases particularly in those who, who have very prolonged unbroken periods of time during the day, being sedentary. And is the prolonged sedentary periods more than just being sedentary throughout the day? That's an issue because as you're sedentary for long periods of time, we know that blood flow to the brain drops, motivation drops, energy drops, some aspects of cognitive function can decline even within two or three hours just of just sitting completely still. So just getting up and moving around actually is enough to significantly offset that to just. And so I call them exercise snacks is the term in the literature, but it's basically take the stairs, do a couple of squats, just stand up and walk around. Breakup periods of being sedentary all day. Then from there, right, you want, you want to do some extended periods of exercise. And so we know that somewhere between 8 to 12,000 steps per day is where you see the lowest risk of dementia. But that increases linearly from like 2,000 steps a day. So if you're only taking 3,000 steps a day and then you make that 5,000 steps, that's a big, that's a big jump. Again, this is probably something that the listeners are hopefully doing. They're probably you getting, getting their steps in most of the time. It's interesting that you see that exercise, snacks and more sort of walking in steps are beneficial even in those people who are doing regular sort of structured exercise. So I used to think, oh, I go to the gym every day, I don't need to worry about my steps, I don't need to worry about sitting all day. But like, there's some interesting epidemiological data that actually you benefit from, from that additional low level movement, even if you are regularly exercising. Then we know that intensity does matter if you're trying to get the most out of your, out of your cardio. So probably the first one of the first studies that showed that you could actually increase the size of the hippocampus in older adults previously. So the hippocampus, really important for memory, is affected particularly in the later stages of dementia. We used to just think that it got 1 to 2% smaller per year once you're in your 60s and 70s. And if you got dementia, it's probably about the, the rate of decline is probably about double that and, you know, function kind of drops as the size of the hippocampus decreases. There was a study, now more than 15 years old, where they took relatively sedentary older adults and they had them do brisk walking. So, you know, if you're into your cardio zones, based on how they prescribed intensity, it was kind of, it was essentially zone two, 40 minutes of zone two brisk walking three times a week for a year significantly increase the size of the hippocampus, significantly improve fitness and improved memory. So if you're not moving much, just like walking three times a week has a significant effect. But one of my favorite studies that shows that even more intensity, maybe even better if you can do it, was published a couple of years ago where they took a similar age group, sort of 60s and 70s, and they, they had three groups. They're like a low intensity kind of, you know, stretching balance group. They had a, essentially a zone two group who did something very similar. So three times a week, 40 minutes of, of, of jogging on a treadmill. And then they had a high intensity interval training group who did something called the Norwegian 4x4 protocol. So if people aren't familiar with that, you run for four minutes, 85 to 95% of your maximum heart rate, they took a three minute break and they did that four times, four times over, hence four by four. And they did that three times a week for six months, which is a pretty intensive training regimen. But what they found was that in that group there were much greater benefits in terms of the structure and function of the hippocampus compared to the other two groups. So like, the zone two stuff was beneficial, but there was more benefit in the interval training group and that benefit was retained for at least five years. So, so they never do this in exercise studies, but they sort of let these people go back to their normal training and they tracked like they just went back to just doing whatever they were doing previously. And that wasn't different between the groups. But then they brought them back five years later and those benefits in terms of the structure and function of the hippocampus were retained in like there's benefit over, over in the, in the interval training group compared to the other two groups. So like, I mean, this is, this is just amazing that they did this study and they, they found this stuff. So there's something about intense cardio exercise that seems to have particular benefits for the brain. And you see across the cardio spectrum, across that intensity spectrum of cardio, cardio seems to be particularly beneficial for the Hippocampus and the gray matter of the brain and memory in particular in terms of cognitive function. So resistance training has different effects than cardio, but there's something about that high intensity cardio. And I think, and in this study they sort of measured certain things and they saw that like more cortisol released during exercise was actually better because it was like showing that it was more intense exercise. And that's important to bring up because right now like everybody's against intense exercise and cortisol because they think like, all cortisol is bad and you should avoid cortisol spikes as much as possible. But along with that cortisol spike, you're getting stuff like lactate. And so lactate goes into the brain, it switches on the production of brain derived neurotrophic factor bdnf, which we know is like miracle growth for neurons and neuroplasticity. So there's really something magic about that intense type exercise and the signals that those muscles then send to the brain.
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A
I mean, you're preaching in a choir. I just rode myself silly. You're. I think you're a rower. I think I rode myself right before this podcast. Intuitively it makes sense. Is there, in your view, are there certain. So I mentioned rowing, like rowing versus the skier versus running versus, like, does it really matter what the modality is? As long as you're really getting your heart rate up there and pushing yourself through exertion? Does it matter in terms of brain health or.
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B
No? No, I would argue that it doesn't matter at all. I think what happens when we talk about specific studies, which I, which I, which I do a lot. I, I admit we assume that that protocol they did in the study is like the protocol that we have to do, but there are so many studies on different types of interval training, cognitive function, cardiovascular fitness, all that kind of stuff. And so I would just say any modality where you can push yourself hard, you can feel the burn. I actually prefer things like rowing and cycling because if your form does start to break down a bit as you get tired, they're a bit more forgiving on that front. Whereas, you know, like on a treadmill, you know, if you're like really pushing and your form starts to break down like it can for some people, it can be, it can be a problem. So like, I really like the row machine cycling, but like, if you're, if you're a good runner, then the treadmill is great too. Skierg is great. The assault bike, another really good option. So, you know, you Work hard for somewhere between 30 seconds and a couple of minutes, and then you, you rest for a similar amount of time and then you do that again and you do that for 10 or 20 minutes like that. I think that's going to be enough for, for most people. I don't think you need to overthink it too much. It's just like really making sure that you're working hard, taking a good break. And you probably only need to do that, you know, maybe once or twice a week, because you'll get other benefits from other types of movement that you're sort of like building out throughout your week.
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A
Various age advice and even someone who pushes themself a couple days a week. On the rower, I struggle with the Norwegian protocol. I just, you know, I'm like, I. I just can't.
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B
It's hard.
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A
It is hard. And I, and I, I just, yeah, I'll create my own variation of it. Uh, but various stage advice. I like that. Just get your 10 minutes in. Push yourself. Don't overthink it. Something else you say which also resonates. You know, muscles come back in a. In a big way. Strength training, resistance training, I love it. I'm here for it. You say it's a. But muscle is a brain organ. This isn't just like aesthetics, body metrics, like, muscle is a brain organ. Let's talk more about that.
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B
Yeah, so you see this like very consistently now that muscle mass, muscle strength, and probably maybe even more so, muscle power. But strength and power are really important predictors of cognitive function, but also rate of cognitive decline. And I think there's. There's a few, a few different reasons for that. One is that your strength and power tell. Tell you something about how you interact with the world. Are you going out and moving and doing things and using your body? Because even just that will help you maintain some aspects of physical function. But equally like you say, like the muscles are organs and so they release these things, myokines, if they release from the muscle. But when you exercise, you release different molecules from other organs as well. So there's this like, big category of exokines. So like the liver releases things and the bones release when you stress them with resistance training or weight training, that can go to the brain and have beneficial effects. Your muscles are also your biggest glucose sink. So you see from studies that where people gain muscle, their blood sugar control improves because those muscles then become. They use up part of the sort of circulating blood sugar. So when you then look at studies where they have people do Some kind of resistance training. What you see, and again, in a similar demographic, so like older adults, if they lift weights twice a week for, you know, 30 to 45 minutes, they do a very basic resistance training program. So it's five to six different machines in the gym. But this could be bands, it could be dumbbells, it could be free weights, it can be machines. It just has to be hard work for you, whatever that is. Again, a study might do five to 50, you know, three sets of five to 15 reps. But we also know from the, from the, like, muscle building literature that it could be 20 or 30 reps. As long as you're sort of reaching fatigue at the end of a set. And you do that, you sort of across the whole body, twice a week, you see significant improvements in the structure of the white matter of the brain, which kind of sits in the middle of the brain. It's responsible for all our really fast connections and many of our most complex cognitive functions. Humans have more white matter in their brains than any other species. I think that's part of the reason why our brains functions as they do, you see. Yeah. So significant improvements in white matter structure and then function, particularly things like executive function, working memory, decision making. And so that's kind of the minimum effective dose, I think, ideally twice a week, 30 to 45 minutes. Hit the whole body. Basic resistance training program. Significant changes in brain function.
- [18:21]
A
So how much of it is. There's some level of thinking while you're also at the gym and you're doing these exercise, you're focused on form, you're trying to get your reps, you're thinking about hypertrophy. Like there's, there's, there is some brain function happening and then there's actually, you know, the byproduct of building muscle. It's protective, allows you to, you know, absorb glucose perhaps a little bit better, helps you move in the world. Like, how do you think about all? Like, what is so magical about muscle as it relates to our brain and, and resistance training, the, the, the, the practice of it.
- [19:00]
B
So this, this is the funny thing, and it's something that I kind of focus on quite a lot in the book, especially the early part when I try and talk a little bit about the history of neuroscience and where we have and haven't gotten in terms of understanding the brain. And we always have this tendency to ask our scientists, like, why does this, why does this work? Right. What's the, what's the mechanism? And so when I apply for government grants to do research in the lab, I wouldn't get funded if I didn't say we're going to figure out exactly how this thing works in the brain and we develop therapies for brain injury. But I think the things that have the biggest impact in terms of cognitive function, dementia risk, they do a whole bunch of things. And some of those we don't even know yet. There's actually at least once or twice a year, every year there's a fancy paper in a fancy journal, Nature or Science, and they're like, hey, we found this new molecule that gets released during exercise. Are all the cool things that it does, right? So we don't even know how exercise works. We know a little bit of how exercise works. We don't even know how exercise fully works. So I think that all the things you mentioned are a big part of this. The act of really controlling your body against resistance, that's a neuromuscular stimulus. You're training those pathways and stimulating them. Plus you have to be just engaged in that process. You're having to focus, pay attention. And that's increasingly hard nowadays. So anything, anytime you spend just focusing on something right is going to be beneficial. And then you release a whole host of factors. And I think one, one of the reasons why I think this One particular factor, IGF1, is critical is because of where resistance training seems stacked in the brain. So we know that when you do resistance training, you increase IGF1 levels. IGF1 levels tend to decline with age. Lower IGF1 is associated with a higher risk of dementia, but throughout the entire lifespan. And this includes some of the stuff that I do early in life in my neonatal brain injury. You see that IGF1 is critical for the development and function of the white matter of the brain. So I think that's kind of, that, that's a, an important tie between resistance training and, and, and white matter structure. But I think all the other things you mentioned play a big role as well. And if we can spend our time focusing on these different interventions that do a whole bo a bunch of things at the same time, that's why we get. Well, I think that's why they give us such big bang for a buck.
- [21:26]
A
This podcast was created in sponsorship with Toyota. Think about the last time a simple plan turned into something memorable. A spontaneous dinner, a group workout, a weekend escape. Those moments usually start with someone saying, let's go. Toyota makes vehicles built for these moments. From the up for anything Route 4 and a family friendly Sienna to the adaptable Highlander and the Ultra Spacious Grand Highlander explore a lineup that's designed for real life. So every single day is an opportunity to make more memories. Visit toyota.com People are the destination. Yeah, makes a lot of sense. How do you think about nutrition? If I want to take care of my brain and building muscle and.
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B
Yeah, so the, the way that I think about it, I have essentially like three, three levers or three interacting aspects of diet that I, I sort of talk about. So the first, which is, is really critical, particularly in the modern food environment, is, is just energy. It simply is like total amount of calories. And particularly when you're talking to audiences who are like focused on longevity, athletic performance, this is an important thing to focus on because basically there's like a bell shaped curve between brain structure and function and energy status. So at the high end, right, we see cardiovascular disease, we see metabolic disease, we see obesity and we see smaller brain volumes, higher risk of dementia, faster cognitive decline. So you can become, I call it excess energy availability, but it's almost like some degree of energy toxicity because the body's energy state is dysregulated. That's essentially what metabolic disease is. And that's definitely associated with an increased risk of cognitive decline, dementia. But at the low end we see the same thing. So individual. Like when I work with athletes, it's very common for them to have something called low energy availability or relative energy deficiency sport where you basically, you're not consuming enough calories to do all the work that you're doing, to do all the training that you're doing. What you see in those individuals is problems with sleep, problems with mood, problems with cognition, focus, attention. Their brains stop working as well because they're just not getting enough energy in. And when you look at some of the big population studies they've done, those who have low energy availability also have smaller brains and that probably translates to an increased risk of dementia as well. So in the kind of world where we're often told that actually, oh, like lots of restriction, intermittent fasting, caloric restriction is beneficial. I think that is beneficial if you started off life at the other end of the spectrum. Absolutely, we know that. But we know because the brain is so energy hungry, we risk starving our brains if we're not getting enough calories in. So finding some kind of sustainable part of that energy spectrum is important. Then the next aspect is nutrients. We know that there are nutrients that are very closely tied to dementia risk. And if we supplement with them, if we're not, because we're not getting enough from the Diet we see significant improvements in cognitive function, brain structure, etc. I like to call nutrients like the great leveler of nutrition because you know, everybody is going to argue should it be plant based or carnivore or keto or Mediterranean or everything in moderation. And I think that as long as you're hitting your energy needs and you're hitting your nutrient needs, the rest matters a lot, a lot less. So we're talking B vitamins, particularly the B vitamins associated with methylation. So B12, folate, B6 and riboflavin, we're talking omega 3 fatty acids. Then iron is really critical. Vitamin D is really critical. We see things like magnesium and zinc, some of the antioxidant vitamins, vitamin C, vitamin E and then antioxidant polyphenols and related compounds seem to be associated with a decreased risk of dementia. Plus if you look at the brains of people who have dementia versus those who don't, those who remain cognitively intact until death have higher levels of some of these compounds in the brain. So that's like lutein, zeaxanthin, astaxanthin, that make things kind of yellow and pink. So seafood, but also. Yes, these are the carotenoids. So peppers and carrots and things like that. And then things that make foods kind of blue or purple or slightly brown. So what you find in coffee and tea, the anthocyanins in berries, lots of randomized controlled trials of berries showing both immediate and long term improvements in cognitive function. So those kinds of things play a big role as well. Then you might get other aspects like choline important is like a, yeah, important sort of structural compound in the brain. So we know there are these nutrients that are critical, we know that energy status is critical. So then the third part of my, my sort of diet framework is, is pattern, which is essentially just hat a sustainable way that you could eat. So you achieve those two other things and yes, then it could be a Mediterranean diet or the mind diet, which is like a Mediterranean diet for your brain health has some interesting evidence for it, but you could do it in any dietary pattern as long as it's sustainable for you and you're achieving those, those two other goals.
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A
On the subject of supplements, what's your view on a lot of the developing science around creatine and brain health?
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B
Creatine is something that I take every day and I have for a long time as an athlete. I think the, the data on brain function and brain health of creatine is really, really interesting. We're Definitely not at a point where we could say it's going to be preventing cognitive decline. Though when you look at across all the different randomized controlled trials, it seems to particularly benefit those who are already experienced, who are either older or are experiencing some element of decline already. And it particularly seems to improve memory. That's the function that it seems to benefit the most. But we also have evidence that even at sort of standard doses, 5 grams, it might improve treatment in depression, improve depression symptoms. There's been a lot of focus recently in sleep deprivation. So there's one study that came out very recently showing that a high dose of creatine sort of helped maintain function during a night of sleep deprivation. But actually there have been studies going back more than a decade that showed the same thing. So there was a study in rugby players now in the sort of like 2000 and tens where they had that they were sleep deprived and then they looked at sports specific skills the next day and showed that again, even just like lower doses, 5 to 10 grams of creatine significantly helped to maintain some of the offset in sports related skills that they saw with sleep deprivation. So and then the final thing is I do some work in traumatic brain injury and concussion and there's a pretty good amount of evidence that creatine may be beneficial there. Probably maybe more beneficial if it's on board beforehand rather than afterwards. But even afterwards, especially in pediatric concussion, there's some evidence that it may improve recovery. So lots of interesting things about creatine and the brain. I think that's only going to increase over time as people sort of become more interested in it.
- [28:19]
A
I agree. After we get off, I'm going to have to send you our creatine brain, which is 5 grams of creatine monohydrate with 500 milligrams of cognizant, which is
- [28:28]
B
branded C. Great, great, great combination.
- [28:30]
A
Yeah, I'm going to send that to you. We'll offline about that. So the other thing I love about your approach and the book, it's this idea that, you know, modern convenience and over optimization or retirement isn't exactly helping our cognitive health. I think about the drive where I'm on a GPS versus you know, the famous London cabbie study where being a cab driver in London is like the most complicated. Tens of thousands of streets to memorize. These guys have like no shrinkage in their hippocampus. I think about us gps everywhere. I think about AI now I think about just not this idea. You talk about this like mistakes, challenges, these are Amazing for cognitive health. But we are in a world where there's, it's just too easy maybe.
- [29:22]
B
Yeah, I think we're, we're now in this, in this sort of third stage of convenience that could have a really significant impact on brain health. So like the first two people are going to be familiar with, right? So we've managed to engineer all movement out of the environment. We don't need to move if we don't want to. Right. So we've had to invent exercise and then we engineered the food environment so that we could have super convenient, hyper palatable food that was easy to over consume. So we've had to invent diets and you know, those, those, those foods tend to be nutrient poor. And now we've gone to the point where we don't need to use our brains because everything will do it for us. And then as a result we're going to have to invent ways to, to really stimulate and engage our brains or not necessarily to invent them. We know what we can do. We just actually have to, have to, have to do that. And you know, some of this is, you know, particularly when you talk about mistakes and errors. So mistakes and failure and errors. They're all essentially different versions of the same thing. Or if not the same thing, they're essentially the primary drivers of neuroplasticity. So neuroplasticity being this process where the brain makes new connections. And when you learn new skills, you can see the structure of the brain change. You see that in the London cabbies as they learn the knowledge. 25,000 streets in Central London. You see it in people as they learn how to juggle. You see it in people if you teach them a new language or a musical instrument. And this is like neuroplasticity. So part of it is just new connections between neurons, but then there's all the other like stuff. As neurons only make up half the cells in the brain and there's all these other cells and then there's the blood supply and the structural proteins and all these things, all of that can change in response to, to how we use our brains to help build both structure and function. And in the sort of like modern environment we're trying to engineer out mistakes first in like the education system where you teach kids like it's bad, it's bad to be bad at something, right? You don't want to, you don't want to fail. And then as adults we kind of take that as well. Like we hate to do stuff which we're bad at, especially if other people see us be bad at it. Like, that's why you don't go to the language class or the dance class. And I've done this myself. Somebody once signed me up for a dance class and I flat out refused to go because I felt so uncomfortable about how bad I was going to be at it. This is now more than 10 years ago, and I regret that that was my, that was my response. But like this, I understand this feeling. So when there's a mismatch between what you want to do and what you're actually capable of, the brain is constantly monitoring for that. That's what mistakes are actually. So your brain is trying to do something, it expects something to happen and then it doesn't happen. And then that kind of gets all the machinery going to say, hey, we need to make some changes to kind of close that gap between what we wanted to happen, what actually happened. And so this is why engaging in like cognitively challenging tasks, engaging in new skills, making mistakes, getting better, improving over time, these are what, these are the things that drive capacity building in the brain. And it's just like physical activity, right? You go to the gym, you lift something, you reach failure, you do that over a period of time, you get stronger, you can lift more, you can do more reps. And the brain is essentially the same.
- [32:38]
A
So what do you recommend in terms of your protocol? Okay, we're doing our resistance training at least twice a week. We're doing our, our VO2 max cardio maybe once or twice a week. What does this look like in terms of brain stimulation? Is it a crossword? Is it a, is it reading? Is it a pocket? What does that look like? What should everyone do?
- [32:55]
B
Yes, so there's, there's a few different ways to, to think about it. And again, look, kind of largely driven by, by how it's been studied. But you know, people who, who develop expertise in some kind of either complex skill or, or creative art seem to have sort of younger looking, better functioning brains and a lower risk of dementia. So there's, there's going to be like some bas. So we know that people who have more complex jobs, right, they're less repetitive, they involve problem solving, they involve more social interaction, they tend to have slow cognitive decline as well. And so there's going to be just like the day to day, are you regularly, you know, ideally every day engaging in stuff that uses your brain in some way, problem solving, interacting with people, sort of learning new skills at work, whatever that might be. And so as Much of that. And that's kind of like, that's like in our cardio example, that's like the walking, right. You just need to, that's kind of your low level activity. Continuing that is going to be important. But then you also want to do some higher intensity stuff. So this might be, you pick one skill that you're bad at and you do it two or three times a week. Because we see that the most efficient in terms of amount of learning you get from a single bout of learning or the amount that you retain from a single bout of learning is maximized if you're doing it every two or three days. You can learn faster if you do it more frequently. Just like you'll, you'll get fitter if you exercise more frequently. But in terms of people who just have a limited amount of time, pick some, pick a language, musical instrument, a sport, you know, dancing, pickleball, and then do it two or three times a week for maybe like an hour. And that's going to be a really good framework to start. It's going to be relatively time efficient, relatively challenging, and it's going to give you a good progression. That's going to be sort of like building some of those, you know, building some of those capacities.
- [34:49]
A
Love it. It also feels like we're underestimating social connection. Real world conversation.
- [34:54]
B
Yeah. So I, a couple of years ago, maybe it's 2022 now, a colleague of mine, Dr. Shosh Turk, he's a neurologist and we have a podcast together, we've written papers together and we wrote a paper about this idea that how we use our brains really determines how they function late in life. So by not using them in the same way, by removing stimulus, we then drive a functional decline that we call aging. But it's really just, it's a product of how we've changed the way we use our brains as we get older. And I spoke to a friend of mine about this, a guy called Julian Abel, he's a retired palliative care physician and he's done some really groundbreaking work in compassionate communities, like building building community connection in a town that then significantly improves the health of that, of that town. And he's published these data, it's now been replicated in multiple cities around the world. And I sort of explain this idea of stimulus driven decline or like the lack of stimulus driving decline. He was like, yes, that's true. But this is all really driven by humans need for social connection. Because most like most of the times when we're learning Complex skills. Most of the time we're express complex skills. Most of the times when we're, you know, learning and doing things, it's in the context of other people. And our social brains are really significant drivers of how our brains developed. So yes, I think just the process of being out in the real world, learning and doing things with other people is a critical component of all of this. And it's also a critical reason to do all of this because there's very few people who, you know, want to live to be 100 or longer with their cognition intact. And actually most people just want to have their cognition intact even if they just live to be 80. Right. Very few people want to do that just so they can sit at home like feeling smart. They want to do it so they can continue to, like, connect with loved ones and spend time with them and remember that. So I think that our social brain is really a big driver of this requirement, but then also the, you know, the reason to do it in the first place.
- [37:04]
A
So if you could wave your magic wand and get funding for any study and it could just happened, happen tomorrow,
- [37:11]
B
what, what would you do?
- [37:12]
A
What would you love to see?
- [37:14]
B
I'd love to see a large scale, practical version of some of the, you know, more advanced kind of interventional studies that we've seen in cognitive function. So, like, there was like recently published this sort of precision medicine approach, or it's actually not published, it's published as a preprint. But Dale Bredesen's like, precision medicine approach to cognitive decline and their results, they haven't been formally published yet, but they look very impressive. So people are already experiencing decline, seeing reversal of that. So one study that I would want to see is how do we apply this in a practical manner at scale? Because a lot of the stuff that they're doing in that study is going to be really hard. The test, all the testing and supplements and all these kinds of things are just going to be really hard to scale when we know that what we could potentially layer on is more community connection and community aspects of physical activity and volunteering, plus a little bit of targeted supplementation. Right? So we do some comprehensive blood tests and we give people blood pressure medication if they need it, and we address their cardiovascular risk factors and we give them B vitamins if they have high homocysteine and this kind of stuff. And so it's kind of like a middle ground between studies like Pointer, which people may have heard of. So that was this big study that was published last year. Older adults at risk of cognitive decline. They had them do improve their diet, improve physical activity. They did cognitive training, they did cardiovascular risk monitoring and they saw significant improvements in cognitive function over a, over a control group. It's kind of starting with that kind of idea, but then layering on some of these other things like social connection, maybe some more targeted supplementation if needed. But the real critical component though is having some kind of really long, long term view. So I mentioned earlier, right, that exercise study, bringing people back five years later is really unusual. And this is why we don't understand, don't know that much about the long term trajectory of some of these interventions because we like, we measure at the end of it, like, oh yeah, it improved. And then people go out into the world and we never see them again. So this is big and complex, but I think this is kind of what we need to do, particularly if we're going to try and get physicians and insurance and stuff to kind of get behind some of this. Because I think that's going to have to happen as well if we want to see like change at a societal level.
- [39:29]
A
Makes sense. I'm curious, in writing the book, did you change anything personally in your own protocol where you said, hey, maybe I should be doing more of this or less of that?
- [39:38]
B
Yes. The main thing that really landed for me and has, I think has had a big impact was in the run up to writing the book, having spent so much time working with elite athletes, biohackers, optimizers, the sort of people at the right, at the leading edge of some of this stuff, which has pros and cons because sometimes you end up spending a lot of time and money on something that just doesn't matter because we don't have enough data on it yet. I'd gotten to this point where I felt like the goal of optimization was becoming problematic because people get so focused on the optimal number from their wearable, the optimal number on a blood test that they forget why they're doing it in the first place. You're hopefully doing it to live a long and in like an enriching life. Right. And so you have like people who are missing out on parties and birthdays and spending time with family because they're worried they won't get to bed at the right time. Right. I think that becomes slightly counterproductive. But like one way that, that really impacted me was for several years, I would think, and my wife will tell you she experienced it, like if I didn't sleep well, I would not perform well the next day. I'd be like really grouchy, I'd need my coffee and then extra coffee. And it would kind of get in my head like I hadn't slept well. And because I hadn't slept well, I wouldn't perform well. And you see from a bunch of really interesting studies that if you manipulate how somebody thinks about how they slept, they will feel worse, they'll feel more tired and they'll perform worse regardless of how they actually slept, right? And then you can see other studies where they have people and they sleep, deprive them and they look at their cognitive function. And yes, don't get me wrong, sleep is critical to brain health and long term cognitive function. But in the short term, the brain adapts and you see that processing may slow down a little bit, but quality of work and accuracy doesn't change. So you become a little bit more deliberate. You're a little bit grumpier about it. So like mood. So mood declines a lot more than performance. In reality, the performance decrement is negligible, if not zero, after a night of poor sleep. And so now I think that if you. Because I have the big rocks in place, right, usually I sleep well regularly and I eat well and I exercise regularly and I have good social connection. I spend time outdoors and all that. I've built an environment that kind of provides buffer in the system headroom, as I call it in the book. And then now I know if I don't sleep well, I'll actually perform just fine. And because I think I will perform just fine, I do. I do perform just fine. So what I worry is that when we get so worked up about getting everything perfect, we actually create fragility because then if things aren't perfect, we think we won't perform well and we don't perform well as a result. So that was something that really just seeing the data, seeing hard data being like, you know, actually after a night of poor sleep, your brain just is fine, you'll be all right. That kind of stuff actually made a big, made a big difference for me.
- [42:46]
A
We're on the same page. I think wearables are great, but if you wake up and see yourself in the red and then mentally say you're, hey, it's going to be a rough day, it's going to be a rough day. But if you say, ah, you know what, I'm going to go at it like, let's go, you're going to be fine, you know, so very well said. I love the book. It's called the Stimulated mind, encourage everyone to pick it up. Tommy, such a. Such a pleasure. Thank you so much.
- [43:09]
B
This is fantastic. So, so nice to be here and meet with you and get to speak about this. I really appreciate it.