The New Science Of Preventing Dementia: Protect Your Brain, Boost Your Focus, Resist Cognitive Decline with Dr Tommy Wood #638

We expect a certain amount of decline as we get older. And if you expect decline, then you embody this idea that you will decline, and therefore you stop doing the things that prevent decline, and therefore it becomes a self-fulfilling prophecy. But the first thing we have to realise is that there is this huge possibility to enhance function, physical function, cognitive function, at essentially any age, as long as we engage in these skills and challenges, we can expect that most people will maintain function later into life. Hey guys, how are you doing? I hope you're having a good week so far. My name is Dr. Rongan Chatterjee, and this is my podcast, Feel Better, Live More. If you think about getting old, one of the issues you might fear the most is dementia. Perhaps you've seen family members suffer, and you're worried it's written into your DNA. And whilst that quiet fear is totally relatable, did you know that around 70% of dementia cases are thought to be preventable? That is the astounding news that my guest, Dr. Tommy Wood, brings to this insightful conversation. Tommy is not only one of the doctors I respect the most, he's also a neuroscientist, brain researcher and performance coach who works with many of the top Formula One drivers. And he's back on my podcast for his fourth appearance to celebrate the publication of his first book, which, as you might expect, is absolutely brilliant, The Stimulated Mind, feature-proof your brain from dementia and stay sharp at any age. In this conversation, we talk about why your expectations around aging matter more than you think. We also explore Tommy's 3S framework, stimulate, supply and support to ensure that your brain thrives today and for decades to come. We discuss why it's so common to feel tired, but why it's at the end of the day, how different types of exercise help our brain, why we need to think differently about women's brain health compared to men's, and how regular social media use can stealthily undermine your well-being. Tommy has worked with Formula One drivers, elite athletes and everyday people, yet still, his learned practical advice comes back to one thing, keep it simple. It's much easier than you think to help your brain thrive at any age. It's never too late and every single thing you do counts. So sit back, relax and enjoy. In the new book, you state the 45 to 70% of dementia cases may be preventable. You also state that when you say that to people, there's often disbelief and or resistance. Where does that statistic come from and why do you think so many people push back at it? That statistic comes from two separate studies. 45% comes from the Lancet Commission on Dementia Prevention Report. There have been two now. The first was in 2020, the most recent one was in 2024. They upgraded the number from 40% of dementia is potentially being preventable to 45%. The 70% number comes from a study using UK Biobank data performed by Professor Yinti Yus Group, and they looked at all the different modifiable factors and risk factors for dementia to estimate. If we removed all of these risk factors from the population, what proportion of dementia will we expect to no longer happen? This is essentially what the Lancet Commission Report does as well. They have these statistical ways of estimating how much a given risk factor translates to a proportion of dementia in the population. It is an artificial way of doing it because we know that risk factors to any chronic disease are not a one-to-one thing, right? And people often have multiple risk factors together and they compound and they interact. But that's the best way to truly estimate right now how different aspects of the environment and society impacts dementia risk. So it's things like 7% of dementia are thought to be preventable if everybody got access to high quality education and high levels of education and attainment. And then there are risk factors related to smoking, head trauma, obesity, hearing loss, etc. And the 45% number from the Lancet Commission Report, I think that could be conservative because they didn't include things like poor sleep, which we know is a risk factor. They didn't include things like late life cognitive stimulation, which we know is important as well. So that's why potentially this 70% could be the upper limit, perhaps, of dementia that are preventable. But you're right that when you say something like that, first of all, people are surprised. I think this is new information. And then, especially those who have some kind of relationship with dementia, they have a loved one or family member with dementia, they have a family history of dementia. If you say that dementia is a potentially preventable, they might interpret that as if there's some blame on an individual who previously suffered from dementia or was currently suffering from dementia when that's absolutely not the case. We've just said that we're only just starting to appreciate that dementia may be preventable or a certain proportion of dementia may be preventable. Certain types of dementia may be preventable. And we know it's very complicated. Multiple risk factors may come together on an individual, genetic risk factors, environmental risk factors. And I truly believe that each person is doing the best with the information that they have and the things that they can do at the time. So it's more an idea of hope, right? Should we be able to modify our environment? Should we be able to make societal change to remove some of these risk factors? Because some of them are related to socioeconomic factors. There is the possibility of dramatically decreasing dementia burden in the population. And yes, individually, we can take that on and decrease our own risk of dementia. But it's really sort of an idea of what's possible rather than saying, oh, because somebody got dementia, they did something wrong. Yeah. It's that whole thing about blame. It's something I think a lot about on the show because each week we're trying to empower people with the things that you might be able to do in your own life. It doesn't mean, though, that if you get something, you failed in some way. Do you know what I mean? It's a tricky one, isn't it? It's also hard for us to think about this as individuals because we're talking about probabilities, right? So it would be impossible to say that any individual case of dementia is preventable. It would be very possible to say, were you to address certain risk factors, you will decrease your risk of getting dementia. But I could never say I can guarantee that one individual won't experience dementia. They may experience it later. They may have less of a decline, fewer symptoms. They may not experience it at all. But it's sometimes hard to wrap our head around the fact that when you're talking about statistics, you're talking about probabilities rather than certainties. And often in the health sphere, we're sold certainties and black and white stories. And it can be difficult to understand that there's some nuance in what we're trying to get across and what we could potentially do. I think those statistics, firstly, they're very empowering, but I think they're empowering on a couple of different levels. I think, firstly, it means, oh, wow, just because mum had it, maybe it doesn't mean that that's my fate. And so, oh, let me learn more to see what I can introduce into my life. So I think it's hopeful on that level. But I think deeper to that, it more broadly, to me, speaks to our collective attitudes towards aging. Are we expecting our brains to get slower, weaker, poorer, whatever that might be as we get older? Or do we actually think that that doesn't necessarily have to be the narrative? And, you know, in the new book, The Stimulates in Mind, you very clearly make the case that that does not need to be the case. Let's talk a little bit about mindset and attitude to aging, because I think that's quite key, isn't it? Yeah, I think so. And this is something that we've embodied as a society almost, that we expect a certain amount of decline as we get older. And I lay some of this blame at the feet of Sir William Osler, if anybody's heard of him, he's a very famous physician. He was a Canadian physician, helped to found Johns Hopkins Hospital in the U.S. and then he was a professor of medicine at the University of Oxford. And in the early 20th century, Osler helped to popularize the idea of retirement, because before then, other than sort of like military pensions, it wasn't normal for people to retire. He gave this famous address at Johns Hopkins where he said that at the age of 60, the average adult is useless and should be put out to pasture. And this then is something that we have internalized as a society, and this is essentially what we expect. I will give him a little grace by saying that at that time, average life expectancy in the U.S. was in, you know, late 50s. So maybe he was right that once you were 60, you know, the average individual wasn't in great health. But that's no longer the case, right, with the advancement of medicine and everything we've been able to do to extend both lifespan and health span of the population level. And despite that, I think we expect some level of decline. And because of that, we do things or stop doing things that then make that inevitable. So there's this idea of stereotype embodiment theory based on some of the work, including like Ellen Langer's work, you know, you know her work well. She's great. And she talks about the fact that if you expect decline, then you embody this idea that you will decline and therefore you stop doing the things that prevent decline, and therefore it becomes a self-fulfilling prophecy. So if we expect to lose physical function, we expect to lose cognitive function, then we stop doing the things that help us to maintain function. Oh, I'm too old to learn a new language. Oh, I'm too old to pick that up. Oh, you know, I might get injured. I don't want to do that. And we stop doing those activities that challenge our physiology, which are inherently the things that help us maintain function. And as a result, we see decline. So I think the most important thing to realize, and we can certainly go into the evidence that decline doesn't have to be inevitable, but the first thing we have to realize is that there is this huge possibility to enhance function, physical function, cognitive function. Essentially any age, as long as we engage in these processes and skills and challenges that help that to happen. Yeah. When I think about how our attitude influences the reality of our lives, I think about two cases or two sort of examples where there are some South American tribes, running tribes where you grow up from what I understand with the belief that as you get older, you get faster. Yeah. Right. And look, I haven't seen the physiological data, I haven't seen the VO2 maxes that they've measured or not measured. But apparently in your 60s and your 70s, they are the fastest runners. Right. And it, you know, we can look at the science, go, yeah, but we know you lose muscle mass from the age of 30. And we know that this is going to decline, right? Or whatever it might be. And also let's also not forget that if you grow up in a culture where it's believed that you get faster as you get older, how much of an impact does that have? Yeah. There's also some research I saw where if you live in a culture where older women are looked up to, right? And they're really valued. I think in some of those cultures, they have less reporting of menopausal symptoms. Now, I'm sure there's multiple complexities there. You know, are they reporting them on Earth? Are they, are they doing them the same way? Whatever it might be, I just find this whole idea that our mindset and the influence it has. And of course, L. Langer's work is hugely saying your mindset is massive. It's kind of interesting, isn't it? Yeah. There's so many examples of how what we think and what we expect drives our physiology as well as driving our behavior. And then essentially creates the reality that we expect. And you can measure this in many different ways. And, you know, L. Langer's work is critical to that, be that, you know, manipulating how people think about their sleep, then affects how they perform the next day, regardless of how they actually slept, or manipulating clock time and, or how people think about the food that they ate, which then affects their blood sugar responses to it, even if, you know, it's a standardized meal under different conditions. And so we know that what we think drives physiology as well as behavior. And then you sort of get the outcome that you expect to a certain degree. And therefore, I think we need to understand that this doesn't have to be the case when it comes to cognitive decline in people. And there's a few different ways that we can approach that. But the first thing, if people think about cognitive function, you think about a graph, right? So on one side, you've got cognitive function, like on the y-axis on the left-hand side. And then along the bottom, you've got age. And everybody might expect some, they've seen some curve where, you know, if peaks around your 20s or early 30s, this is like exactly the same with physical strength and muscle mass. And then sort of just like declines from there. And then eventually at some point, you'll lose enough function that you might reach a threshold that we call dementia. When you're doing those kinds of studies that result in those kinds of graphs, what you tend to do is you just sample a whole bunch of people, maybe thousands of people, and you measure their cognitive function. And you see that on average, yes, as you get older, the function is lower, right? You add up everybody's cognitive function divided by the number of people, right? You get the average. And yes, some people, as they get older, do lose function. So there are people who are sort of dragging the average down. But asking what the average function is or the change in function in an average population over time is not the same as saying, what's my function going to be in 10, 20, 30 years time? And so when studies have looked at that, there was a classic study. I think it was one of the first studies to do this. It was called the Seattle Longitudinal Study run by Warner Shieh. And he took individuals starting in the 50s. And he measured their cognitive function every seven years for multiple decades. And every seven years, he would bring back the old participants and add new participants. So in the end, he had data from people in their 20s up to people more than 100 years old. And what he saw was that the majority of people, so like more than half of people, maintained cognitive function into their 50s, 60s, and 70s. So yes, there were some people who lost function. They dragged down the average, but the norm, more than 50% of people, was to maintain function over time, even in your 70s and 80s. And those data were actually used to raise the retirement age in the US, because he showed actually that we can expect that most people will maintain function later into life. But if we don't understand that as individuals, then all those things we just talked about come into play, because we stop doing the things that help to maintain function, because we expect function to decline as we get older. I think about that through the lens of public health messaging. And let's take what you do or what I do on this podcast. You try to share information that people can then absorb, and then if they choose to, take on in their life. But there's a fine balance, isn't there? Because if you spend two hours talking about the problems of sleep deprivation, on one hand, you're being honest, you're trying to educate people, but also you're also probably infusing this idea that it's really, really bad. And actually, as you beautifully write about in your book, you know, we're pretty resilient. You can deal with a couple of nights where we don't sleep. But I've changed my messaging around sleep over the years. Let me put it, I've evolved it, because I've realized actually that when you do these deep dives, it's great, and for many people, it's like, wow, I better start taking my sleep seriously. But then you obviously get new parents who then send me messages saying, I'm really worried after that last podcast, you know, I haven't slept well for the last three months because my young baby needs feeding through half an eye, etc. And then the unintended consequence is you're trying to help and empower people, but sometimes that same message can be very disempowering and frankly quite stressful. Yeah, there's, so that particular example, there's a study that I referenced in the book that showed, this is using UK Biobank data again, showed that the more children that parents had, both men and women, the lower their risk of dementia. And I thought this was fascinating because on the face of it, having kids should be devastating for your cognitive function, right? Stress, sleep, you know, all these things that you don't get to do, you don't get to look after yourself anymore because you're so busy worrying about this new human. That now has to navigate the world. But this is what happens when we focus on the downside, right, downside of stress, downside of poor sleep, downside of, you know, what are the, you know, contaminants in seafood or is your food organic or not? In general, so many of these things, the benefits massively outweigh the downside. So when you think about kids, right, they come with opportunities for joy, cognitive stimulation, social connection, pro-social behavior, which is just such a critical component of humans and their evolution and what it takes to make them healthy, you know, looking after other people and, you know, building a community. And so those benefits seem to massively outweigh the potential downsides. And like this is then, I think the important thing for us to remember, A, we are incredibly resilient and adaptable and B, usually the things that we're doing want to try and get the most benefit out of them as possible. So when we're then worrying about those minutiae, the potential downsides, we're actually offsetting some of the benefits that we're getting from all these amazing things that we're doing. And I think a study that maybe we've talked about previously, but it's worth bringing up again, is a study where they looked at physical activity, both actual physical activity and perceived amounts of physical activity. This was done by Ali Akram, who actually trained with Ellen Langer, and now she's a professor at Stanford. And what they found was that people who felt like they were doing less exercise than people like them, you know, similar demographically, they had a higher risk of mortality. And there was another study that found a similar thing for cognitive function. So if you thought you weren't doing as much exercise as people like you, they ended up having, you know, on average, lower cognitive function. And this was after adjusting for how much exercise people were actually doing, as well as a whole bunch of, you know, health-related confounders. So what that says is, if you spend all your time thinking, I'm not doing enough, I should be doing more, you are then essentially creating a situation where you're not getting benefit from the things that you are doing, and creating this chronic stressor that's having negative health effects. So I'm much more in favour of celebrating all the amazing things that we do do, because those are probably offsetting any of the sort of like the minor things that we would otherwise worry about. Yeah, and of course, in the modern age now, we'll maybe talk about modern technology and social media later, but one of the things, of course, that many of us have experienced is comparison, right? And so, you know, maybe 100,000 years ago, you're kind of comparing yourself to your tribe. Yeah. Maybe 150 people max, maybe less, who knows? Now, we can compare ourselves to the best in the world at anything, right? So you go for your 30-minute walk around the block, but then you go on Instagram and someone's just done an ultramarathon, right? And so, you know, your 30 minutes around the block is fantastic for your mental wellbeing, your physical wellbeing, emotional wellbeing, your stress levels. Brilliant. But there is a risk that you think, oh, gee, yeah, man, I had a 30 minutes, I've just done 30 hours or whatever it might be. There's a really nice paper, or a set of papers, and essentially work done by George Slavich and Steve Cole, they're at UCLA. And myself and Julian Able, who's a retired palliative care physician, we recently curated and edited a set of scientific papers on the importance of community and social connection and health. And one paper was written by Steve Cole and George Slavich, and they talk about social stress and the effect that has on our physiology. And one thing that was particularly impactful to me was reading it, and you kind of, they talk about social rank, perceived social rank, right? How we see ourselves compared to others. And as you sort of like read, you know, I'm reading what they've written, I'm like, this is why social media is so bad for our health, because what happens is that you spend all your time seeing people who are doing more than you, more successfully, richer than you, better than you, looking than you, whatever, like however you perceive that compared to yourself. And what we do is then we rank ourselves, like where are we in the world? And we demote ourselves internally because we see all these people who we think are better than us, or doing more than us. And being demoted in your perceived social rank creates a social stress. And so it creates a physiological response similar to when we're socially isolated. And we know that when we're socially isolated, we see shifts in our physiology. It changes our immune function. It changes baseline levels of inflammation. This is a evolutionarily conserved response, right? So if you're isolated, then your immune system shifts away from being better at dealing with things like viruses, respiratory viruses, because you're not surrounded by anybody to give you a cold or a flu. And it shifts more towards an acute response that makes you better with wound healing, for example, which is survival, that's important, right? There's nobody to look after you if you get injured. And these things, you know, we can measure them in our physiology. However, that comes with a baseline lower level of inflammation because your body is like ready to respond to an injury. If you continue that long term, you then see an increased risk of many chronic diseases, heart disease, dementia, because of this immune system shift. And that is driven by social isolation, but it's also driven by other social stresses such as a lower perceived disease. Social rank. Yeah. I remember reading that in that. I think it was in the ADAPT chapter in the book, which is one of my favorite chapters. That whole idea that the immune system shifts, I think is really interesting. So I just want to clarify something because I think, I don't know if you said lower inflammation or higher inflammation. When it shifts because you're lonely, the cost of that is a higher background level of inflammation. So it makes us inflamed basically being lonely. Yeah, exactly. Yeah. And some of that being a perception is quite interesting. I once had a very successful author on the podcast, Will Stor. He's written some brilliant books. We chat about status. And I remember chatting to Will and it came up this idea that Will is more successful than most authors in the whole scheme of things. But he's not as successful as some. And let me define success in terms of book sales. There's many ways to define success. And so Will was, you know, quite honestly just saying, yeah, but all I see is all the authors who are selling more than me. And they're doing better than me. And it just shows that it doesn't matter who you are, no matter how successful you perceive yourself to be. I agree with you. I think that may be one of the darkest things that happens to our subconscious when we're spending a lot of time on social media. Because this is one thing I thought about a few years ago. We can talk about this stuff, right? People can know it and go, yeah, when I'm on social media, don't take it seriously. It's just that highlights real, right? I don't think it matters. I think your subconscious is constantly being fed that you're not enough. That everyone else is doing better than you. And I know in my own life, so I've recently taken all my social media apps off my phone. So I can go on them on my laptop, but I can't easily get onto them on my phone. And I just feel better. Like that's subjective. I can't give you a try for that. I just, I just feel better. There are, well, there are actually trials that do look at that. Today's episode is sponsored by AG1, a daily health drink that has been in my own life for over seven years. Now, this is the time of year when our immune systems are under the most pressure. Between spending more time indoors, travel and seasonal bugs, it's natural to look for extra ways to support our immune defenses. But most people don't want to juggle multiple pills. They want something simple, effective and easy to stick with. AG1 is a daily health drink that provides key immunity supporting nutrients, vitamin C, vitamin A, zinc and selenium, all of which contribute to the normal function of the immune system. These nutrients are included in highly bioavailable forms, meaning they are much easier for the body to absorb and use. 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Now, one of my favorites is their Demi red light therapy device. I absolutely love it and personally have this device on when doing my morning meditation. And I also tend to read in front of it in the evening before I go to bed. And I've noticed some quite significant changes, improved relaxation, enhanced focus and deeper sleep. And there are so many studies now showing the potential wide-ranging benefits of red light therapy, including better eye health, pain relief, reduced inflammation, enhanced recovery, improved sleep and even better skin. So if you're looking to take charge of your health at home, I highly recommend you consider adding the Demi red light therapy device into your daily routine. And Bonn Charge are giving my audience 20% off all of their products on their website. Just go to bonncharge.com forward slash live more and use coupon codes live more to save 20%. There are actually trials that do look at that. It's interesting because the timeline matters. If you ask somebody how they feel about quitting social media after just a week or two, they might not feel that good about it. You still get FOMO and these other things because you're not interacting in that world. It's like asking how a smoker feels two days after they quit. They don't feel great. But if you go out long enough, four weeks plus, there seems to be an overall increase in well-being. And this is also driven by what people do instead. This is where a lot of the issue with social media comes from, I think, because it can be a way to increase social connection and social context. You wouldn't have had otherwise. And we see this in studies in older adults where they're using Facebook for the first time. They can communicate with family members that they wouldn't have done otherwise, share photos, that kind of stuff. That is a net benefit. But if you're using social media to consume content instead of going and meeting people in real life, that's a net negative. And we see that very clearly in terms of well-being. So yes, there is maybe some benefit from at least decreasing our exposure to social media. But you can also curate the way that you use it such that it becomes a net positive. Plus, you need to think about what am I doing instead? And then there are multiple different ways to navigate that. But just appreciating that these are potential issues based on the fact that if you're constantly being exposed to content from people that makes you feel less than either consciously or unconsciously, it might be having a net negative effect on your health. Yeah. It's the tool, right? And all like all tools, it depends how you use it. I agree. And at the same time, I think something has happened recently, which makes that even harder. So a few years ago, I thought, right, I'm going to cull everyone when it was still called Twitter. I thought I'm going to unfollow everyone and just follow the people who I think really are giving me value. Right? So some of these, you know, there's a few endurance coaches who I really like following. A lot of they share research papers on exercise physiology and their experience. You know, the things that I really enjoy looking at. Yeah. And I did that for a while. It worked. Okay. Because whenever I go on, all I'm seeing is stuff from people actually I want to see stuff from. But I think algorithms have changed. I where you don't only see stuff anymore from people you follow. Yeah. In fact, that's only a very small percentage of who you see. So I do think it's getting harder. And you do talk about this in the book, right? You talk about the healthy and days of social media. And I, you know, you were very early because I think your uni was like the third uni to get Facebook or something like that. Yeah. One of the first you needs to get Facebook outside of the US in 2004, I think we got it. Yeah. But I remember back sort of, I don't know, 2007, 2008, Facebook was great. Yeah. You'd, it was wasting in touch with mates, you know, you'd share photos, you'd see what your mates are doing. You might follow a few people and see their content. And it was, I think, unless I'm looking at it through rose tints and glasses, it seemed to be connection, like social connection. Yeah. I think for many reasons, which you don't necessarily have to go into on this show today, but you're right about, is it prime? Prime. Yeah. But just explain what prime is. Yeah. So this is information that we prioritize as humans. So the prime stands for prestigious, in group, moral and emotional. And this is because we prioritize information that tells us something about our social environment because that's going to help us survive. Right. And we are inherently social beings. And so this then is what's, I think, leveraged by the algorithms to have us stay engaged or, you know, continue scrolling. And so they know that information that you will respond to, either positively or negatively, in a large way, is the kind of information that's going to keep you, keep you hooked in. Because your brain thinks, this is important information about my social environment that I need to gather such that I will then survive better in my environment. And so that will include the things that you want to see. Right. But it might also include stuff that they know will elicit a negative emotional reaction because you get these large swings in dopamine that then drive learning, right? That dopamine is largely responsible for learning what's important. And that's done on purpose. And so I think that social media takes advantage of our need for social information whilst giving us social disconnection. But we keep going back because we're like, well, next time I'll learn something that will really help me. And that's how you get sort of stuck in the loop. Okay. Tommy, so so far we're basically up to the point where we're saying that a lot of dementia cases are preventable, which is very empowering message. You've mentioned that the brain can adapt at any age. Again, very empowering. It doesn't matter how old you are when you listen to this. I don't know if we'll get to your owl story or not today, but you start the book with a beautiful story about owls, which really highlights this point, right? That the brain can adapt at any age. We're talking a lot about social connection. And I want to really talk about the 3S model that you put forward in the stimulated minds. Okay. Because, well, firstly, I do have to say, I think that's one of the best health reports I've ever read. Thank you. It's absolutely fantastic. And it's so thorough. It's what I'll tell you what I like about it the most, not only is it grounded in a lot of scientific research. It's very clear that you've got a lot of practical knowledge about the application of it as well. And that's not always the case. There are sometimes books from researchers which are great and you see all the science. But as someone who spent many years practicing, I'm like, yeah, but that doesn't... There is a different skill, I think, to application of these things for real life people who are busy. So it's a beautiful blend of that. And also, and I know this one, I've already taught you, you seem to know a study for absolutely everything. I can just say anything. And you know a lot of studies, don't you? Yeah, that's part of... It's an occupational hazard at this point. I think the book has a reference list of... It will be about 2,000 studies. 99.9% of which are in humans that people can have access to if they're in digging in further. It's very rigorous, which I think is great. But I really love this 3S model that you put forward in the final third of the book, as it were. Stimulate supply and supports. And just before you sort of go out line it for us, something I read last night, which I've been thinking about ever since, is this idea that nutrition, of course, is important. But I think it's only one of the assets. Yeah. And I think that's quite novel because we think, well, what can I eat to support my brain? You're making this case throughout the book that actually stimulus to the brain is perhaps the most important thing. So it made me think, well, hold on a minute. If you think about physical health, right? We can talk about eating protein for your muscles. But if you're never stimulating your muscles with movement or with lifting weights, is that protein really going to translate to muscle growth? And then I thought about it through the lens of the brain. We can have the right diet, the right omega-3s and all the things you talk about, right? We can have them in our diets, but that seems to be only one of the assets. If we're not also stimulating our brain, we're perhaps not getting the full benefit. So I said a lot there. I think it's interesting. Can you walk us through the model? Then comment on anything I've just said that you feel is important. Yes. So what you say is exactly right. And where the model comes from is all the different pockets of neuroscience that I've worked in or coached in over the years. So I'm thinking about the developing brain, thinking about individuals who suffer some kind of brain injury during life, like a traumatic brain injury or concussion, or trying to help elite athletes perform at their absolute best. And then also thinking about what are the factors that contribute to long-term cognitive decline and dementia. And you see the same things pop up again and again and again, which sort of makes me feel like there are these core foundational inputs that the brain requires both on a day-to-day basis, but then also long-term. So things that you can do right now to improve how your brain functions today or tomorrow, then translate into a longer term, lower likelihood of dementia, and you're much more likely to maintain the function that you do have, or maybe even improve it in your 60s, 70s, 80s and beyond. There are a whole host of factors that we can talk about. We've already talked about several of them. But for me, they coalesce around these three common areas, which are the three S's. So stimulus, supply and support, like you said. And I think that stimulus is something that we inherently know is important. Everybody said use it or lose it at some point. But I don't think we've quite understood what that truly means in order to give our brains the stimulus or the stimuli that they benefit from the most. But I do relate it to this idea of physical performance and physical health because we kind of inherently understand that. If I want to get bigger and stronger, I want bigger biceps, the most important thing to do is to do bicep curls. I can improve my response to my training with a higher quality diet and making sure I attend to sleep and recovery. But I can't just drink protein shakes and nap and hope that my biceps get bigger. Okay. This is great. So in that physical health example, right, you're making the case that the three S's are still important, but the stimulus is the most important, which I think makes intuitive sense if we step back and think about it. Exactly. And in reality, the function of any part of your body is driven by how you use it. Right. And you can think about your bones when you do your weightlifting, or you can think about your heart when you go running. The way that we use our body is the primary determinant of how it functions. And the brain is exactly the same. So I'm making the case that how you use your brain is the primary driver of how it works. Okay. So we have this three S model and I wonder if we could just go through the three of them and stimulate. How do we stimulate? Yeah. Supply. How do we supply? Support. How do we support? Yeah. Yeah. Give us a sort of top line on that. Sure. So the stimulus that I think that we need more of, and I will acknowledge that I quite like the title of the book, The Stimulated Mind, because it's provocative in a way, because right now we are at the same time under stimulated and overstimulated. Yeah. Everybody feels overstimulated, right? Tommy, how can you tell me that my brain isn't stimulated enough? Like I'm constantly feeling stimulated. And so it's the type of stimulus that really matters. And I think we can talk about, and you know, social media is one of those things, we can talk about how you can decrease these other stimuli that make us feel overstimulated or stressed, because that's an important part of it that will end up in our support bucket. But the kind of stimuli that drive the development of the human brain are learning, knowledge acquisition, skill acquisition, social interaction, pro-social behavior, languages, music, complex movements in sports, social connection, these things that require us to learn a skill and apply that skill in a way that involves processing information quickly, in a way that involves responding to the environment, responding to other people. And through multiple senses, right, our hearing and vision and touch, taste, smell, all of these things actually can be important stimuli for maintaining cognitive function. And it's that kind of complex skill development and expression across all those domains, including arts, including computer games, like complex computer games can even improve cognitive function, because it's the same thing, you know, multi-sensory, complex cognitive stimulus. These are the things that I think we need more of, and we need to spend time really attending to them and focusing on them. Is it the complexity of the stimulation? You mentioned this kind of the paradox of the time in which we live, you know, the book is called the stimulator in mind, as you say many of us go, but most people are overstimulated, but is it that it's almost like we've got too much of the wrong kind of stimulation, like the unidimensional, perhaps, like the scrolling, because, you know, let's say you wake up and you go onto your social media platform of choice for an hour whilst drinking coffee, okay? You're getting stimulation, right? You might in that hour see more information in the hour than maybe your ancestors would see in a year, or maybe even longer, right? Okay, let's just work this through. Let's say for that one hour, you got all of this stimulus in, right? And then we go to the supply and go, yeah, and let's say you've got an exceptional diet, and you're moving your body regularly, so you're getting supply, and you're sleeping well that night to allow that learning. In theory, could that stimulation be beneficial for the brain? To an extent. So if you're using Instagram and you're consuming educational content, such as your learning important facts. And thinking. And thinking. Absolutely. That can be an important stimulus. And we know that educational attainment is the primary driver of, well, so like education and the environment are the primary drivers of brain development. And educational attainment is one of the best predictors of long-term cognitive function and cognitive decline. So that's literally just every day your job is learning, right? You're learning and you're applying that knowledge. That's why attainment is important, right? Actually remembering things, applying that knowledge in exams or however that knowledge is tested. Okay, so attainment that's in it. So it's not just going to school and passively consuming stuff. You have to actively engage in some way. Yeah. So to kind of like really simplify that, it's the difference between, you spend 10 years at school and you pass your A-levels, or you spend another few years and you get an undergraduate degree, right? Those levels of attainment versus you spend 10 years retaking the same year in school because you never pass an exam, right? Right. You spend the same time in education, but those are two very different outcomes in terms of applying your brain and making sure that you're using the knowledge that you've gained. And can the stimulation that we need, like the primary stimulus to the brain, we don't all need the same because when you've been on the podcast, you have spoken a lot about, you know, when do we have peak cognitive status? Is it after university or in your late 20s maybe in kind of the modern Western world in terms of how people who go through education and then they might go and study beyond that. But then it made me think about hunter-gatherer communities. And I thought, well, do we know in these traditional societies whether they have high rates of cognitive decline if they've not done the same type of education? But then I think, well, but they would be getting stimulated in other ways, maybe not in the conventional or the modern academic stimulus. You know, the stimulus can come in a variety of different forms, can't it? Yeah. I think that's an important clarification to make because these studies are done in a typical Western environment. We're doing specific tests of cognitive function, you know, related to a whole bunch of different functions of the brain that could involve memory, attention, decision-making, processing speed, like how quickly you can process information. But these are just the data that we have access to. This is how we understand it, right? And what those data show is that the cognitive function peaks around the time that you leave formal education. So the later you leave education, the longer you spend at school or you're getting degrees, the higher and later your peak of cognitive function. Because I think you're just getting the stimulus on a day-to-day basis. But that doesn't mean that that's the way that you have to do it, right? This could happen outside of a formal educational setting. You know, in those traditional hunter-gatherer groups, they will actually constantly be learning. And then at some point, they'll transition from learning to teaching, right? This is a big part of, you know, later life, where we know that older adults in those communities in their 60s, 70s and 80s are just as active as their younger community members. But they transition to being repositories of knowledge. And that's the expression of these complex skills and information that they've learned back to younger individuals who are now developing. So they're still constantly engaging their brains, it's just then using the information that they've gathered. So cognitive stimulus of this type can come from anywhere. And you see very interesting studies looking at different types of skills that have the same core effects on the function of the brain. So there was this, one of my favorite papers of all time was published very recently. It was called Creative Experiences and Brain Clox. And what they did is they looked across multiple creative experiences or skills. So they had tango dancers, they had musicians, they had visual artists like painters. And they actually also included a computer game group, gamers, including a randomized controlled trial where they had people game and looked at the effect on their brains. And across all those different, these are very different skill types. But across all of them, they had this, as you gained expertise in these complex skills, they saw the same effects on different networks and functions within the brain. So the brain has all these different regions, and each region has a specific function. But what we're now learning is that really functions are distributed across the entire brain into these complex networks. And how well these networks are connected and how efficient they are is a primary determinant of how our brains function as we get older. So as we get older, these networks tend to become a little fuzzier and a little less efficient. And that makes it harder to say, pay attention or maybe slightly harder to remember something. But as people gained expertise in a complex skill, those networks strengthened, regardless of what that skill was. This is networks like the front of prior to networks, really important for attention and memory. So what that says to me is that when we're doing these inherently human, creative, multi-sensory things, that requires us to pay attention, it requires us to focus, it requires us, you know, it drives neuroplasticity through learning. And then this is what's important for maintaining brain function, the function of these networks for processing information and language and the social aspects of the things we want to do with our brains. And that also then means, depending on what you find interesting to do, I just listed four or five things that are very different, but they all have similar effects on the brain. So that just means, pick the one that you enjoy and start by not being good at it and get better. And it's in the getting better, it's in the learning and the failing. That's what drives the improvement of connections in the brain. That's what drives the improvement in the function of these networks that then ultimately translates to improve cognitive function over long periods of time. That whole interconnected nature of the brain, but also more widely the body, is also another theme that underpins the whole book, which I absolutely love. It's how I've always seen health and well-being. And I think when people think about, I guess, the typical, you know, in a vertical, it's lifestyle factors like nutrition, exercise, sleep, stress management, whatever it might be. I love that section at the end when, and you, you know, you quote quite a few people there about the interconnected nature of health. You change one thing, you change everything. And I think that's really empowering for people, especially when they get bogged down with, well, that expert said, these are the benefits of yoga. And that expert said that, you know, this is the benefit of running. And that expert said, these are the benefits of meditation. And yes, yes, yes. And you don't have to do them all. You do the stuff that you want to, and you'll probably find that that starts to change other things in the body. Yeah. So that's, and I think to fully unpack that, we can like flesh out the model a bit more, because then you kind of understand how this works, which then gives us a lot more agency. And it's a lot simpler in terms to start applying this stuff and benefiting from it. So we have stimulus, right? You stimulate your brain doing something, right? Starting to learn a new language. When the areas of the brain that are related to that skill that you're learning are activated, they ask for more blood flow. There's this thing called neurovascular coupling, where the neurons and the astrocytes in that area stimulate the local blood vessels to bring in. They need more oxygen, right? They need more glucose or whatever fuel you're fueling your brain with. And so those blood vessels dilate, you know, they widen, they bring in more blood flow. This is then, so now we're in our supply bucket. And so that's where like cardiovascular health becomes important. We know that things like high blood pressure, high blood sugar are important risk factors for long-term dementia. And that's at least partly because they affect the health of those blood vessels. If you want your brain to be able to react and adapt and do a whole range of different things, that our blood vessels need to be healthy and respond accordingly. So you've stimulated your brain and now we're going to the second S supply. When you have chronically high blood sugar or you have poor metabolic health, you are negatively affecting the supply. And the supply is important to get the most out of the stimulation that you just gave your brain. Exactly. And is this why perhaps we read things where let's say we've done a 90-minute bounce of work? And, you know, because my son's in his GCSE, I'm talking a lot to him about how he revises and how important it is to move his body. And, you know, so, you know, you do the stimulus, let's say you've rev- whatever, whether it's a child or an adult, you've let's say you work for 60 minutes on something quite cognitively challenging. Is it overly simplistic to say that if you then go for a walk or a run, you've done the stimulation with a one-hour work, the run and the walk has basically got your blood flowing. So your, you know, your supply from nutrients, from oxygen, everything is increased. That's correct, right? Yeah. So one of the reasons why movement is so beneficial for the brain in the very short term is because it improves blood flow to the brain. So the supply, the second S. It improves supply, exactly. And then that also translates long term, right? Long term, the more, you know, if you're more physically active, you may maintain better physical fitness and physical health, metabolic health. Then you maintain good blood flow to the brain because your blood vessels are healthier. The other part of that is that, and we may get to this more later, is that you increase, if you increase arousal, which exercise does, you increase some of the neurotransmitters that are related to learning and focus and attention. And that then afterwards, once you've taken a chance to recover and adapt, you remember things better. So we know that if you do exercise before or after learning something, partly due to blood flow, partly due to arousal and neurotransmitter release, you will then remember those things better. So that's why movement around learning can be really important. Plus, if you've been learning because you've been, you've been sat in a chair the whole time, we know that if you sit very still for long periods of time, blood flow to the brain starts to decrease and that can decrease mood and attention a little bit. So it's another way to just kind of reactivate everything related to that learning process. OK, so let's get back to the three assets. We've stimulated the brain and now you're talking about supply. Today's episode is sponsored by Peloton. Now, we all know that moving our bodies more is good for us. But despite that knowledge, many of us find it hard to actually implement. And that's where the new Peloton Cross Training Bike Plus, powered by Peloton IQ, can really help. It's built for fitness breakthroughs with real-time insights and endless ways to move. And you can go from cycling on the bike plus to strength training off it with one smooth spin of the swivel screen, which offers endless ways to train for a well-rounded routine. While you lift, Peloton IQ counts reps, corrects your form, and suggests new weights. So you're always making progress towards your goals. And Peloton's movement tracking camera provides real-time feedback so that you can train safer, lift smarter, and make every move count more. With over 15 types of workouts, expert instructors to keep you motivated, and a personalized plan tailored to your goals. The Cross Training Bike Plus takes the guesswork out of working out so that you can move freely and let Peloton handle the rest. Let yourself ride, lift, stretch, move, and go. Explore the new Peloton Cross Training Bike Plus at 1peloton.co.uk. That's O-N-E-P-E-L-O-T-O-N.co.uk. And please note Peloton All Access Membership is required to access all Peloton content and applicable features on your Peloton hardware. So you've stimulated an area of the brain or the networks in the brain. We're now bringing in more blood flow. So we've talked about why physical health becomes really important there to maintain healthy blood vessels, maintain good glucose supply to the brain, and we know that in individuals without Simon's disease, in particular, there's a decrease in glucose getting into the brain. There's two parts to that. One may be due to decreased stimulus. If you're not using your brain in the same way, the brain is going to ask for less glucose, but there may be also an issue with the glucose getting in if we have poor physical health, metabolic health. So then the final part of supply is nutrients. The critical nutrients that we know are important, both for cognitive function on a day-to-day basis, but also in terms of long-term dementia risk. So the ones that we have the best evidence for, vitamin D, iron, mega-3 fatty acids, B vitamins, especially the B vitamins related to methylation, like B12, folate, B6, and riboflavin, other things that we see are important for a long-term cognitive function are the antioxidant vitamins like vitamin C and vitamin E. Antioxidant polyphenols are very cool things that you can get from, you know, that make berries purple and red, or that make fruits and veggies orange and red, so like gluten, zeaxanthin, astaxanthin, that's what makes shrimp and salmon pink. These antioxidant polyphenols seem to have really interesting benefits for the brain, both in the short term and the long term. And then some other minerals like magnesium and zinc, things like that, become important too. So those are the critical nutrients that we're hopefully getting from the diet that then get directed to the parts of the brain that are building new connections, building new synapses, as it sort of cements the things that you're learning, right? And so that's the final part of supply. And then you've stimulated a part of the brain, you've brought in all the resources it needs to do the thing that you've asked it to do. Then we know that for a tissue, including the brain, to adapt to a stimulus, it needs a period of time to do that. And that's usually during rest, right? So it's the same if we're going training for something like a marathon, right? You don't get faster while you're running, you get faster while you recover after the training run that you did. And so the brain is the same. This is where sleep is really critical. So now we're in the support, the third S. So sleep is a big part of support. That's when all those connections that we've made are cemented. That's when we're building that function in the brain based on the stimulus that we've applied. But we can also further support that adaptation through a variety of different things. So that's where hormonal status can become important. That's where other factors that get released by the body can support the neuroplasticity and development in the brain. Things like brain-derived neurotrophic factor, which are released during exercise. These can help to support the direction and creation of new connections in the brain. And then the other side of support is we want to avoid things that inhibit that process. So smoking, excessive alcohol, air pollution, other things that can cause chronic increases in inflammation. So we already talked about the social side, but that could include like dental health and oral health is an increasingly recognized risk factor for dementia because either because of the direct effect of the bacteria, but also maybe the inflammation that they create. And then chronic stress plays a role here too, because we know that if you never get a chance to fully switch off because you're chronically stressed, then that is sort of like an impair ability to adapt. So then you realize that all these different buckets are interconnected, right? So stimulus drives supply and stimulus also drives support. So when somebody does a cognitively challenging task, they then have a greater need for sleep that evening. So they actually think they may sleep better because they have a greater drive for it. So just sorry to pause you there, but that could mean if someone's listening to this and they sometimes struggle to sleep and there's many reasons for that, one of the reasons might be that you're not stimulating your brain enough. Yes. So one of the ways that we know that one of the ways we understand that the best is through exercise, we know that exercise improves sleep, can improve sleep onset as well as sleep quality. But there are really interesting studies in older adults where they have them do a brain training program for a few weeks. And what they see is that compared to a control group who are just doing much less cognitively stimulating stuff on a computer, they were using like paint to just like make some things, but it's not the same as like really challenging your cognitive function with some of these brain training programs. Those who are cognitively stimulated, they ended up sleeping better because they're creating greater sleep drive. And so I often wonder if part of the reason why as we get older, we sleep less is because we're not using our brains in the same way. We're not stimulating them. We're not asking as much of them. So we're not creating that pressure, that sleep pressure, that drive to sleep. And so because all these things are connected, that then means exactly what you said earlier, which is when you change one thing, you change everything. So we know that if you start to sleep a bit better, then your blood pressure improves and your blood sugar improves. And the next day you feel more sociable. So you're more likely to engage with other people in some kind of social interaction. We also know that if you're less fatigued because you've slept better, you're more likely to engage in a cognitively stimulating task because we avoid cognitively challenging things when we're tired. And the same is true if you stop smoking, blood pressure improves, inflammation improves, you're more likely to exercise. You're more likely to make a more like nourishing meal choice. If you start to exercise, then you sleep better and all those other things kind of come off that. So if we understand that these are not a long list of things, all these things we have to do, but instead even just within one bucket, you would identify something where you're like, oh yeah, I could start to make a small change there. We know that benefits tend to be linear, right? A little bit more is going to have some benefit, right? You don't have to do four hours of exercise in order to see benefit, right? Anything is going to start to be beneficial. But you pick the thing that you feel like you can make some change in. You would enjoy doing or you're able to do. The whole network starts to shift in your favor. And then you can start to come in from other places as well. But understand that it's not a long to do list that's overwhelming. It's a network that allows you to come in pretty much anywhere and start to see big benefits. That has huge practical application. I think back to early on in my career. And I very quickly learned that if I was to tell a patient or give them loads of things that they could do, you know, say, hey, I don't give them the research, say, hey, you know what, if you do this, it's going to do that. If you do that, it's going to do that. And they come back four weeks later, they haven't done anything. Yeah. Right? I was like, oh, I've actually just overwhelmed them. Have you found that to be true yourself in your own sort of coaching and in your own life? Absolutely. I think that right now it's very common on social media to see here's a list of things to do for your brain health. And they can all be very evidence based. It could be all the things we've talked about today. But I've seen time and time again, you give somebody a list of 37 things, they will do zero things, right? For those exact reasons. And my favourite personal experience is the first time I worked in Formula One. I had sort of interacted with the team a little bit before. I do all of my Formula One work through a company called HINSA Performance. And I was invited to go to the US Grand Prix in Austin and I was going to be in the paddock, you know, meeting with coaches and drivers and team principals and all these amazing people. And I was a big Formula One fan. So this was like a big deal for me. You nervous? I'm very nervous. And then I did what any good nerd would do and I'm massively over prepared. I was like, I went in armed with a hundred things and 200 studies. We're like, I'm ready. I've got all these things that people could do to improve performance and health and all this kind of stuff. And I remember having a conversation with a coach. And so the way that HINSA works is the majority of the drivers that we work with, they have a HINSA coach. This is usually somebody they have like a master's degree in strength and conditioning or they're a physio or some of them have a psychology background just depending on what the driver needs. But they're there like inserted into the life and well of the driver. They're there every day. They hold the helmet next to the car, hold the umbrella. They're doing all the warm up drills. They're doing all the training and you're looking after diet, all this kind of stuff. They're sort of like organizing their lives. And these are these are the individuals that I spend most of my time interfacing with. Like how can I help the coach do their job better? And so I'm meeting with this coach for the first time and I think I probably start throwing out all these different ideas. And he's like, we've got time for maybe one thing, maybe, right? What you don't realize or maybe you don't think about is that first of all, you know, drivers are essentially jet lagged nine months of the year because they're constantly flying from place to place. Plus you have to do all the races, but then there's all the preparation in between. There's media days that you've got to go and schmooze the sponsors, right? Because everybody wants their piece. Plus you've got a million people like me showing up and be like, hey, try this thing, do this thing. Hey, right? And so then it comes, he's like, we've got time for one thing. What's the one thing that you think would have the biggest impact? And so like ever since then, that's the mindset that I've had to take in. Like if we, we can start with a big net, but first of all, like where's the biggest potential anchor or issue that's affecting this one individual? What's the highest return thing that that person could do with the time and resources and things that they have available? And that's where you start. And yes, sometimes you get it wrong. And that's true for all of us, right? You need to experiment. And like, of course, like some of this requires some trial and error. But starting with the one thing that you think is most likely to have an effect is always going to be much more likely to actually start to move the needle because you'll actually start to do it. Rather than thinking about a hundred things that I've suddenly thrown at you. Like, well, I just don't know where to start. So I won't do any of it. Yeah. You mentioned four-way one. And I know we've, I've always wanted to delve deep with you about your experience. It's super fascinating. As you were describing, the drivers there and the pressures on them, the pressures to compete, to perform at high level, to deal with jet lags, sponsors, everyone wanting a piece of their time. I thought, wow, that must be quite stressful. And perhaps some of these extra commitments that they have potentially are going to get in the way of their ability to perform, which is ultimately what they're paid to do. But of course, they have to appease their sponsors and all that kind of stuff as well. From all your time in Formy the One and having worked with several drivers, would you say there is something that's common to all of them? Like an, a skill or an attribute that actually, you know what, they all seem to have that. Something that I see across, you know, all the successful athletes I've either worked with or interacted with is in a way that's relevant to them, focusing on process above results. Because, and I think this is, this is also relevant to everybody. Yeah, for sure. Because you will never achieve the result or, and you can never guarantee the result. Right. But you can enjoy the process and figure out what works best for me, how can I make this better? How can I continue engaging with that? How can I be more targeted in the things that I do and don't do so that I have better overall balance? I think it's people who, who love that process and really focus on improving the process itself then end up consistently achieving high levels of anything. And this is, this works in academia and sports and, you know, any kind of area that you might think about. The other thing that I see very consistently, and I don't just say I like we as a team, the team that I am part of, I'm head scientist and motorsport for HINSA. But, you know, we have doctors, we have coaches, we have a bunch of performance experts, psychologists, right? And we all work together. The thing that I see most consistently then is, is this need for down regulation and recovery? Right. So if we're thinking about our three S's, it's very unlikely that we can come in and somebody's already, you know, performing at that level and say, do you know what? You need more stimulus, right? Right. Right. Because they've spent their entire lives learning how to drive those cars and dedicated to that craft. They, right, you're driving around the track at 200 miles an hour. You get, you're getting plenty of stimulus, right? And, you know, we spend a lot of, we spend a lot of time, you know, looking at blood work, looking at diets, you're tweaking those things just to kind of make sure that they have all the bases in place. But really recovery is where a lot of, a lot of the benefit is going to be seen. Like how can we get, allow these guys to rest, recover, down regulate, adapt so that they can get the benefits from the stimuli they're receiving, the physical, in their training, you know, in the car, you know, everything they have to do around engineering and working with the teams there. So, so the third S support. The third S becomes really critical for them. And that's probably where we spend a lot of our time focusing because in driver development, and this is something we do a lot of now as a company and we're doing more and more over time and trying to improve these processes. You know, if you have a young driver wants to be in Formula One in five, 10 years time, yes, we might focus on stimulus. How can we build skills and fitness and performance, cognitive, physical? And so that's maybe where we focus. But once you get up to that tip, it's thinking about how can we make sure they're getting the most out of what they're doing and, you know, so that they can sustain performance for long periods of time. Yeah. It reminds me a little bit of, I think a case you write about in your book when you first started coaching, perhaps, was there a, was there a runner who was, oh, you can tell the story. Because it's, it really now I'm looking at that fresh through the lens of the three Ss going, you can stimulate all you want, a supply or you want. But if you ain't got the capacity for the support, for the rest, the sleep for you to absorb the stress and adapt to it, you ain't going to get any faster. Yeah. And so this is, this is something that's very common in amateur athletes. So like this, this individual was, they were, they were a high performer. They can, they competed at a high level, but they were, they were an amateur as in, you know, they weren't paid to take part in their sport. And so this was a runner who came to us several years ago and did, felt like his performance was going backwards. So like he wasn't getting the race times that he wanted and was also sort of like slipping back in the field whenever you compare, compare to others. But he was training, wasn't he? He was training. Yeah. He, and was training very, very hard. Plus you layer on top of that, the travel schedule that was, that was quite brutal because every two or three months he would travel internationally to compete. And so the reason why I tell this story in the book is because it was the first time that I, you know, as a coach previously, I would focus on stimulus, right? What's the training program? Like how can we improve that? But it was the first time when I looked back, I looked across everything that I had from this individual and thought, all these other pieces are the most important pieces. And so like I think the first thing I said to him was, if you continue this, the only thing I can guarantee is that you'll get a divorce. Right? And it was a bit tongue in cheek, but basically you're seeing somebody who's over-trained, not eating enough, not able to eat enough calories to, to, or not able to have the, the cognitive back. The cognitive bandwidth to focus on getting enough calories in because they're so focused on their training, plus a brutal travel schedule, plus, right? There are, there are husbands, there are father, right? They have a family to, to, they should spend time with that they're not, they're not focusing on because that's just like so focused in on, on their training. And this then essentially made me realize that it's all these, all these other things are going to affect our capacity to A, get the benefit of the stimulus that we're applying. But, you know, B, like the overall picture of, of what it even means to be an athlete or be an individual in the world that, that we want to be, right? He presumably, and I think this was the case and, you know, he, he made changes to his training program and his, and his, his race schedule to kind of take, take account for these things. Right? Having a family and being a husband and father was more important than racing. But like once you're so deep into this and you're, you know, so stressed and overworked, you become very focused on singular things. Like what's the thing that I can control? And what he felt he could control was like, I'll just train more. I'll just do more. Right? That's the thing that I, I, I, that's the needle I can move when actually that was the thing you needed to pull back on so that he could then benefit from that. And actually think about who is actually, who is the person, who, who is the person I want to be that? Yes, is an athlete and performs well, but also does all these other things. And so then by focusing on the recovery aspects, by focusing on these other areas, maybe even training a little bit less, making sure that he was eating enough, right? Enough supplies kind of support this, the adaptation. Then he ended up doing less, but performing better because he was taking care of these other areas. I imagine a lot of people listening are probably thinking, well, yeah, I could probably get more stimulation. You know, I could probably learn new things or get more social connection or whatever it might be, learn new skills, all that kind of stuff. Regular listeners to this podcast will of course know about the importance of regular movement, good nutrition, but the stuff that you'd put in that second bucket of supply. But I think the third S of support is something that a lot of people need help with these days. So many people struggle to downregulate and switch off and maybe they're not getting the right kind of stimulation in the day or when they're scrolling in the evening. But it is so common now for people to feel wired but tired, right? They are knackered, but they can't switch off and fall asleep. So I know you sort of, there's a whole chapter on this in the book, but have you got some sort of practical guidance for people who might be experiencing that at the moment? I think one of the things that ends up being very common is because of the way we structure our work day, we get to the end of the work day and we're still sort of stressed about what we have and haven't done. Plus, we're sort of desperate for some kind of way to switch off that we end up spending a lot of time on screens, social media, right? And those things can be beneficial if we, or they don't have to be detrimental if we craft our experience with them. But a lot of what happens when people can't sleep, this sort of tired and wired thing, I think is downstream of our lack of structuring how we spend our days. So in, one of the first people that I met when I was working, when I started working with Hintzer, there's a guy called James Hewitt. He used to be a professional cyclist and now he's sort of a cognitive performance specialist. And he wrote a book with Aki Hintzer who founded Hintzer called Exponential, where they outline this idea of cognitive gears. And it sort of again relates to the physical side and physical training. But basically, we have three gears in which we can use our brains. High gear is sort of really deep focused work. Like this is when we're paying attention to one thing at a time. We're doing something complex. We're learning. We're problem solving. You know, these big tasks that we have to get done in our days. Low gear at the other end is, you know, when we're fully switched off, relaxed, you know, our brains free associate, right? You know, this is why we have moments of inspiration in the shower, because we're not sort of constantly having to deal with other inputs. Or this is, you know, often happens when I'm in the gym. Like that's when I'm not thinking about anything else. It's like ideas kind of appear. Same when you go for a walk, right? And ideally, your brain spends a lot of time in this kind of mode, because you need that mode to recover from this like complex cognitive work that you've been doing. Even during the day, like in addition to sleep, where we spend most of our time, if not all of our time is in the middle gear. So think about high gear is like sprinting. Low gear is like walking and middle gear is kind of like jogging or running. And we basically spent our entire day running. And if you imagine, like how exhausting is it to run all day? You couldn't do it, right? But you just like keep trying to keep keep going. And this is essentially what we're doing to our brains in the modern work environment. And it's the middle gear is meetings, emails, dealing with Slack and teams, and all these different inputs, multitasking or task switching across multiple, like trying to deal with multiple things at the same time. So like you're trying to do some work and then an email comes in or a message comes in. Or we get to the point where we're so used to distractions that we distract ourselves. There's some really nice work from Gloria Mark, fantastic book called Attention Span, if any of you's interested in this. But basically, if we're distracted a lot, our brains get used to distractions. And then we go looking for distractions. You know, like when you go to pick up your phone, even though it hasn't gone off, I mean, you have your framework like, why now? Why am I doing this? Like what was it for? But we basically get to the point where our brain gets used to distraction and goes looking for it. And so we know that when we're forced to multitask or we're interrupted in our work, which is essentially everything we're doing in the modern work environment, it's inherently stressful. It creates this low level of stress. And then you layer on top the fact that you never get a chance to do the really high quality work that makes you feel useful. This is what I'm good at. This is the job that I'm here to do. And it could be researching or writing a book. It could be preparing presentations for a board. It could be, luckily, if you're like a surgeon, they get to remove all the distractions and actually do their work. But that's the kind of thing that we want to be doing, like focused. This is one thing that we're doing. This is the thing that we're good at really applying ourselves. But we'll do that with a surgeon because we know that someone's life depends on it. But without being flippant, you could kind of make the case that all of our lives depend on it. Right? Like, if, yes, we're not surgeons or many of us are listening, we're not surgeons. I'm sure there are a few surgeons, that's the thing. The quality of your life probably does depend a lot on how you're spending each day. Yeah. Right? So, yeah, a surgeon has a reason to do that. But we kind of need to give ourselves that reason as well, I think. Exactly. And so we want to feel useful and productive. We're no longer, as a species, our history was largely, our productivity was largely due to physical work, right? Hunting, gathering, farming. But now, the product of our work is due to our brains, right? We're knowledge workers. I'd like to call us all cognitive athletes, right? And so, like, that's important because the best athletes, like I was saying earlier, they know they are very targeted training, they are very targeted stimulus, and then they focus on recovery adaptation, getting the most out of their training. Whereas we just spend all day jogging and never think about the recovery that our brains need in order to perform our best. So, well, then what happens is at the end of the day, you've felt very busy and very stressed because you're constantly bouncing around between all these different things. You know, you're in Zoom while you're also writing an email, but you're like not paying proper attention to either of them. And so that process is inherently stressful. And we know that people make more mistakes and errors and feel more stressed when they're interrupted or they have to multitask. And then you're stressed about the fact that you didn't actually do that really high quality, focused piece of work that you needed to do because you were so busy in meetings and multitasking. And so then when you get to the end of your day, you're like, you're stressed about the fact that you didn't do those things. And then you have to try and somehow wind down and go to sleep. So you then may rely on other things that could, that you feel like are allowing you to relax, but could compound that. So it could be social media or it could be, you know, a glass of wine, which then, you know, impairs your sleep and then two glasses of wine. And then the next day, the whole kind of cycle starts again. So I kind of start by thinking about how can I structure the work day so that even if it's just for 30 minutes, I can just get the thing that I need to get done today done. And you do that by, if you can, structuring your day so that whenever you feel best, each of us feels most focused, most alert, most attentive at one specific time of day. And it could be in the morning, it could be in the evening, right, depending on chronotype and other things. During that period of the day, like just get, just set aside half an hour to like do the thing that you need to do. And then you can also set aside time to do the meetings and other things and the emails. We all have to do that. But in between those things, allow yourself time to get to have a break. Can you go for a five minute walk? Right. Can you just like look outside at something green, right? There are studies that show that we can become reinvigorated and less cognitive fatigue just by looking out a window at greenery for 90 seconds, right? So it doesn't necessarily take that much. There are also some nice studies where people feel reinvigorated after five minutes of watching comedy clips on YouTube, right? Just something to completely disengage from the work that you're doing. So can you build some structure in that allows you to do high quality focused work? Can you build in breaks during the day so that you can recover just like in between bouts of sprinting, right? You can't sprint forever. You have to like take a break and then you go back and do it again. And then at the end of the day, if there's anything that's still on your mind that you need to get done or you're to do this, like we know things like mental offloading can really help with sleep. So you write down your to-do list, you write down the things you're worried about. And then that helps people fall asleep. It literally gets out of your mind. You just get it out of your brain, yeah, exactly. And then maybe you can also think about those other things that you might be doing that evening that could impair your ability to sort of wind down and recover. But I kind of think about it in that way that you're sort of like tired and wired thing starts at the beginning of the day. And then there's also like the cycle of alcohol and caffeine, which is very common that can then also impair that process. But just thinking about how we structure, again, how we use our brains, I think, sets us up for the ability to wind down in the evening. I love the idea that if you're feeling tired and wired in the evening, think about how you started your day. It's not just about what's happening in the evening, right? The whole day plays into that. One thing I've often spoken to patients about is this idea of a stress threshold. And that you accumulate all these stress doses in the day. And when you get to your personal stress threshold, and we all have one and, you know, each one of ours can be different depending on our resilience, depending on what we've got going on in our life. But it's when you hit that threshold that the problems often start or when you get close to it, your back goes, your neck goes, you react to an email. You said something about you shouldn't have done or whatever it might be. And I have seen over the years, once people understand that stress threshold concept and go, yeah, so I've been working for a couple of hours, I'm getting closer to it, can I take a five minute break, just move myself away from it. In the day, you just keep, you never let it accumulate to the point where you hit, because once you've hit it, it's hard. You can down regulate with, you know, there's breathing sections in your book that you, you know, different exercises people can do. There's a lot of different kinds of things, but if you can, and if you do have a degree of autonomy over your day, building in those like regular sort of micro breaks, it has an outsized effect in my experience. Absolutely. Especially if you can, so like, like I said, any kind of hard, cognitive work, right, you need to break from just like with, just like with physical work. And it doesn't have to be that long. It just has to be something that completely just, you know, allows you to disconnect. And, you know, even better if you can pair it with just like a very brief exercise snack or period of movement, because like I was mentioning earlier, if we, if we spend a long period of time sitting, mood starts to drop, right, maybe that's what you know, maybe like our stress threshold decreases, right, blood flow to the brain decreases a little bit, you know, we don't have quite the same sort of level of cognitive function. So just like breaking up sitting by using that as a, as a cognitive break, right, if you can go outside or you can just like do anything, you can just like step back. There's multiple things that then happen at that, that moment in time that allow you to then go back into it, you know, just a few minutes later. Let's talk about women's brain health. It's getting a lot more attention these days, very rightly so. Absolutely. I know you've got some, some really quite thought provoking ideas relating to women's brain health through the lens of your 3S model in terms of stimulation. So can you speak to that as a topic? Yeah, absolutely. So one of the, another reason why I think we have this hopeful message for dementia prevention and decreasing population dementia burden in the future is because over the past hundred years, we've seen a decrease in the age specific instance of dementia. And that's measured in a very specific way. But what we hear all the time is dementia cases are going to triple in the next 10 or 20 years, you know, the risk of dementia is constantly increasing. And those things are technically true because the, the world is, you know, the population is living longer. And if you live longer without dying or something else, then you're more likely to get dementia. We know that, but you are less likely to be diagnosed with dementia at the age of 70. Like today, then you ever have been in, in, in previous history and people don't, people don't realize that. So what that means is over time, age specific instance of dementia has decreased. What does that mean? Age specific incidents. So that's exactly what I was saying is so like, if you pick up a specific age, 60 years old, 70 years old, you're now less likely to have dementia at 70 years old than you were 20 or 30 years ago. And I just want to make sure everyone's got this. So why is there this apparent discrepancy then between, you know, rates going up, but our individual risk at any given age going down? It's because we're living longer. So it is true that because now we're more likely to live to be 80 or 90, that yes, the risk of having dementia 80 is lower than it was previously. But because more of us will live to 80, more of us will have to, will have dementia at some point in our lives, but it will just happen later in life, if that makes sense. So both of those, both of those things are happening at the same time, which is complicated. Like I understand it. But what's then interesting is you see that it is possible to move the needle on the incidence of dementia at any given age, which then means that it's probably also possible to move the needle on dementia overall, right? Which just goes back to our fact that dementia is a preventable or some proportion of dementia is a preventable. But when you think about, well, why might this be? Because it kind of goes against some of the narrative. And one is an improvement in cardiovascular health. And this seems to be particularly been beneficial for men, decreasing the age specific innocence of dementia for men, because heart disease risk factors overlap very tightly with dementia risk factors. We've already talked about blood pressure, blood sugar, but smoking, blood lipids play a role here too. We've become much better at treating and preventing heart disease, and that seems to have translated to a lower age specific instance of dementia, maybe more so in men, because men tend to have higher heart disease risks than women. But we do also see some of this shift happening in women as well. And then there are these big meta-analyses that have been done in studies using data from the US, from the UK, from multiple European countries. And I wonder if some of what we're seeing, particularly in women, is the changing role of women in society, which has been overwhelmingly beneficial. So if you think back to, I mentioned Warner Shieh's Seattle Longitudinal Study. And one of the things that they looked at in the Seattle Longitudinal Study was environmental enrichment, or an enriched environment, which basically meant how complex and cognitive stimulating is the world that you exist in, largely related to your work and your hobbies. And the more enriched or complex your environment, the lower your risk of dementia or cognitive decline in the Seattle Longitudinal Study. But there were a group of individuals who had low environmental complexity and a higher risk of cognitive decline dementia, and they were all overwhelmingly women, which was the housewife. And this in the 1950s was a very traditional thing, right? And the way that they measured these things and the way they wrote about them is partly of their time, right now, 60, 70 years ago. But something that they saw in that study was that that environment was not necessarily as stimulating or complex as the work environment or the other people might have access to. But we've seen both within, you know, Westernized societies, but also globally, as education has become more accessible and equitable to women in particular, dementia rates and dementia risks have decreased, right? That's one of the reasons why education is actually the risk factor in the Lancet Commission report that is the biggest number, 7% of dementia is related to education. And then we think about the work environment. So women's presence in the workplace only really started to expand in the 1970s. This is based on like US labor and statistics data. And so there's been this big shift from, you know, what is maybe the potential for a less cognitively stimulating environment. And I realized that that doesn't have to be the case, right? People can, you know, be primarily at home and most of their work and commitments are at home with their children or family or family members, right? And that's what they do. And that can be incredibly stimulating and incredibly enriching and incredibly satisfying, of course, right? So we're talking like averages and maybe how things looked 60, 70 years ago. But as those things have shifted, right, women have been allowed access to more complex, higher power jobs and more education. Again, both within Westernized countries and globally, we've seen age specific instances of dementia decrease. So I think as society becomes more equitable across the sexes, we may start to see some of those benefits pay off in terms of dementia rates. Because right now, right, about two thirds of Alzheimer's disease burden is in women, right? We know that. But those statistics come from women who are largely of that period. And so I think, so my hope is that, yes, we should do a whole bunch of additional research where women have been left out of neuroscience and neurology research for decades. And I'm so happy that that's changing. But I also wonder if, like, this shift in society will pay off in a beneficial way because of the stimulus that you can get from work and education that now more people have access to. It's so fascinating to think about that. And it all feeds back to this idea that the stimulus to the brain is the most important thing. Going back to women's health again, and specifically women's brain health. How do you think about the menopause and the hormonal changes that occur in the menopause and risk of cognitive decline? This is an area that still right now is hotly debated. Yeah. And this is probably the most challenging part of the book for me to write, mainly because I wanted to be very evidence based. But equally like women should feel supported by men. I am absolutely a feminist and I want that to come across. And so, first of all, there's a whole bunch of studies that need to be done. Things like Lisa Mosconi's care initiative funded by the Welcome Trust. Like, fantastic, like really excited. I'm really excited to see those things happen. But right now we know that just like really simplify it. If you live long enough as a woman, all women will experience the menopause, right? But only about 20% will experience dementia. So that means that that decrease in hormones is not going to automatically result in cognitive decline dementia. Exactly. We know that from the data. Now, if somebody is experiencing symptoms related to perimenopause and menopause, particularly vasomotor symptoms, you know, night sweats, hot flushes, you know, problems with sleep, even cognitive changes, which do happen. Then I think things like menopausal hormone therapy can be incredibly powerful by improving quality of life, by improving sleep, by improving your well-being, sexual function, mental health, how likely people are to engage in other important aspects of lifestyle. You know, critically important. And that's what the current guidelines say, that to address symptoms and quality of life, or menopausal hormone therapy, is an incredibly powerful tool. And for other things, you know, bone health, cardiovascular health, when used, you know, in that way, in collaboration with your physician. But the hormonal changes don't seem to be enough to explain cognitive changes. And actually, the data seems to suggest a couple of things. The first thing is that vasomotor symptoms are better predictors of cognitive changes than hormonal shifts are. And for people who don't understand the term vasomotor? Yeah, so like I mentioned, the hot flushes, night sweats, that kind of stuff. Like those kind of symptoms that the women get during the menopausal transition. And there was, so like one example is there was a very interesting study where they used nerve blocks to, like you sort of like inject an anesthetic around nerves in the neck, which decreases some of these symptoms. And in those, who those who had significant symptoms, and they saw that by blocking these nerves that affected vasomotor symptoms, they saw improvements in cognitive function, nothing to do with hormones, right? And this is probably because changes in body temperature regulation and blood flow and, you know, activation of stress hormones. These can then affect certain parts of the brain that might affect cognitive function. So we know that there are a whole host of lifestyle factors that relate to those symptoms, right? So we know that you can improve them by improving diet quality. You can improve them by improving physical activity, right? So yes, hormones play a role. And that is part of that. But we know that other lifestyle factors are critically important as well. We also know that this is the period when the risk of Alzheimer's disease diverges between men and women, right? And so it seems like the menopausal transition is a risk amplification period. And what I mean by that is that other risk factors for dementia and cognitive decline, their effect seems to get larger in women as they enter that transitional period. So one example is there was a study done in the U.S. where the largest cognitive changes seem to be in women who had evidence of metabolic disease. So that's, again, we know the metabolic disease of risk factors for dementia and cognitive decline. During that transition, in those who had metabolic disease, they saw a bigger impact on their cognitive function. So I tend to think of it as a risk amplification period such that if we think about all the things we've talked about today, any ongoing risk factors may have a larger effect as you enter menopause. But that also means that those are things that you have controlled over. Because by the same token, we know that if you improve your diet quality or if you improve your movement, then you can help control those symptoms and those symptoms are the things that correlate with changes in cognition. And the final piece that I think is important is that it is a transitional period. So there was the Swan study in the U.S. found that in women who did experience some cognitive changes during the menopausal transition, they actually went back to almost exactly where they were beforehand, once the transition was completed. So if you do experience some cognitive changes during, you know, perimenopause, menopause, it's not, it is a transition. They may well improve later. And of course, like in the meantime, if menopausal hormone therapy or other lifestyle, environmental interventions improve that, that's great and you should absolutely do that to focus on quality of life and a whole host of other things. But it's not guaranteed that any changes are going to be permanent. And there are several cognitive functions that continue to improve as we get into our 50s, 60s and 70s and well-being as well in both men and women, where, you know, the components of crystallized intelligence, which is a fancy word way for saying wisdom, you know, elements of taking in a bigger picture, thinking about all the things that we know, putting them in context, they actually improve as does well-being. So a different type of cognition. It's a different, yeah. So cognition doesn't get worse as we go older, it just shifts, right? So some things change, right? And you can measure reaction time or something. Maybe that decreases, but we get better at other things. So like all that to say that this is an incredibly important topic and I want everybody to feel amazing every day, regardless of where they are in that period. But we've kind of boiled it down to two groups who are like hormones to everything and we need hormonal, like menopausal hormone therapy, because if we don't, we're going to have cognitive changes and experienced dementia. And the other group was saying, well, there's no evidence for any of that. And the second group is actually more right, I will say, based on the available data, because there are studies where they give bio-agenetical hormones to women in the menopausal transition and they don't see any effect on cognitive function, right? Like the keeps trial keeps cog down in Canada. But they can have a massive impact on qualitative life and all those other things that I mentioned. So it is incredibly nuanced. And the main thing that I've seen is that there have been two sort of very black and white pictures of it. And the person who doesn't benefit is the woman in the middle who's just like, I just want to feel better. I want my brain to work better. And that's the person that I really feel for. I hope that they understand that there are all these different parts and actually a whole bunch of things that they can potentially do, including related to hormonal therapy, if that makes sense for them. But also there's a lot of power to improve physical health, you know, start resistance training, which we know can improve symptoms, you know, start to focus on sleep if you can, or maybe the hormones help you sleep and then you sleep better. So all these things should be kind of taken into account when we're having these complex conversations about menopause and cognitive function. Hence the importance of women having better access to well-educated healthcare professionals who know the nuances, because that's something probably that hasn't been there. But as you said at the start, it's kind of like, well, if you live long enough as a woman, you're going to go through the menopause. So everyone has hormonal changes and a hormonal decline, but not everyone gets dementia. Right. So it can't just be that that is solely responsible on could genetics play a role, could other factors play a role. It is incredibly nuanced. Of course, we want more data and more research. Let's talk about exercise. I know we've spoken before about the importance of exercise for our brains. Perhaps you can give us an overview of that. But today, I thought it'd be interesting to specifically go into what do the different types of exercise do to our brain? And also, is it fair to say that exercise just fits in that second S supply? Because I kind of feel some exercise could count as stimulation. And of course, like we've already said, and if you exercise enough, it's going to help you with your support and recovering from it. Yes. Yes. So lots of yeses. So one of the potential downsides of thinking about and I've experienced this when trying to explain the 3S model to some people is they expect that any given activity only fits in one bucket. When of course they don't. So I think that there were types of exercise that could absolutely hit all three Ss at the same time. Right. So if we're thinking about big leverage points, there are things that we can do that hit multiple buckets at the same time. Right. So like that's definitely something we could take into consideration. But when you think about exercise in the brain, it largely comes in three flavors. So like aerobic type exercise, resistance training or weightlifting, and then co-ordinative exercise. And in the research, they might call it open skill exercise and I'll get to that kind of last. But the first, the most important thing to say first is that any physical activity that you do will improve cognitive function. If you're starting from a low level of initial physical activity, right? So we know that the more steps you take per day, the lower your risk of dementia up to sort of somewhere around 8 to 12,000 steps per day. The first time we really saw that exercise could improve the structure and function of the brain, particularly the hippocampus, which is important for memory and is vulnerable and Alzheimer's disease, was with a brisk walking intervention, brisk walking 40 minutes, three times a week. So like any way you start, it just like starts you moving your body regularly is great. But aerobic exercise, across the scale of intensities, because at the top, at the low end you might just have like walking, and at the top end you might have high intensity interval training, you know, where you do sprinting on a bike or a treadmill or a row machine for some period of time, and then you recover and you do that, do a few rounds. Those types of exercise seems to be particularly beneficial for the gray matter of the brain, which is sort of like the wrinkly outside, the cortex as well as like some stuff inside like the hippocampus, and particularly beneficial for memory. So if you're looking at different cognitive functions and at the higher levels of intensity, we see greater benefit probably because of the production of lactate, which has been sort of derided as a molecule that we want to avoid that somehow bad for us for long periods of time. But what we're seeing increasingly is that it's a very powerful signaling molecule, particularly in the brain. So when you make lactate, you feel the burn, right, and lactate is part of the buffering system that we use when we're doing, you know, anaerobic type exercise or like very high intensity exercise. And lactate goes into the brain and it switches on the production of BDNF, brain-derived neurotrophic factor, which supports the function of recently activated neurons. So like supports the process of neuroplasticity, which is what is underpins, you know, learning and improving function in the brain. So, and again, when you look at studies where they do high intensity interval training interventions for long periods of time, you see improvements in the structure and function of the hippocampus in particular. So you can see that on a brain scan, then you also see improvements in memory specifically. So that's like the aerobic bucket. Then the next bucket is resistance training. So a lot of what's different across these different types of exercises is what gets released while we exercise. And so while we might think about something like lactate, brain-derived neurotrophic factor with aerobic type exercise, with resistance training, we release more things like IGF1, insulin-like growth factor 1, which is really critical for white matter. So this is something that we see even in babies born preterm who are at risk of injury to their white matter and then associated increased risk of things like cerebral palsy. And IGF1 is really critical for the white matter. One reason why babies born preterm have issues with white matter development is because the placenta normally provides the IGF1 that they use to grow their white matter. But then we see the same thing later in life where if you do resistance training, you release IGF1 and the structure and function of the white matter improves. So it's critical throughout the entire life that this is a very important molecule for white matter. So the white matter kind of sits in the middle of our brains. It makes about 60% of the human brain. And it's responsible for these fast connections between different parts of the brain and the brain and the body. And so when we do resistance training and we do the randomized controlled trials, you take older individuals, you have them do a resistance training program for a few months, you see improvements in the structure of the white matter and then improvements in sort of like overall cognitive function, but particularly things like executive function or rapid decision making. And so that's because of the effects on white matter, we think. And actually white matter changes, the changes in structure and function of white matter better predict cognitive decline and loss of cognitive function than some other things that we've tended to focus on more as a community like amyloid protein in the brain. White matter changes seem to precede that and actually predict some of those cognitive changes better. So that's where resistance training becomes really important. And then so like the final piece is this co-ordinative movement. So it's, you know, there are now a huge number of studies where you take two different types of exercise that have the same physical intensity, right? They raise the heart rate the same amount, for example. But those that then have a complex movement component on top seem to have an additional benefit for the brain. So it's like comparing dancing to cycling or, you know, they've done table tennis and badminton compared to cycling and they've done running around an obstacle course compared to just running around a track. And presumably the table tennis, the badminton, the dancing, these are these complex tasks where as well as fitness, you're doing other things as well. So it's a more complex stimuli to the brain. Exactly. Yeah. So all activity is great for the brain, right? But there seems to be an even greater benefit and you can measure this in terms of cognitive function. You can measure this in terms of sometimes they've looked at brain scans, like changed on a brain scan that if you have a complex movement component on top of the physical component, there's additional benefits for the brain. So we're talking dancing, martial arts, ball sports, racket sports, any kind of team sport. And what all these things involve is learning complex motor skills, movement skills. But also often there's a social component. There's also a requirement to respond to the environment, respond to other people, react to the ball being hit at you and strategize quickly and in real time. So if you're playing tennis, I'm a terrible tennis player. So like not me playing tennis, but a good person playing tennis. You're trying to not only respond to the ball being hit at you and moving your own way around the court, but you're trying to manipulate the positioning of your opponent so that you can hit the ball past them, right? And you're doing this at high speed. And so, you know, challenging multiple senses. And so it's these kinds of complex movements that seem to have an outsized benefit for the brain. So again, I've, you know, across the things I mentioned, there could be 12, 20 different things that you could do that, right, challenge the brain in the same way. So like pick one that you enjoy. And if we are thinking about like really high impact or activities that maybe hit all the different nodes of the 3S model, right? You might think of something like dancing or paddle or pickleball in the US, right? There's a social component. There's a complex movement. So you're getting physical activity. You're getting cognitive stimulus. You're going to sleep better afterwards, right? All of those things you're doing at the same time. So when people do inevitably ask me, well, what's the one thing I should do? These kinds of activities are the one thing that the eye would, if you're going to pick one thing, pick a new sport that requires you to use a, to learn a complex skill and do it in a social setting. You've hit all those different things, everything in one go. God, I love that. So many thoughts came up for me. First thing is to reinforce this message that the brain can adapt to any age. Yeah. Last summer, my son broke his wrist at the end of the summer holidays and had to wear a cast. And one of the things we liked to do, particularly in the summer, we had this outdoor table tennis table. And we basically decided with a bit of cajoling from me that we were going to play left-handed table tennis while his cast was healing. Yeah. I'm kidding you. But the first time is, oh, man, this is, you know, we're decent players with our right hands. Yeah. And it was a bit tricky with the left hand. Literally within about two days, we're having good rallies. And after about 10 days, he was going and playing table tennis at school and he was beating other people who were playing with their right hands. But he's a decent player. But I just thought, wow. And I think that speaks to this broader point, doesn't it? About how quickly our brain can adapt and respond. I've also read some stuff that perhaps learning it with the weak hand then improves your ability with the stronger hand because different regions of the brain are connected. So that was one thing I thought about. The second thing I thought about was in relation to this, I know we're not spoken today about had room and cognitive reserve. I know we've spoken about that before and obviously you write a lot about it in the new book. I thought about know about Djokovic. Oh, yeah. Okay. So he's still getting to Grand Slam finals. I think he's 38. He's in phenomenal shape, arguably the greatest tennis player of all time. I'm wondering if as a thought experiment, if he was to retire, let's say at the age of 40. So for many, many years, he's been learning these skills, right? And also he pays attention to detail. He leaves no stone unturned in his desire to get better, whether that's eye training, juggling before he might go out onto the core, mindsets, nutrition, movement, recovery, all these things that you probably see with your Formula One drivers, right? So let's say at 40, he just stopped. Hypothetical scenario. So he's had all this incredible stimulus, supply and support for the first 40 years of his life. So he probably has a huge amount of cognitive reserve and headroom. If the day after he retired, he, I'm almost certain he wouldn't do this. Let's say the day after he retired, I use the word retire because this is kind of what happens to people at 65, right? He stopped doing anything. So he just sat at home in his nice house, watching box sets on Netflix. They're not even called box sets anymore, are they? Streaming. He was streaming series on Netflix. Is it fair to say that because he's worked that capacity for so much, it will take him longer to have a decline in function that is no-despore compared to someone who has not stimulated their brain as much? Or do we not know? Well, so there's two competing parts of this that make me say maybe. And I'll explain them both. So because you've built so much additional capacity with all this training, do you then have a longer trajectory before you've lost so much function? And there's probably two areas of this. One could be tennis-specific skills. Even if he doesn't play for 10 years and when he's 50, he's still going to be a better tennis player than me. Even if he's, although we're roughly the same age, so maybe that's about comparison. He's still going to be a better tennis player than some 20-year-old off the street. But the amount of skill that he's lost will be massive. The relative loss of skill will be huge because he had so much previously. But if we think about this more broadly in terms of broader cognitive decline and dementia, then I'll briefly go back to the example of education and educational attainment. So when we look at, and sort of like his primary education has come on the tennis court, if that's his primary mode of stimulus. And so when we look at cognitive trajectories over a lifetime, those who have higher levels of educational attainment, they have a higher peak of cognitive function, right? It happens slightly later. They have a lower risk of dementia and they tend to get dementia later because they've started at the same peak. But the early stimulus doesn't change the rate of decline, right? So if you remove that stimulus, right, you're still going to decline, right? It doesn't prevent that. There are some studies that suggest that those who have the highest levels of educational attainment or the highest job complexity lose relative function, like relative to where they were. They lose it faster after retirement because their body was so used to performing at a high level and having high levels of stimulus that they actually have a higher drop-off rate. So one could say that Novak Djokovic's tennis-related skills are going to drop off faster than most other people's because he had so much and he was so used to getting so much so the relative drop-off rate is going to be faster. And so there's a few different things that you have to balance there. One is, yes, you build overall capacity, but the system may adapt such that it requires greater ongoing stimulus in order to maintain that capacity, if that makes sense, because that's what you have more to lose because of what you've built. So you do have some buffer, but it doesn't mean that you can rest on your laurels because you build this capacity that ongoing stimulus is required. And then where you end up in terms of that final trajectory, it's probably going to depend on the whole kind of network. So it's actually quite a complicated answer to your question because you're going to have all these competing things going on. Yeah, it's interesting to think about that, you know, no matter what your job is, no matter where you are, you know, you got to keep using it, right? Basically, like you said at the start, use it or lose it, maybe overly simplistic, but people get that, you know, you have to keep giving your brain a reason to adapt. And, you know, as it happens, I think he speaks maybe seven or eight different languages. I think he's a very, very rounded and intelligent individual. So I suspect I can't imagine he's going to retire and then do nothing. But it's an interesting thought experiment. Just going back to those three types of exercise. I just want to, as you said, the practical take home is move, right? And, you know, and as you said, I think you said dementia risk goes down up to about 8 to 12,000 sets. Doesn't mean you can't do more than that, but you may not get the benefits in the same way. Or you just, you don't see additional benefit. You don't see additional benefits. When it comes to lactates, and I think you spoke about in the context of high intensity movement, the lactate has particular benefits for the brain. That doesn't mean that people shouldn't do low intensity training because, you know, keeping your lactate low for an hour and a half walk also has benefits for mitochondria and, you know, your ability to burn fat and your metabolic health, right? So, you know, how do you see that? I want to make sure that everyone listening understands that when it comes to brain health, how do they interpret those three buckets that you spoke about and introduce it into their lives? Yeah. So, if I'm honest, I feel like people in the health sphere, podcasting sphere, spend way too much time talking about exercise strategies that are only relevant to elite athletes. And people who spend all their time exercising. If you can only exercise in a formal way two or three times a week, which is the case for most people, then getting, like, getting in a little bit of structured resistance training and maybe the occasional sprint session, right? That's where I would focus. The rest of the time, I'd just be like, during the day, how much can I just move around as much as possible? Like, break up periods of sitting, take the stairs, walk for 20 or 30 minutes a day. I have in the book, I have this movement funnel that I think people should work through. And the first level is snack, which basically is just break up periods of being set into during the day. How do you do it? Stand up, walk around, take the stairs, anything. Then the next level is propel, which is basically just do some low level movement or whatever you can. And so it can be cycling, it can be rowing, it can be walking, it could be propelling a wheelchair, right? Anything like that. Low level activity. That's what most of us should spend most of our time doing. But just because it's part of our day. Then on top of that, I would layer in some kind of structured higher intensity stuff. So maybe it's, right, you go for a walk and then you make it brisker. And then towards the end, maybe you just like sprint for a little bit or something. You just like layer on little bits of intensity because we know that that has additional benefit. And then once or twice a week, I'd go and do some kind of resistance training. And that's what we think the minimum effective dose to build strength, muscle mass, and then also improve brain health. At least once a week, probably. Very basic. Six or eight exercises that cover the whole body, three sets of eight to 12 reps, like the basics. Like maybe the best is twice a week if you can. But then in reality, if you're going to try and tick multiple boxes in just like a normal person schedule, I would make some of my aerobic type exercise something that's more cooperative, right? So like rather than going for a jog, go and play football, go and play table tennis, go to a dance class, right? So you're getting that aerobic training, but you're also getting additional benefit and you know, all the other things that we've talked about. But that's it. Super helpful. And that's one of the things, Tommy. I've always liked about your approach. It's very, very pragmatic and practical. It's really trying to look at the big picture and see where most people are at and acknowledging that we have this healthcare crisis. And actually, if we make it too difficult and if people feel it's too difficult in the context of their everyday life, they're not going to do anything. It's going to be paralyzing, right? Yeah, I think sometimes, I think sometimes what happens is that researchers talk about optimal or what they've seen in the lab, which is great. And I love reading about all that stuff, but it also needs that conversion to the man or woman on the street who's just trying to get a little bit healthier, right? Tommy, I could talk to you for hours. And there's just, of course, because you've written such a thorough book, we barely scratched the surface of what's in it. I want to reiterate, I think it's one of the best health books I've read. It's so good. I love the title. I love the subtitle. The simulated minds future-proof your brain from dementia and stay sharp at any age. On a personal level, how is it being for you doing all these interviews about your book? You're travelling a lot. You're doing a lot of podcasts. That takes its toll. Yeah, it's... Well, maybe before I get to that part, I wanted to say that this book exists because of you. And I wanted to say thank you for that. So for two main reasons. The first being that you were the first person that I think I really spoke to about wanting to write a book. Several years ago, right? We talked about this. And I had various ideas and those ideas have shifted over time, but you were the first person to kind of encourage me to do that, and I really appreciated that. And then one of the previous episodes that we did, I think it was the second time I was on the podcast. There was somebody, she used to work at Ebrie, which is a Penguin imprint. She's called Arne Hayes. She now works for Hay House. But she sent me an email and was like, I listened to your episode with Rangan. I think you should write a book. And that was the first time that I actually took it seriously and started to work on a proposal and all the kind of stuff that kind of brought us to here today. So like, thank you. This exists largely because of you. And I wanted to really... Oh, well, I really appreciate that story. And it's my absolute pleasure. And I'd say no credit for how great the book is. But thank you. So yeah, then writing the book, I loved it. It's hard. It's a very different type of writing from how I normally write, which is very academic and dry and all that kind of stuff. So like, it took me a while to kind of find that voice. But it's still, you know, reading research, thinking about ideas, how to bring them together, how to make them practical, which was really important to me. I loved it. But the hard part is then you have to go out and you have to tell people about it, right? And you obviously have done a lot more of this than I have. But yeah, in general, I quite like being at home. I like working with the people that I have in my lab. I like spending time with my wife and my dogs. And it is also an incredible experience to come out, like come and visit you and talk about these things and do some of the shows that I've done. You know, be on podcasts that I've listened to for more than a decade is an incredible experience. But you're right. There's jet lag, travel, you know, stress, not being able to do the things that you normally do to kind of like look after your health. It's definitely been a bit of a roller coaster and whirlwind. And I'm incredibly grateful for all of it. But you're right, like there's only so much of this that one person can do because it does, it takes a lot of effort. And if we look at that, I just had a thought there. If we look at that through your 3S model, which we can apply on a daily basis, a weekly basis, but I guess you could also apply it across a period of months. Right. So we could say, let's forget about the writing of the book just for a moment. Let's say all this travel and being asked questions about, you know, it's such a thorough book. People could ask you something from anywhere and you've got to answer questions and have something to say. Right. You're getting a lot of stimulation. I know you, so you'll be to the best of your ability trying to make sure the supply is good. So you'll try and eat well. We haven't spoken about blood flow restriction today, but we're going to do that next time for sure. Right. So you'll be doing things about exercising and making sure that there's enough flow to the brain. Yeah. But I guess when I think about support and how you can rest and sleep and integrate all of this into your brain, and your, on your, on your life, I guess the thing that comes to me is once this is done or this initial batch, have you planned in a period of prolonged support so you can adapt, rest, sleep, get all the benefits? You know what I mean? Yeah, absolutely. And that is that. That is definitely in the plan. Like, you know, my wife and I, we've sort of sat down and there's been a big burden on her to like, there's more that she has to do when I'm not at home, right? So it's been a burden on both of us and then figure out like, when's this hopefully going to wind down? What are we going to do to kind of take some time to ourselves and spend time together? So like, that's a big part of it. But I think that your point is really, really important because all of these things integrate over incredibly long time periods, right? Decades over which that we can influence our health, you know, both good and bad. But what it means is that you don't need to worry about it on as much on like a day to day basis. Yeah. Yeah. If you, if you can then use it to say, oh yeah, today I'm going to do a little bit of this, I'm going to do a little bit of this. That's great. But I certainly go into this knowing, hey, do you know what, there's going to be a few months where I'm not going to move as much as I would otherwise. And I'm not going to sleep as well as I would otherwise. Actually, because I spend so much time, you know, creating that foundation and I know I'll go back to it, you know, I know I'll be just fine. And I think that that's something we can give ourselves a little bit of grace on that as well because we just, it's not always going to be perfect. We're not going to be able to do everything and know that these things integrate over long periods of time. For that person who has listened to us, Tommy, and is really, really scared that they're going to get dementia because a lot of people in their family have had it. And let's assume they don't have one of these predeterministic genes. Yeah. Okay. What are your final words for that individual? I would want them to know that we each have huge power over our long-term risk of dementia and our cognitive trajectory. And regardless of where a family history may come from, and sometimes it's genetic, it could be related to apo-e genotype, which is a common risk factor for dementia. It could be related to, you know, there's a whole host of genes that come together. You know, thousands of genes, you get like risk increases and decreases related to that. A lot of family history of dementia and risk comes from shared environments and shared behaviors. Across all of those, you can dramatically decrease your risk by starting to engage in some of the things that we've talked about today. And I think the two things, or maybe three things that I would want to say is one, know that this is possible, right? Know that you have massive capacity to change cognitive function that decline is not inevitable. Then know that just starting with very simple things can have a big impact, right, for the reasons that we talked about. And know that even if you have some previous risk, you can mitigate the majority of that risk, regardless of where that risk comes from by engaging in those behaviors. And maybe that's one way that you might look at it. So if you have a family member who had dementia, my grandfather died of dementia. I know that so far, Knocconwood, I've avoided his major risk factor. He was an alcoholic, right? So if you think about my mother, my grandparent, sibling had cognitive decline dementia, what were the things that they did or didn't do that maybe map onto some of the stuff we've talked about today? Maybe that's a place to start, right? Because those shared risk factors were a lot of things that sort of come across in families. And then know that by changing that, by starting to move that needle, and it's just, you know, I say in the book, everything counts, right? Each little bit that you can do to work on that will have an impact. Know that you have control over that. And focus on the things that you have the ability and resources and time to focus on. Because anywhere you start, right, in the model, any way you start, the whole network starts to shift in your favor. Tommy, I love it. It's a very hopeful message. It's a very empowering message. Guys, get the book. It's really, really good. The stimulates in mind. Tommy, thanks for coming back on the show. And let's do another one very soon. Yeah, I would love to. Thanks so much for having me. A blast, as always. Really hope you enjoyed that conversation. Do think about one thing that you can take away and apply into your own life. And also have a think about one thing from this conversation that you can teach to somebody else. Remember, when you teach someone, it not only helps them, it also helps you learn and retain the information. Now, before you go, just wanted to let you know about Friday 5. It's my free weekly email containing five simple ideas to improve your health and happiness. In that email, I share exclusive insights that I do not share anywhere else, including health advice, how to manage your time better, interesting articles or videos that I've been consuming, quotes that have caused me to stop and reflect. And I have to say, in a world of endless emails, it really is delightful that many of you tell me it is one of the only weekly emails that you actively look forward to receiving. So if that sounds like something you would like to receive each and every Friday, you can sign up for free at drchatterjee.com forward slash Friday 5. 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