Neuroscientist: Most Women Are Raising Their Dementia Risk (Without Knowing It)

1. 0:01 – 2:35

   Why dementia can rise overall while your age-specific risk falls

   1. RCDr. Rangan Chatterjee0:01

      Let's talk about women's brain health.

   2. TWDr. Tommy Wood0:04

      Mm-hmm.

   3. RCDr. Rangan Chatterjee0:05

      It's getting a lot more attention these days, very rightly so.

   4. TWDr. Tommy Wood0:09

      Absolutely.

   5. RCDr. Rangan Chatterjee0:09

      Um, but I know you've got some, some really quite thought-provoking ideas relating to women's brain health through the lens of your three S model in terms of stimulation.

   6. TWDr. Tommy Wood0:19

      Mm.

   7. RCDr. Rangan Chatterjee0:19

      So can you speak to that as a topic?

   8. TWDr. Tommy Wood0:21

      Yeah, ab- 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 incidence of dementia, and that, that's measured in a very specific way. But what we hear all the time is dementia cases are gonna triple in the next 10 or 20 years. Um, you know, the, the, the risk of dementia is constantly increasing, and those things are technically true because the, the, the world is, you know, the population is living longer. And if you live longer without dying of 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 n- like today than you ever have been in, in, in, in previous history. And people don't, people don't realize that. So what that means is, over time, age-specific incidence of, of dementia has decreased.

   9. RCDr. Rangan Chatterjee1:30

      What does that mean, age-specific incidence?

   10. TWDr. Tommy Wood1:32

       So that's exactly... So that's ex- 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.

   11. RCDr. Rangan Chatterjee1:42

       So w- just... And I just wanna make sure everyone's got this. So why is there this apparent discrepancy then between, you know, rates going up-

   12. TWDr. Tommy Wood1:49

       Yeah

   13. RCDr. Rangan Chatterjee1:49

       ... but our individual risk at any given age going down?

   14. TWDr. Tommy Wood1:52

       It's because we're living longer. So it is true that, um, because now we're more likely to live to be 80 or 90, that, yes, the, the, the risk of having dementia at 80 is lower than it was previously. But because more of us will live to 80, more of us will have d- 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 th- both of those things are happening at the same time, which is complicated. Like, I, I understand it. But what's then interesting is, is you see that it is possible to move the needle on the incidence of dementia at any, any given age, which then means that it's probably also possible to move the needle on dementia overall, right?

   15. RCDr. Rangan Chatterjee2:35

       Mm.

2. 2:35 – 3:35

   Cardiovascular health improvements and the decline in dementia incidence

   1. TWDr. Tommy Wood2:35

      Which just goes back to our, the fact that, uh, dementias are preventable or some provot- proportion of dementias are preventable. But when you think about, well, why might this be? 'Cause it, 'cause it kind of goes against some of the narrative, and one is an improvement in cardiovascular health, and this seems to be partic- have particularly been beneficial for men, decreasing the, um, age-specific incidence of dementia for men because, uh, uh, heart disease risk factors overlap, um, very tightly with dementia risk factors. We've already talked about, um, blood pressure, blood sugar, but, um, smoking, um, 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, a lower age-specific incidence of de- of dementia. Maybe more so in men because men tend to have higher heart, you know, heart disease risks, uh, than, than women. But we do also see some of this shift happening in women as well, and there were these big meta-analyses that have been done in studies using data from the US, from

3. 3:35 – 7:00

   Cognitive stimulation, education, and women’s changing roles as a protective factor

   1. TWDr. Tommy Wood3:35

      the UK, uh, from multiple European countries. And I wonder if some of what we're seeing, particularly in women, is ch- uh, the changing role of women in society, which has been, uh, you know, overwhelmingly beneficial. So if you think back to, uh, I mentioned, uh, Warner Shaw's, uh, Seattle Longitudinal Study. Um, and one of the things that they looked at in the, in the Seattle Longitudinal Study was, um, environmental enrichment or an enriched environment, which basically meant how complex and cognitively 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, um, individuals who had low environmental complexity and a higher risk of cognitive decline dementia, um, and they were all overwhelmingly women, which was the housewife. Um, and this in the 1950s was a very traditional thing, right? Um, and the way that they measured these things and the way they wrote about them, you know, is part- 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, um, stimulating or complex as, you know, the work environment or the, that other people might have access to. But we've seen both within, you know, Westernized, um, societies but also globally, as education has become more accessible and equitable, um, to women in particular, dementia rates and dementia risks have decreased, right?

   2. RCDr. Rangan Chatterjee5:23

      Mm.

   3. TWDr. Tommy Wood5:23

      That's one of the reasons why education is actually the m- the, the risk factor in the Lancet, uh, Commission report. That is the biggest number, 7% of dementia is related to, to education. And then we think about the work environment. So, um, wom- like women's presence in the workplace only really started to expand in the 1970s, and this is based on like US labor and statistics data. Um, and so there's been this big shift from, you know, what was maybe, um, the potential for a, a less cognitively stimulating environment and, and, and I realize that that doesn't have to be the case, right? People can, um-You know, be primarily at home and, you know, the, the most of their work and commitments are at home with their children or family or family members, right? And that's, that's, that's what they do, and that can be incredibly stimulating and incredibly enriching and in- incredibly, um, like satisfying, of course. Right? So we're, we're talking like averages and maybe how things looked 60 to 70 years ago.

   4. RCDr. Rangan Chatterjee6:29

      Yeah.

   5. TWDr. Tommy Wood6:29

      Um, but as those things have shifted, right, um, women have been allowed access to more complex, um, higher, higher powered jobs and, you know, more education, again, both within Westernized countries and globally. Um, 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. 'Cause right now,

4. 7:00 – 7:52

   Why women carry more Alzheimer’s burden—and why that may change

   1. TWDr. Tommy Wood7:00

      right, about 2/3 of d- of Alzheimer's disease burden is in women, right? We know that. But the, those statistics come from women who are, who are largely of that period, and so I th-

   2. RCDr. Rangan Chatterjee7:10

      Mm.

   3. TWDr. Tommy Wood7:11

      So, uh, my hope is that, yes, we should do a, a, a whole, um, bunch of additional research where, you know, 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, in society will pay off in a beneficial way, uh, because of the, the stimulus that you can get from, from work and education that now more people have access to.

   4. RCDr. Rangan Chatterjee7:41

      It's so fascinating to, to think about that, and it all feeds back to this idea that the stimulus to the brain is the most important thing.

   5. TWDr. Tommy Wood7:50

      Mm-hmm.

5. 7:52 – 10:17

   Menopause and cognition: separating hormones, symptoms, and dementia risk

   1. RCDr. Rangan Chatterjee7:52

      Going back to women's health again, and specifically women's brain health, how do you think about the menopause-

   2. TWDr. Tommy Wood8:00

      Mm

   3. RCDr. Rangan Chatterjee8:00

      ... and the hormonal changes that occur in the menopause and risk of cognitive decline?

   4. TWDr. Tommy Wood8:08

      This is an area that still right now is, is hotly debated.

   5. RCDr. Rangan Chatterjee8:13

      Yeah.

   6. TWDr. Tommy Wood8:13

      Um, and this is probably the most challenging part of the book for me to write, um, mainly because I want it to be very evidence-based, but equally, like, women should feel supported by men.

   7. RCDr. Rangan Chatterjee8:27

      Yeah. 100%.

   8. TWDr. Tommy Wood8:27

      I am absolutely a feminist, and I, and I want, I want that, I want that to come across. Um, and so first of all, there's a whole bunch of studies that, that need to be done. Um, things like, uh, Lisa Mosconi's Care Initiative-

   9. RCDr. Rangan Chatterjee8:43

      Mm

   10. TWDr. Tommy Wood8:44

       ... funded by the Welcome Trust, like fantastic. Like really excited. I'm really excited to see those things happen. Um, but right... So right now we know that, um, just to 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, um, hormones is not going to automatically result in cognitive decline dementia, right?

   11. RCDr. Rangan Chatterjee9:15

       Exactly.

   12. TWDr. Tommy Wood9:16

       Right.

   13. RCDr. Rangan Chatterjee9:16

       Yeah.

   14. TWDr. Tommy Wood9:16

       We know, we know that from the, from the data. Now, if, um, somebody's experiencing symptoms related to perimenopause or menopause, particularly vasomotor symptoms, you know, night sweats, hot flushes, um, you know, problems with sleep, even s- even, even cognitive changes which, which do happen, then I think things like menopausal hormone therapy can be incredibly powerful by im- by improving quality of life, by improving sleep, by improving, uh, your wellbeing, 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, um, to address symptoms and quality of life, right, menopausal hormone therapy is a, is an incredibly powerful tool. And for other things, you know, bone health, cardiovascular health when used, you know, i- in that way, i- in, in, you know, in collaboration with your physician. But the hormonal changes don't seem to be enough to explain cognitive changes, and,

6. 10:17 – 11:30

   Vasomotor symptoms as a better predictor than hormone levels

   1. TWDr. Tommy Wood10:17

      and actually, um, the data seem to suggest a couple of things. One is that vasomotor symptoms are better predictors of cognitive changes than hormonal shifts are.

   2. RCDr. Rangan Chatterjee10:27

      And for, and for people who don't understand the term vasomotor.

   3. TWDr. Tommy Wood10:30

      Yeah. So like, like I mentioned, the, the hot flushes, night sweats, that kind of stuff. Like those, those kind of symptoms that the women get during the, during the menopausal transition. And there was... So, like one example is there was a very interesting study where they used nerve blocks to... So, like you, you sort of like inject an anesthetic around nerves in the neck, which decreases some of these symptoms. And in those, uh, who, those who had significant symptoms, and they, 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, uh, body temperature regulation and blood flow and, um, you know, act- 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, um, those symptoms, right? So we know that you can improve them by improving diet quality. You can improve

7. 11:30 – 14:15

   Menopause as a ‘risk amplification period’—especially with metabolic disease

   1. TWDr. Tommy Wood11:30

      them by, um, improving physical activity, right? So yes, hormones play a role, and that is part of that, but we know that other lifestyle factors are, are critically important as well. We also know that this is the, this is the period when the, 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. Um, 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, that, that transitional period. Um, so one example is there was a, a study done in the US where, um-The l- largest cognitive changes seem to be in women who had evidence of metabolic disease. So that's, um, again, we know that metabolic disease is a risk factor for, for dementia and cognitive-

   2. RCDr. Rangan Chatterjee12:24

      Mm

   3. TWDr. Tommy Wood12:24

      ... decline. During the, 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, as a risk amplification period, such that if we, if we think about all the things we've talked about today, um, any r- any ongoing risk factors may have a larger effect as you, as you enter menopause. But that also means that those are things that you have control over. Because by the same token, we know that if you improve f- uh, your diet quality or if you improve your movement, then you can... You'll help control those symptoms, and those symptoms are the, the things that correlate with change in cog- changes in cognition. And the final piece that I think is important is that it is a transitional period. So there was the, uh, the SWAN study in the US 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, uh, once the transition was completed. So if you do experience some cognitive changes during, um, you know, perimenopause, menopause, it's not, um... It, it is, it is a transition. You may... You, you... Like, they may well improve later. And of course, like, in the meantime, if menopausal horm- uh, you know, menopausal hormone therapy or other lifestyle or 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, um, it's not guaranteed that those ch- any changes are gonna be, uh, permanent. Um, and there are several cognitive functions that continue to improve as we get into our 50s, 60s and 70s, and wellbeing as well, in both men and women, um, where, you know, the, the components of, um, crystallized, uh, intelligence, which is a fancy word, way for saying wisdom, um, you know, elements of you're taking in a bigger picture, um, thinking about all the things that we know, putting them in context. They actually improve, um, as does wellbeing. So-

   4. RCDr. Rangan Chatterjee14:13

      A, a different type of cognition.

8. 14:15 – 16:37

   MHT debates and why black-and-white narratives fail women

   1. TWDr. Tommy Wood14:15

      It's a different... Yeah. So, so cognition doesn't get worse as we get 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, in that period. But we've kind of boiled it down to two groups who are like, um, "Hormone's everything, and we need hormonal, uh, hormonal..." um, like, "Menopausal hormone therapy, 'cause if we don't, we're gonna have cognitive changes and experience dementia." And the other group who are saying, "Well, there's no evidence for any of that." Because... And the second group is actually more right, I will say, based on the available data. 'Cause there are studies where they give, um, biogenical hormones to women in the, in the menopausal transition, and they don't see any effect on cognitive function, right? Like the KEEP, like the KEEPS trial, KEEPS-Cog done in Canada. Um, but they can have a massive impact on quality of life and all those other things that I mentioned. So it is incredibly nuanced.

   2. RCDr. Rangan Chatterjee15:20

      Yeah.

   3. TWDr. Tommy Wood15:21

      Um, and I... The, the main thing that I've seen is that there've 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, I just wanna feel better. I want, I want my brain to work better."

   4. RCDr. Rangan Chatterjee15:34

      Yeah.

   5. TWDr. Tommy Wood15:34

      Um, and that's the person that I, that I, I really feel for, and 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, to hormonal therapy, um, if that makes sense for them. But also, there's a lot of power to improve physical health, um, im- you know, start resis- resistance training, which we know can improve, uh, symptoms. You know, start to focus on sleep if you can. Or maybe the, 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.

   6. RCDr. Rangan Chatterjee16:12

      Yeah. Hence the importance of women having better access to well-educated healthcare professionals who know the nuances.

   7. TWDr. Tommy Wood16:20

      Mm.

   8. RCDr. Rangan Chatterjee16:20

      Right? Because that's something probably that hasn't been there. But what... As you said at the start, it's kind of like, well, if you live long enough as a woman, you're gonna go through the menopause. So everyone has hormonal changes-

   9. TWDr. Tommy Wood16:33

      Yeah

   10. RCDr. Rangan Chatterjee16:33

       ... and a hormonal decline, but not everyone gets dementia.

   11. TWDr. Tommy Wood16:37

       Yeah.

9. 16:37 – 17:49

   Exercise through the 3S model: one activity can serve multiple brain needs

   1. RCDr. Rangan Chatterjee16:37

      Right? So it can't just be that that is solely responsible. And could genetics play a role? Could other factors play a role? It is incredibly nuanced, so of course we want more data and more research. Let's talk about exercise.

   2. TWDr. Tommy Wood16:50

      Mm.

   3. RCDr. Rangan Chatterjee16:52

      I know we've spoken before about the importance of exercise for our brains. Perhaps you can give us a, an overview of that. But today I, 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? 'Cause I, 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 gonna help you with your support and recovering from it.

   4. TWDr. Tommy Wood17:28

      Yes. Yeah, so-

   5. RCDr. Rangan Chatterjee17:29

      [laughs] Lots of yeses.

   6. TWDr. Tommy Wood17:31

      Yeah, lots of yeses. So one, one of the, one of the potential downsides of thinking about... And, and, and I've experienced this when trying to explain the, the 3S model to some people, is they, they expect that any given activity only fits in one bucket.

   7. RCDr. Rangan Chatterjee17:49

      Yeah.

10. 17:49 – 23:13

    Three exercise categories and what each does for the brain

    1. TWDr. Tommy Wood17:49

       When of course they don't, right? So, um, I think that there are types of exercise that could absolutely hit three, 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 and the brain, it, it's li- they... it largely comes in three flavors. Um, so, like, aerobic type exerciseUm, resistance training or weightlifting, and then coordinative exercise. And in, in the research they might call it open skill exercise, and I'll, 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, will improve cognitive function if, if you're starting from a, an, a, you know, a low level of initial physical activity, right? So, um, 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. Um, the, the first time we really saw that exercise could improve the, the structure and function of the brain, particularly the hippocampus, which is important for memory and is vulnerable in Alzheimer's disease, was with a brisk walking intervention. Brisk walking 40 minutes, three times a week. So, so, like, any way you start that just, like, starts you moving your body regularly is, is, is great. Um, but aerobic exercise with it... Like, across the scale of intensities, uh, because, right, at the, at the top... You know, the low end you might just have, like, walking. At the top end you might have high intensity interval training, you know, where you do, uh, sprinting on a bike or a treadmill or a rowing machine for some period of time, and then you recover, and you do that... do a few rounds. Those types of exercise, um, seem to be particularly beneficial for the gray matter of the brain, uh, 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, at the higher levels of intensity, we see a greater benefit probably because of the production of lactate, um, which has been, um, sort of derided as a molecule-

    2. RCDr. Rangan Chatterjee20:08

       Mm

    3. TWDr. Tommy Wood20:08

       ... that we want to avoid, that's somehow bad for us, uh, for, for long periods of time. But what we're, what we're seeing increasingly is that it's a very powerful signaling molecule, particularly in the brain. So when you make lactate by, you know... You feel the burn, right? And lactate is part of the buffering system that, that we use when we're doing, you know, anaerobic type exercise or, like, very high intensity exercise. Um, 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, you know, improving function in the brain. So... And, and, and again, uh, when you look at studies where they do high intensity interval training, um, interventions for long periods of time, you see improvements in the structure and funct- structure and function of the hippocampus in particular. Um, so you can see that on a brain scan. Then you also see improvements in memory specifically. So that's, like, the aerobic bucket. Um, then the next bucket is, is resistance training. So a lot of what's different across these different types of exercises is what gets released while we exercise. Um, 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 IGF-1, insulin-like growth factor 1, which is really critical for white matter. So this is something that, uh, we see even in, uh, babies born preterm who are at, um, risk of injury to their white matter and then, uh, associated increased risk of things like cerebral palsy. And IGF-1 is really critical for the white matter. Um, and one reason why babies born preterm have issues with white matter development is because the placenta normally provides the IGF-1 that they use-

    4. RCDr. Rangan Chatterjee22:05

       Mm

    5. TWDr. Tommy Wood22:05

       ... to grow their white matter. Um, but then we see the same thing later in life, where, um, if you do resistance training, you release IGF-1, and the structure and function of the white matter improves. So it's critical, like, throughout in-

    6. RCDr. Rangan Chatterjee22:18

       Mm

    7. TWDr. Tommy Wood22:18

       ... the entire life. That this is a very important molecule for white matter. So the white matter kind of sits i, in the middle of our brains. It makes up about 60% of our bra- of the human brain, and it's responsible for these fast connections between different parts of the brain and the brain and the body. Um, 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, or rapid decision-making. Um, and so... And that, that's, that's because of, uh, the, the, the effects on white matter, we think. Um, 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. Um, white matter changes seem to precede that and, and actually-

    8. RCDr. Rangan Chatterjee23:13

       Mm

11. 23:13 – 26:31

    Why dancing, racket sports, and team games can be ‘all-in-one’ brain training

    1. TWDr. Tommy Wood23:13

       ... predict some of those cognitive changes better. So that's where resistance training becomes really important. Um, and then sort of like the final piece is this coordinative movement. So it's, uh, 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, um, movement component on top seem to have an additional benefit for the brain. Um, 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, uh, running around an obstacle course compared to just running around a, a track.

    2. RCDr. Rangan Chatterjee23:59

       And, and presumably the table tennis, the badminton, the dancing, these are these complex tasks where as well as fitness y- you're doing other things as well. So, so more complex stimuli to the brain?

    3. TWDr. Tommy Wood24:14

       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 changes 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, yeah, we're, um, we're talking dancing, martial arts, ball sports, racket sports, um, any kind of team sport. And what all these things involve is learning complex motor skills-

    4. RCDr. Rangan Chatterjee24:48

       Mm-hmm

    5. TWDr. Tommy Wood24:48

       ... right? Movement skills. But also, often there's a social component. Um, there's also a requirement to respond to the environment, respond to other people, react to the ball being hit at you, um, and strategize, um, quickly and in, in real time, right? So if you're playing tennis, um... I'm a terrible tennis player, so, like, not me playing tennis, but a good person playing tennis, right? You're c- you're, you're trying to not only respond to the, the ball being hit at you and, and moving your own way around the court, but you're trying to manipulate the positioning of your opponent-

    6. RCDr. Rangan Chatterjee25:21

       Mm

    7. TWDr. Tommy Wood25:21

       ... so that you can hit the ball past them, right? And you're doing this at high speed, and so, um, you're challenging multiple senses. And so it's these kinds of complex movements that seem to have an outsized benefit, um, f- f- for the brain. So again, I've, you know, across the things I've mentioned, there could be 12, 20 different things that you could do that, that, that, right, challenge the brain in the same way. So, like, pick one that you enjoy. Um, and if we are thinking about, like, really high-impact or, um, activities that maybe hit all the different, um, nodes of, um, nodes of the 3S model, right? You might think of something like dancing or paddle or pickleball in, in the US, right? There's a social component. There's complex movement. So you're getting physical activity. You're getting cognitive stimulus. You're gonna sleep better afterwards, right?

    8. RCDr. Rangan Chatterjee26:12

       Yeah.

    9. TWDr. Tommy Wood26:12

       All of those things you're doing at the same time. So when, when people do inevitably ask me, like, "Well, what's the one thing I should do?" These kinds of activities are the one thing that, that I would... If you're gonna pick one thing, pick a new sport that requires you to l- use a c- uh, to learn a complex skill and do it in a social setting. You've hit all those different-

    10. RCDr. Rangan Chatterjee26:30

        Everything

    11. TWDr. Tommy Wood26:31

        ... everything in one go.

12. 26:31 – 37:17

    Cognitive reserve thought experiment: Djokovic, retirement, and ‘use it or lose it’ nuance

    1. RCDr. Rangan Chatterjee26:31

       Yeah. 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.

    2. TWDr. Tommy Wood26:37

       Yeah.

    3. RCDr. Rangan Chatterjee26:38

       Um, last summer, my son broke his wrist at the end of, end of the summer holidays and, um, had to wear a cast. And one of the things we like to do, particularly in the summer, we have this outdoor table tennis table, and we basically decided, with a bit of cajoling from me-

    4. TWDr. Tommy Wood26:58

       [laughs]

    5. RCDr. Rangan Chatterjee26:58

       ... that we were gonna play left-handed table tennis-

    6. TWDr. Tommy Wood27:00

       Uh-huh

    7. RCDr. Rangan Chatterjee27:00

       ... while his cast was healing.

    8. TWDr. Tommy Wood27:03

       Yeah.

    9. RCDr. Rangan Chatterjee27:03

       I'm not kidding you. Like, we started off, the first time was, oh, man, this is... And w- you know, we're decent players with our right hands.

    10. TWDr. Tommy Wood27:10

        Yeah.

    11. RCDr. Rangan Chatterjee27:11

        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.

    12. TWDr. Tommy Wood27:22

        Ah.

    13. RCDr. Rangan Chatterjee27:22

        But he's a decent player, but-

    14. TWDr. Tommy Wood27:23

        Yeah

    15. RCDr. Rangan Chatterjee27:24

        ... I just thought, wow. And it, and I think that speaks to this broader point, doesn't it, about how quickly our brain can adapt and respond? And I've also read some stuff that perhaps learning it with a, with the weaker hand then improves your ability with the stronger hand because different regions of the brain are connected.

    16. TWDr. Tommy Wood27:43

        Yeah.

    17. RCDr. Rangan Chatterjee27:43

        So that was one thing I thought about. The second thing I thought about was in relation to this, I know we've not spoken today about headroom and cognitive reserve. I know we've spoken about that before, and, and obviously you write a lot about it i- in, in the new book. I thought about Novak Djokovic.

    18. TWDr. Tommy Wood28:03

        Oh, yeah.

    19. RCDr. Rangan Chatterjee28:03

        Okay? So he's still getting to Grand Slam finals.

    20. TWDr. Tommy Wood28:08

        Yeah.

    21. RCDr. Rangan Chatterjee28:08

        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? So, and, and also he's, he pays attention to detail. Like, he, he leaves no stone unturned in his desire to get better, whether that's eye training, um, you know, juggling before he might go out onto the court, um, you know, mindsets, nutrition, movement, recovery, all these things that you probably see with your Formula One drivers, right?

    22. TWDr. Tommy Wood28:49

        Yeah.

    23. RCDr. Rangan Chatterjee28:49

        So let's say at 40, he just stopped. Hypothetical scenario.

    24. TWDr. Tommy Wood28:55

        Yeah.

    25. RCDr. Rangan Chatterjee28:57

        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-

    26. TWDr. Tommy Wood29:06

        Yeah

    27. RCDr. Rangan Chatterjee29:07

        ... and headroom. If the day after he retired, he... I'm, I'm almost certain he wouldn't do this.

    28. TWDr. Tommy Wood29:16

        [laughs]

    29. RCDr. Rangan Chatterjee29:16

        But let's say the day after he retired, I, I use the word retire 'cause this is kind of what happens to people at 65, right? He stopped doing anything.

    30. TWDr. Tommy Wood29:26

        Yeah.
13. 37:17 – 41:41

    A realistic weekly exercise plan: movement funnel, minimum effective dose, and coordination

    1. RCDr. Rangan Chatterjee37:17

       Just coming back to those three types of exercise.

    2. TWDr. Tommy Wood37:19

       Mm.

    3. RCDr. Rangan Chatterjee37:20

       I just wanna... As you said, the practical take-home is move, right?

    4. TWDr. Tommy Wood37:26

       Yeah. [laughs]

    5. RCDr. Rangan Chatterjee37:26

       Um, you know, and as you said, I think you said dementia risk goes down up to about 8,000 to 12,000 steps.

    6. TWDr. Tommy Wood37:32

       Yeah.

    7. RCDr. Rangan Chatterjee37:32

       Doesn't mean you can't do more than that-

    8. TWDr. Tommy Wood37:33

       No, yeah, yeah

    9. RCDr. Rangan Chatterjee37:33

       ... but you may not get the benefits in the same way.

    10. TWDr. Tommy Wood37:37

        Or you just, you don't see additional benefit.

    11. RCDr. Rangan Chatterjee37:39

        You don't see additional benefit.

    12. TWDr. Tommy Wood37:39

        You'll still get that benefit. Yeah, yeah, yeah.

    13. RCDr. Rangan Chatterjee37:41

        When it comes to lactate, and I think you spoke about in the context of high-intensity movement-

    14. TWDr. Tommy Wood37:46

        Mm-hmm

    15. RCDr. Rangan Chatterjee37:48

        ... lactate has particular benefits for the brain.

    16. TWDr. Tommy Wood37:50

        Yeah.

    17. RCDr. Rangan Chatterjee37:51

        That doesn't mean that people shouldn't do low-intensity training because it's-

    18. TWDr. Tommy Wood37:54

        No

    19. RCDr. Rangan Chatterjee37:54

        ... 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 j- want, I wanna 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?

    20. TWDr. Tommy Wood38:19

        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. Um, 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 occa- 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-

    21. RCDr. Rangan Chatterjee38:59

        Mm

    22. TWDr. Tommy Wood38:59

        ... as much as possible? Like, break up periods of sitting, take the stairs, walk for 20 or 30 minutes a day. I have, in, 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 sedentary during the day.

    23. RCDr. Rangan Chatterjee39:13

        Mm.

    24. TWDr. Tommy Wood39:13

        However you do it, stand up, walk around, take the stairs, anything. Um, then the next level is propel, which is basically just do some low-level movement or whatever you can. Um, 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 s- 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, uh, a, a little bit or something. You just sort of, like, layer on little bits of intensity because we know that that, that has additional benefit. And then once or twice a week, I'd go and lift, do some kind of resistance training. Um, and that's, that's what we think the, like, the minimum effective dose to build strength, muscle mass, and then also, um, improve, uh, brain health. Or at least o- you know, once a week-

    25. RCDr. Rangan Chatterjee40:06

        Mm

    26. TWDr. Tommy Wood40:06

        ... probably. Your very basic, uh, six or eight exercises that cover the whole body, three sets of 8 to 12 reps. Like, the, the basics. Like, maybe, maybe the best is twice a week if you can. Um, but then in reality, if you're gonna try and tick multiple boxes in, in just like a, a normal person's schedule, I would make some of my aerobic type exercise something that's more coordinative, 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-

    27. RCDr. Rangan Chatterjee40:45

        Mm

    28. TWDr. Tommy Wood40:45

        ... you know, a additional benefit and you, you know, all the other things that we've talked about. Like, th- that's it.

    29. RCDr. Rangan Chatterjee40:50

        Super helpful, and that's one of the things, Tommy, I also, I, 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, and see where the most, where most people are at and-

    30. TWDr. Tommy Wood41:03

        Yeah
14. 41:41 – 50:54

    Author’s wrap-up: building long-term foundations, travel stress, and hope for prevention

    1. RCDr. Rangan Chatterjee41:41

       Right? Um, Tommy, I could talk to you for hours and, um, there's just... Of course, because you've written such a thorough book, we, we, 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. Um, I, I love the title, I love the subtitle. The Stimulated Mind: Future-Proof Your Brain From Dementia and Stay Sharp at Any Age. On a personal level, how has it been for you doing all these interviews about your book?

    2. TWDr. Tommy Wood42:11

       [laughs]

    3. RCDr. Rangan Chatterjee42:11

       You're traveling a lot, you're doing a lot of podcasts. That takes its toll.

    4. TWDr. Tommy Wood42:14

       Yeah. It's, um... Well, m- maybe before I get, before I get to that part, uh, I just w- wanted to say that this book exists because of you, and I wanted to say thank you for that. So for, for two main reasons. Um, the, the first being that you were the first person that I think I really spoke to about wanting to write a book, right? Several years ago, right, we, we talked about this.

    5. RCDr. Rangan Chatterjee42:38

       Yeah.

    6. TWDr. Tommy Wood42:38

       Um, and I had various ideas, and those ideas have, have shifted over time, but the, you were sort of the first person to kind of encourage me to, to do that, and I really appreciated that. Um, and then, um-One of the, uh, previous episodes that we did, I think it was the second time I was on the, I was on the podcast, um, there was somebody, uh, she used to work at Ebury, which is a Penguin imprint. She's called Anya Hayes. She now works for Hay House. But she sent me an email and was like, "I listened to your, uh, episode with Rangan. I think you should write a book." Um, 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, that kind of brought us to, to here today. So, like, thank you. Like, the, th- this exists, um, largely because of you and, and I, and I, and I, I wanted to, like, really, you know, say thanks for that.

    7. RCDr. Rangan Chatterjee43:24

       Oh, well, I really appreciate that, Tommy, and, and it's at... my absolute pleasure.

    8. TWDr. Tommy Wood43:27

       [laughs]

    9. RCDr. Rangan Chatterjee43:27

       And, uh, I take no credit for how great the book is.

    10. TWDr. Tommy Wood43:30

        [laughs]

    11. RCDr. Rangan Chatterjee43:31

        Um, but thank you.

    12. TWDr. Tommy Wood43:32

        Um, so, so yeah, then r- like, writing the book, I, I loved it. It's, it's hard. It's, 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, which was really important to me. Um, like, I loved it. But the hard part is then you have to go out and you have to tell people about it, right? Um, and you, you obviously have done a lot more of this than, than I have. Um, but yeah, I... In general, I, I quite like, uh, being at home. I like, uh, working with the people that I have, uh, in my lab. I like spending time with my wife and my dogs. Um, 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. Um, you know, be on podcasts that I've listened to for more than a decade is, is an incredible experience. But you're right. There's jet lag, travel. There's, there's stress. Not, not, not being able to do the things that you'd normally do-

    13. RCDr. Rangan Chatterjee44:34

        Mm

    14. TWDr. Tommy Wood44:34

        ... to kind of like look after your, look after your health. Um, it's, it's been a bit of a... It's definitely been a bit of a rollercoaster and, and whirlwind, and, like, I'm incredibly grateful for all of it. But you're right, like, [laughs] there's only so much of this that, that one person can, can do because it does, it, it takes a lot of effort.

    15. RCDr. Rangan Chatterjee44:49

        A- and if we look at that, I just had a thought there. If we look at that through your three S 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?

    16. TWDr. Tommy Wood45:02

        Yeah.

    17. RCDr. Rangan Chatterjee45:02

        So we could say let's forget about the writing of the book just for a moment. Let's say all this travel and, uh, being asked questions about... You know, it's s- such a thorough book. People could ask you something from anywhere.

    18. TWDr. Tommy Wood45:14

        Yeah.

    19. RCDr. Rangan Chatterjee45:14

        And you've got to answer questions-

    20. TWDr. Tommy Wood45:16

        Oh

    21. RCDr. Rangan Chatterjee45:16

        ... 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, um, make sure the supply is good.

    22. TWDr. Tommy Wood45:28

        Yeah.

    23. RCDr. Rangan Chatterjee45:29

        So you'll try and eat well. We haven't spoken about blood flow restriction today.

    24. TWDr. Tommy Wood45:33

        [laughs]

    25. RCDr. Rangan Chatterjee45:33

        But we're gonna do that next time, for sure, right? So you'll be doing things about exercise a- and making sure that there's enough flow to the brain.

    26. TWDr. Tommy Wood45:41

        Yeah.

    27. RCDr. Rangan Chatterjee45:41

        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, and your, and 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? Do you know what I mean?

    28. TWDr. Tommy Wood46:07

        Yeah, absolutely, and that is, that, that is, uh, definitely in the plan. Like, you know, my wife and I, we've sort of sat down, and there's been a, a, a big burden on her to, like, um... There's, there's more that she has to do when I'm not at home, right? So, um, it's, it, it's been a, a burden on, on both of us, and then figure out, like, when's this hopefully gonna wind down? What are we gonna do to kind of take some time to ourselves and spend time together?

    29. RCDr. Rangan Chatterjee46:30

        Yeah.

    30. TWDr. Tommy Wood46:30

        So, like, that, that's a big part of it. Um, but I, I think that your, your point is really i- really important because all of these things integrate over incredibly long time periods, right? We have decades over which that we can, um, influence our, 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.

Episode duration: 50:55