Good Life Project - How to Avoid Cognitive Decline & Dementia (starting in your 40s) | Dr. Tommy Wood

Episode Date: August 20, 2026

Your brain does not have to decline with age. Recent research reveals that for most people, staving off cognitive decline or dementia is more about lifestyle, especially in your 30s to 50s, than age or genetics. And, amazingly, retirement might be the single biggest danger zone for your brain health.Neuroscientist Dr. Tommy Wood has spent his career studying what actually predicts a declining brain, and the answer has almost nothing to do with age. It's what happens the day you stop being challenged, especially the day you retire. This week: why the smartest, most accomplished people you know may be the ones most at risk, and the two-part check you can run at your next doctor's visit that sets the stage for the next fifty years.What you'll explore:Why age-specific dementia rates have quietly been falling for decades, even as headlines warn of a coming epidemicThe real difference between forgetting a name (a retrieval problem) and never actually experiencing it in the first place (an encoding problem), and why only one of those predicts dementiaTommy's 3S model: stimulus, supply, and support, the framework he uses to make sense of everything that keeps a brain sharpThe truth about brain games, and what really works to keep your brain primed with ageWhy the most educated, highest-achieving people often face the steepest cognitive drop right after they stop workingThe exact numbers to get checked at your next doctor's visit if you're in your 40s or 50sIf you're standing at the edge of any major life transition, or supporting a parent who is, this conversation will change how you think about what actually protects your mind.You can find Tommy at: Website | Instagram | Episode TranscriptNext week, we're sitting down with Dr. Jessica Shepherd, alongside guest host Karen Walrond, to talk about why so much of what we've been told about menopause is either outdated or flat wrong, and what personalized care for this stage of life can actually look like. Be sure to follow Good Life Project wherever you get your podcasts so you don't miss any upcoming episodes!Check out our sponsors and resources: Visit Our Sponsor Page Hosted on Acast. See acast.com/privacy for more information.

For decades, we have been told that a sharp, quick mind is a young person's game, and everything after is kind of slow decline. Today's guest says, that's mostly a story that we've internalized, not a biological fact. And there's one major life transition that most of us spend our whole lives looking forward to, that may quietly be one of the most dangerous things you can do to your brain. If you want to know exactly what that is and why, and the numbers to check at your next doctor's is it that could really change a whole trajectory of your brain health, stick around. In this conversation, you'll discover why age-specific dementia rates have actually been

falling for decades, even as headlines warn of a coming epidemic. We'll talk about the real difference between forgetting a name and never truly encoding it in the first place and why one of those only predicts decline and even dementia. Why retirement, especially early retirement, can quietly accelerate cognitive decline in even the sharpest most accomplished people. We'll explore the three-part framework that ties together nearly everything we know about a resilient brain and the specific blood work to request and things to do this year that sets this stage for the next 50. Our guide is neuroscientist, performance consultant to Olympic athletes and Formula One drivers, and author of The Stimulated Mind, Dr. Tommy Wood.

I'm Jonathan Fields, and this is Good Life Project. We'll jump right in after this short break. One of the things that I really want to start with is sort of on a med level here is a question. And the question is whether cognitive decline, our ability to think deeply, to think clearly, to process complicated things, and even remember things, whether a decline in that is inevitable as we age. because I think that's the story that so many of us have been told and never really kick the tires. Absolutely. And it even could get more interesting than that because our cognitive function may purposefully change over time, and that may not even be a bad thing. So one example of that before we jump into the decline is that when we look at our different cognitive functions, and there are several that we can sort of measure and we think we can maybe isolate,

as neuroscientists, where there's one group of cognitive functions that we call crystallized intelligence, which is basically a fancy neuroscience word for wisdom. And this is our ability to remember facts about the world, integrate them together, have some bigger picture and make decisions, maybe not decisions that require very rapid decision-making, but sort of these like bigger picture questions and things we might want to do. And that actually improves. Our crystallized intelligence improves into our 60s and 70s and maybe even beyond. Even while on average, we expect other functions to decline, things like reaction time or

working memory or how quickly we can process information. So some of it actually is just a shift in how our brains work as we experience more of the world over time. And that's not a bad thing. That's our brains working as expected. But when we think about this idea that our brains are destined to decline with age, this is something that has sort of been baked into society over the last 100 plus years. And I argue that maybe it started around the beginning of the 20th century

when they were trying to formalize the idea of retirement. Before then, people didn't really retire. They couldn't afford to. There weren't such thing as pensions, where you had to work until you. you died. And there were people like Sir William Osler, who was a Canadian physician, helped found Johns Hopkins Hospital, who helped to popularize the idea of retirement. And one of the ways he did that was by telling people, you know what, by the time you're 60, you're essentially useless, and we should just put you out to pasture. That's paraphrasing, but it's essentially

what he was known to have said publicly. And of course, back then, you know, the average 50-year-old probably wasn't in as good health as they are today. But we've essentially internalized this idea that at some point, you know, in our 60s, perhaps, we expect this decline and we expect to no longer be useful. And we have data, you know, even that's like 50 or 60 years old, that disproves this. So one example is the Seattle Longitudinal Study that was run at the University of Washington, where I now work by Warner Shai. and for the first time, they took the same people and they measured their cognitive function over multiple decades.

They brought them back every seven years, and they measured the same person with the same tests, and they saw how their function changed over time. And for most people, their cognitive function did not change from their 50s to their 70s and beyond. And this was starting in the 1950s, right? This is quite a long time ago now. And this is not what we expect. expect those people to have declined. And those data are actually used to raise the retirement age in the US in the 1980s. And whether or not you're glad about that, you know, that's a more of a

philosophical thing. But we've known for a long time that the average expectation should be that you maintain cognitive function from your 50s into your 80s. And yes, some people will potentially lose some function. And there are a number of modifiable factors that can alter that trajectory. But fundamentally, we have a lot of data that shows that actually the expectation should be that we maintain function. And it's not unusual for that to happen. And now we understand a lot more about the things that we might be able to do in order to achieve that. I mean, it's fascinating also that that data started in the 1950s, because you look at that and you're like, well, you know, in the 75-year-year span since then, the life expectancy has certainly improved medicine as

improved in so many different ways, but also what people tend to learn and know about how to live a quote, healthier life has, you know, improved dramatically also. So, you know, the typical person lives very differently now that it did in the 50s. And you're saying that even with that, data started in the 50s still tracks to show that this is still true. Yeah, absolutely. And then sort of alongside that, like you're saying, things have improved a lot in terms of, what we know about treating, preventing chronic disease, what we know about what it means to live a healthier lifestyle. And with that, we are actually seeing changes in dementia diagnoses

that don't get the headlines that they should. So what you'll hear most of the time is that dementia burden is increasing, that it's going to double or triple in the next two or three decades. It's going to be the disease that bankrupts, Medicare, Medicaid. like we've heard versions of these things. And that's potentially true if we sort of continue on the same trajectory. But it's largely because we've gotten so good at preventing other diseases that we're living an increasingly long time. And dementia is therefore sort of coming, sort of rising up in terms of potential causes of death.

But when you look at the data another way, something called. age-specific incidence of dementia is decreasing. And age-specific incidence means that at a given age, how likely are you to be diagnosed with dementia? And that has been dropping for the past several decades. So at 70 years old now, you are less likely to be diagnosed with dementia than any other time previously in history. And nobody tells us that. And one of the reasons for that, one of the reasons, primary reasons that's thought to be the case, is because we've gotten so good at treating and preventing heart disease, which is a major risk factor for dementia. But there are other things that have shifted too. So smoking has obviously decreased. That's been a big part of

cardiovascular risk reduction. But also access to education and the work environment, particularly for women, has improved a lot over the past 40, 50 years. It was only really in the 70s that that that started to shift and become much more equitable in the US, for example. And we know that education and the type of work that you do is also an important risk factor for dementia. So multiple things have improved, as you've said, over the last five, six decades. And that's actually being borne out in the data. Unfortunately, we just don't get told that.

We sort of get told the doom and gloom, which makes us think that we're destined to experience this when actually a lot of, you know, a lot of things are suggesting that it might actually be getting better as we. get better at sort of addressing our personal and population health. That's so interesting. Knowing that that's a big part of the story that's really not being told, kind of changes of the way that you look at it. I want to choose out a distinction that you're making here, though,

because I open the conversation asking you about sort of generically cognitive decline. You talked about this thing called crystallized intelligence. I've also heard the complement of that fluid intelligence. And then you're moving us into the domain. of dementia. Yeah. Talk to me about the span here. Like, what is this or like the, like, how do we go from completely, like, high functioning?

You know, our brain is, you know, firing on all cylinders to cognitive decline to dementia. I'll start at the end there. It's just sort of like dementia is the end state. And that, because, and the reason why it's useful to talk about that is because this is what people really fear. Yeah, for sure. I think, right? dementia being a clinical diagnosis, you know, made by a doctor after a series of tests,

where somebody has lost enough cognitive function that they're no longer able to look after themselves on a day-to-day basis. That's essentially what might cause a diagnosis of dementia. And there are multiple types of dementia or causes of dementia. The most common is Alzheimer's disease, which people almost certainly have heard of, which makes up 60 to 80% of cases of dementia. And one of the reasons I was making the case, you're giving the details about education and workforce for women is because two-thirds of the burden of Alzheimer's disease

affects women compared to men. The next most common cause of dementia is vascular dementia, which essentially changes in blood vessels in the brain or changes in blood supply to the brain that then affects cognitive function. And actually there's a huge amount of overlap between vascular dementia and Alzheimer's disease. And often in most people, they actually occur together, that between them making up 70 to 90% of the cases of dementia. And these are the case of dementia in particular that we now think are potentially preventable if we do, you know,

change some aspects about lifestyle and the environment that could support. So that's the more vascular oriented. Yeah. So vascular oriented or more directly linked to. the environment and lifestyle, whereas other cases of dementia are maybe less so. There's still a role to play there, but it's more strongly linked in vascular dementia and Alzheimer's disease. But you're absolutely right that there's some trajectory there. You don't suddenly experience dementia. It's thought to be, so the changes in brain function, brain health, cognitive function,

and then essentially the sort of trajectory downwards in terms of cognitive function that might end up with dementia happens over decades. And it really seems like midlife is the period of time when risk becomes amplified. So in our sort of 30s to 50s is where you're really sort of setting the scene for what's going to happen to your brain in the future. And this is changes in physical health. This is how we sleep. This is how we move physical activity, smoking,

some of these other things we've touched upon a little bit already. It essentially may take decades for these things to compound and start to affect the brain. And then maybe within 10, 20 years, you might start to experience some changes. The first stage of this progression is now something called subjective cognitive cognitive decline, you might notice some changes or somebody who knows you very well might notice some changes.

What would be examples of that? It might be that people are noticing some changes in your personality, some things that it might be changes in memory. We often think about memory, but it isn't always memory. Something that is frequently affected in Alzheimer's disease, for example, and many, many dementias, is executive functions. So is being able to kind of make decisions and plan. So there have been some recent studies that show that maybe a decade or at least several years before somebody gets a diagnosis of dementia, they've been gotten much worse at managing their personal finances. For example, they're not able to plan, they're not able to budget, they're not keeping an eye of what's coming in and what's going out. Those kind of like complex day-to-day processes that we do, you might notice in a loved one or potentially in yourself that mistakes have been.

made or you've been able to keep track of things or and and that that's kind of that might be the first thing that that could be noticed um in the very early stages it's thought that those changes are potentially reversible so if we can identify risk factors if we can i you know identify potential interventions again related to lifestyle treating cardiovascular disease risk factors treating things like diabetes or high blood pressure we might be able to reverse a lot of those changes. That's probably going to get harder and harder as you go down that trajectory. But it's really, so it's really in that early period or period before you even notice something that you can kind of set the stage for what happens later. I will say, though, that there are now

lots of studies, your big, randomized controlled trials that show that people in their 60s or 70s, if we change their diet and we give them some, you know, improve their physical activity and we address their cardiovascular risk factors, you can see significant. improvements in cognitive function even sort of in older adults. So even though I'm talking about midlife as this important period, which it is, you can still see significant benefit and changes, you know, even after that. And we'll be right back after a word from our sponsors. One of the things that's coming up for me is I'm sure we have people joining us and

they're kind of nodding along and maybe they're questioning this about the moment they're in their lives or maybe they have parents. and they're questioning about them or they're, like, supporting parents. But, you know, they're also probably asking themselves, okay, so, yeah, the classic guy, where did I put my keys? Or, like, what's the name of that person again? Or, like, those sort of, like, everyday things. How do you start to tease out?

Are these early signs of something that I should be really addressing to the extent that I can address it? Or am I just stressed out of my mind? Am I just overworked and overtired and eating terribly? Like, how do you start to make these distinctions? Or is it just a yes-end thing at all? A little bit, the answer is like, well, yes, yes to both. But there are some important distinctions that can be made.

So when you're thinking about what happens in the brain in an individual with Alzheimer's disease, for example, what changes, or one of the things that seems to change, is, particularly as we're talking about memory, is the encoding of memories. And so there are three main stages of memories. It could get a lot more complicated than that, but just for like our purposes,

there's three main stages. One is encoding. You have experienced something, you've decided, this is something you're going to remember. The brain starts to make changes in order to remember this thing. Then there's consolidation. This is the process of actually building, you know, kind of building that into the network such that this is something you remember in the future. A lot of that happens during sleep. And then there's retrieval, you know, actually accessing that

memory when you want to access it. When, you know, in that scenario you described, I just can't, who's this like, I've met this guy like 10 times. I just can't, can't remember his name. That's a retrieval issue. And for most people, retrieval issues are generally related to what you described. They're stressed. They're sleep deprived. They were distracted when they met this guy last time and they weren't really paying attention. And so that tends to be reversible. If you can address some of those things, you can, we know you're likely to be able to recover a lot of that. And like some of it's just like situational. You're also trying to remember it, but you're also trying to think about this other thing that you were doing and you're worried about

where you've got to pick up the kids later and what am I going to have for dinner, right? So like, most of this I think is relatively normal. And a lot of these more episodic type memories, we call them, just like, you only remember this guy because you see him in this place. And if you see him out of context, your brain doesn't really have the infrastructure to, right? And so like, this is entirely normal. When people experience dementia, more often it's an encumely. coding issue, right? That memory never gets placed or tagged for, or, you know, that experience never gets tagged to be saved as a memory. So the individual never remembers that there's a thing that they're supposed to remember. They, right, it's as if it never happened. So there is a

distinction there in terms of the experience that you have. However, if you are somebody who, for several decades of your life is sleep deprived, stressed, distracted, you know, eating poorly. And actually, we know that if you force people to eat like a large amount of a Western-style diet in a lab study, like their memory gets worse, you know, within a week. And so if that's you for long periods of time, we know those increase your risk of dementia. So in the short term, it's not necessarily something to worry about. It could be it's a normal part of the modern life experience. But if those things are never addressed and they happen for decades at a time, we do know they then increase your risk of later dementia. Yeah, that makes sense to me.

As you're describing those three different stages also, what popped into my mind was a conversation I had not too long ago with somebody who is one of these people who would walk into a room and he would meet 100 people. And at the end of it, he could tell you the name of every single person in the room. And I said, what's going on there? And he's like, he's like, what most people don't realize is with things like that, it's not that you can't retrieve it, as you were just describing, you never encoded it. Yes, absolutely. And that's not necessarily a bad thing, right? There's, if it's really important to you to remember the 100 people in this room and you focus on each of them and you focus on some features of them and you, and you like tag that to the name and you're having

this conversation and you're like making eye contacts and you're really kind of internalizing it, you will encode that information, but you need to tell your brain that it's important in the first place. And it may not be. It may not be important to you to remember those hundred people. And so unless you're really focusing on this and there are aspects of memory that are critical to encode that memory in the first place, like importance and distinctiveness and like, how do you tell the brain that this is something you actually want to remember by engaging with that information and giving it a reason, you know, and other tags to kind of remember it, right? But if you're not doing that, don't expect to remember it. And that's normal.

Like the standard procedure is for your brain to forget. Actually, the standard procedure is for you to never even experience it in the first place. Like most of your brain's computing power is filtering stuff out so that you only get what it thinks is important. So you can change that, but it requires you to, you know, really engage in the process of making. that memory. Yeah. And what you said is so important. I want to repeat it again, make sure. So most of what your brain is doing for, you know, throughout the day is filtering out a massive number of stimuli or input so that you actually can focus on the few things that genuinely matter to you. So we have things

coming on us all day, every day. But if our brain literally tried to make all of them important, encode all of them, put them into our, we'd probably couldn't function. Yeah. So there's a really nice paper that there's related to this. It was called the unbearable slowness of being. But basically, I love the day. Yeah, I know. And it also just kind of describes, where we think of our brains as these amazing supercomputers, which they are. But it describes how slow human thought actually is. Like when you really boil it down, humans do not think that quickly. And so like they put a number on it, 10 bits per second. So like a bit is like a single one or a zero, right? So you can process 10 ones on zeros a second, which actually when you're

thinking about all the stuff that you're exposed to isn't very much. And so they liken the amount of information that you're, that comes into your brain versus the amount of information that you can actually physically be cognizant of and process is the same as the amount one huge, can drink relative to the amount of water coming through the Hoover Dam. Right. So, like, what your brain is doing is figuring out which water you should drink while the rest of the water that comes to the Hoover Dam is being kind of let to run past you. And so, like, that's the kind of scales that we're talking about. Yeah, that makes no much sense.

And I would imagine now also with all of us tethered to our devices and billions or trillions of dollars. being spent on algorithms that try and tell your brain, oh, this is important. It's even harder these days. Yeah. Yeah, yeah. Especially like, even beyond that, right? So if we go to an app or something and we're focusing on one thing, that is what, like, one thing. Obviously, your attention is being captured.

You're being told what is important. But beyond, but it's not just that. Probably more insidious is the fact that while you're doing that, somebody's texting you, Slack and teams are popping up, and, you know, you're trying to watch Netflix at the same time. So, like, you can't even focus on this one thing that's trying to capture attention because, like, everything's trying to distract you. And then that is the exact opposite of what is required in order to, you know, make, make memories in the first place, let alone remember them later. Yeah, that makes so much sense. You argue also, I think this is really

interesting that, you know, if we're looking at sort of like moments or windows or occasions in our life that many of us will experience, better danger zones for cognitive decline or an acceleration towards potential dementia, retirement is one of the clearest danger zones. Take me into this. Yeah. So I think I've previously said that retirement was the worst idea the brain ever experienced. And I'll preface this by saying that, you know, if you had a long career, and you're ready for a break, I'm not saying you shouldn't enjoy your well-earned retirement.

That's not what I mean. It's that when you look at lots of big population studies, the time when cognitive decline tends to accelerate is around the period of retirement, particularly dangerous for those who retire early, even after you account for medical conditions or something else that might be. cause you to retire early. And the reason this is thought to be the case is that the primary driver

of your cognitive function is the way your brain engages with the world. It's the skills you learn, the people you meet, the problems you solve. And most of that occurs during work. And so if we retire and we don't replace those cognitive inputs with something else that stimulates our brains in a similar way, we're removing this critical input that helps to maintain function. It's very, very similar to a professional athlete retires and then just never works out again. And you can very rapidly see a decline in their physical function, right? Because they're no longer providing that physical stimulus. And the brain is essentially the same.

So this is just something that we need to know about. and interestingly, it's difficult to like really tease this out from the data, all of its observational, but there's some suggestion that those who maybe had the highest levels of education and the most demanding jobs are at the greatest risk during this period because their brains are just used to all these inputs. They're used to solving all these problems, going to all these meetings, like doing all this complex work, that their brain is kind of dependent on it in order to maintain its function. So then you just have to make sure you're doing something else during this period of retirement. So are you learning new sports or new languages or a musical instrument?

Are you volunteering? Like, how are you continuing to show your brain that it's worth sticking around? Because that's essentially the signal that's going to keep it there. Yeah. So it's not really, it's not the fact of retirement that triggers a slow decline. It's the fact that you've been doing hard things and struggling and probably. solving and dealing with all sorts of things moving at you for decades as you work. And then all of a sudden, there's the day where you see the plaque and the pen and you walk out of the office. And, you know,

you walk into this next season and all of a sudden, all that isn't there just by default. And so all of the things that kept your brain in prime form aren't there. So it sounds like then what you're saying is, if that, in fact, is what retirement looks like for you, then it's on us to figure out how do we then invite new things into our experience of this season to continue to bring novelty and difficulty and challenge to the brain? Because that's, why is that so important too? That's absolutely right. And I think some of this is related to what Arthur Seabrooks is called The Stryver's Curse, which is that, right, when you've been so successfully, you've achieved so much and then, right, through your work and then you lose that, all of a sudden there's

this like, well, what's the point? Like, there's like the, the meaning is lost, purpose is lost. And so some of it is like regaining or finding a new, new ways to find meaning in what you do, which is like critically important for humans. But fundamentally, the majority of the tissues in the body and organs in the body, their function is driven by the demands placed on them. And the physical function in people who exercise or don't exercise, but just in people who move their bodies,

I think is the best example because those processes are essentially identical in the brain. So if you want to get stronger or you want to get fitter, the most important thing to do is exercise or movement that kind of drives that adaptation. You want to get bigger biceps. You need to do bicep curls. You want to be a better marathon runner. You have to go and run. And this is what drives the adaptation.

What maintains the function of the cells. It drives a whole bunch of processes that we think of as anti-aging, right? There are some biochemical processes that we call aging and exercise in the muscle tissue is the main thing that prevents or reverses those changes. And it's really the building and maintenance of function. that is driven by how we use our muscles or how we use our bodies. And the brain is essentially the same. And you can see some of these exact same processes. So you stimulate a network in the brain that's important for focus and attention

because you're actually like truly focusing on something. You activate all these same pathways, right? You upregulate the performance of the mitochondria and like energy production. And you start to clean up the cells from like junky proteins that can accumulate over time. because of the stimulus you're putting on those cells and those networks. And it's the same for pretty much any tissue you can think of in the body. It's like the same for your bones. It's the same for your immune system, right?

Your immune system, if it's challenged with a vaccine or an infection, right? It usually gets better at dealing with it next time. And so that's really it, is that the function of our cells is primarily driven by the challenges they face or the stimuli they get. And yes, we can improve our ability to respond to those stimuli, just like if you're an athlete, you want to make sure that you're getting plenty of nutrients and enough protein and enough sleep, right, because that's when you adapt and you recover to the training you did. But the training is fundamentally a critical part of building function. And so this is just a fundamental aspect of our biology.

We want a tissue to function better. We need to apply a stimulus to it. Yeah, it's funny. I think, you know, it makes total sense when you think about the muscles in your body. I've got to work out. If I want to stay strong, if I want to be able to do all these different things. We don't make that automatic leap to our brains, though. We're like, oh, the brain isn't a quote muscle, right?

So it's got to be different. And yet what you're saying is not so much. Yeah, they're sort of, you know, biochemically or physiologically, very similar things are happening. You can't see it, which is why I usually talk about. that analogy to physical function or strength or muscles because that's something we can see we can we can we understand it but actually when you look at studies that um kind of track what happens after you apply a stimulus to your brain you see just the same things happening as you see in in the muscle tissue um you can build more brain structure you can make it function better right so so like muscle structure is like muscle size and then muscle function is muscle strength right you can get parallel improvements in the brain that we can actually sort of measure in various ways. It's just harder for us to see because it's kind of in there. We're not all walking around with scans where people can just look at it and see what's happening inside of us.

And we'll be right back after a word from our sponsors. One of the things that became popular, I feel like I don't hear as much of it now, is this notion of brain games. And it started out in a more analog way of well, let's do crossword puzzles. and SuduKones, things like that, and then it became digitalized and apps and all these different things. Are things like that enough to make a meaningful difference? So the quick answer is no. It doesn't mean that they're bad. And when you look at the things that people do with their brains as they get older and their later risk of dementia,

often there will be a case of, well, how many different skills, activities, hobbies, things do you engage in? And it seems that those who, you know, regularly do three or four things that kind of challenge their brains tend to, and that can be, come, you know, from physical movement, dancing, languages, volunteering, like that kind of stuff. But then there's also reading, crosswords, going to lectures, things like that. So crosswords kind of, and Sudoku and Wordle or whatever, They kind of fit into there as, yes, it could be parts of the picture. And some of the studies have kind of shown that. But it's never enough on its own.

And the reason for that is, if you think about how you're using your brain, Gloria Mark is a, she's an occupational psychologist. Everybody, if you haven't read her book, read her book, attention span. It's fantastic. And she has this quadrant in terms of focus and challenge, right? So, and so like there's two levels of focus and two levels of challenge. So things like Sudoku and Crosswords, you're focused, but you're not challenged. Right.

So it feels good. You're kind of doing something you're good at. You get a little bump of, oh, yeah, I achieve something. But the type of activity that really shapes the brain is where you're both focused and challenged. And that's what happens during complex skill learning, complex problem solving. And that's, it can be hard to do for extended periods of time. maybe you can only do it for 30 or 60 minutes time, right? You can't go, it's kind of like, you know,

you can't go and lift your heaviest squats in the gym all day every day, right? You need focused periods of training and then you need to rest and recover and adapt afterwards. So it can be part of, so like Crosswood and Sado can be part of the picture, but you also want something that's really kind of stretching complex, complex skills. So challenge is to really be part of it. It's not just focused challenge. Exactly. So challenge is really important. And so one, like, small part, like sort of part of this picture, because you mentioned brain games, is there, there is one type of brain training that does have some good evidence for it.

It's training of processing speed. So, like, how rapidly your brain processes information, which tends to drop off some time around. 60 on average. If you look at like a big population of more than a million people, there was one study that looked at this. And there was a study going back to the 90s called the active study, which is still the biggest ever study of brain training in older adults. And one group in the active study, so there are three different training groups and a control group. And one group did processing speed training. And so what happens is information flashes up on a screen and you have to remember what you saw and where you saw it,

even if it only flashed up for like 200 milliseconds. And then if you're good at it, it will get harder. Like that time will get shorter and shorter. And it adapts to you to kind of push the edges of your current processing speed and make it a little better. And adults who did that training, it was 10 training sessions over six weeks and then boost the sessions at one year and three years.

They just published a 20-year follow-up. of the active study and that group had a significantly decreased risk of later dementia by like really challenging this processing speed aspect of the brain. Other forms of brain training don't have as good evidence as this specific type. It's been built into a platform called Brain HQ, which has been used in lots of studies now. So there is some evidence for brain training. But if you ever do, So the double decision in Brain HQ, which is the modern version of this task that did an active, it's actually very hard. And it requires, where you are really challenged to kind of process information rapidly.

So equally, I think you get the same thing by going and playing pickleball because it requires all those same kind of fundamental processing speed aspects. Plus you get physical activity and social connection and all this other kind of stuff. So you don't. Yeah, yeah. So I would advocate for doing it that way, but if you want to do some kind of formal brain training that does have some evidence for it, that would be the way to do it. So then it sounds like this particular type of thing. So we need focus and we need challenge. And there are lifestyle things that you're talking about here that can give us what we need. I mean, because I'm also thinking, what about learning a language? What about learning an art form or a craft that we're an absolute newbie at?

Like, we have no skill at. You know, do things like that make a meaningful difference? So I would argue, yes. There are a few different lines of evidence on the things that you've mentioned. So for language learning, some of the best evidence we have as it relates to later cognitive function and cognitive decline is actually people who grow up bilingual. If you grow up bilingual, you have a lower risk of later dementia. And I have some friends and colleagues who study this and it's thought to be because your brain is constantly juggling between two different

language systems, like suppressing one while using the other and switching back and forth, you get better at like processing complex decisions because your brain is sort of like used to having to do that. However, there are also studies in older adults where you have them join a language class or even use a duolingo app and you see some significant improvements in related cognitive functions, executive functions, so like being able to rapidly make decisions and maybe even some changes in the brain that kind of map onto that. There are also studies like for the other things that you mentioned. So you see something similar with music learning, even in older adults. And that works throughout the entire lifespan.

If you get kids and you teach them how to play musical instruments, their broader cognitive function improves as well. Then there was a very interesting study that came out recently called Creative Experiences and Brain Clocks. And what they did was they created like a brain age. So people might have heard of like a biological age. So like how old is your body relative to how old you are in years? And they did something similar for the brain by measuring electrical activity in the brain.

And when you measure electrical activity of the brain, you can measure which networks and areas of the brain are kind of talking to each other at different times. And one thing that we tend to see that happens as people lose cognitive function is that the fidelity of those networks gets a little fuzzier. They're not as efficient as they have been previously. So they basically created this brain age to say, how old does your brain look based on the fidelity of the function of these different networks in the brain, if that makes sense. And one of the most important networks for this metric was the fronto parietal network, which is just like the front of the brain to kind of like the middle backish of the brain. And that's really important for things like focus and attention. And the function of that network tends to decline with age. And what they found was that people who gained expertise in a creative art.

And so they had tango dancers, they had musicians, they had visual artists, they even had video gamers. And actually there's some very interesting evidence for complex sort of 3D immersive video games as being a potentially useful cognitive stimulus. As expertise was gained in these, well, as they call them creative arts or experiences, they saw significant improvements. in the structure of these networks and people's brains looked younger. Other studies have suggested, particularly in musicians, that amateur musicians have the youngest-looking brains because it's hard for them. They're engaging in it. So they actually get more of a benefit compared to an expert or a professional

where it's become, you know, it's no longer the same kind of challenge. So there are all these different pockets of evidence that suggest that engaging in something where you're a beginner that's challenging and then gaining expertise over time significantly improves both the structure and function of the brain. But I guess there's a warning in there also, right, which is, you know, let's say I start learning Spanish. You know, I'm 60. I start now.

And in five years, I'm pretty comfortable with it. And I can have an easy conversation with pretty much anywhere and where I go. Okay. So now my brain is able to focus and use the language. but the challenge part is not there anymore. So I've got to figure out, am I going to learn a new language? Am I going to do something else?

Does that track? So yes. And I think it is important to do it for long enough that you've actually gained some expertise, right? Because the alternative is the people like, well, I always want to be a beginner. So I'll do this for a month and this for a month and this for months. Right.

So you really want to engage in it and challenge it and challenge yourself and build expertise. Then there's two parts of this. one is do you want to maintain this skill? If you want to maintain the skill, you have to still engage in it. So there are studies that show that older pianists, right, even if they were experts or professionals, the thing that best determines how well they play is how much they practice. And that seems obvious. But you might think, well, if they're getting older, they'll just have fewer skills because they're getting older.

But no, actually, the skills relate to how much they practice. And so that's one thing that you have to do is think about how do I maintain the skills I want to keep by practicing them. And then the other part is, well, maybe I got so good at Spanish that, yeah, it's time to take up pickleball or jiu-jitsu or something else where you get a novel challenge where you can start to build skills again. Yeah. Is there a benefit in bringing on a new pursuit that is, not just a cognitive challenge, but also a physical challenge at the same time? I think so. And partly because we have some of the best evidence we have for exercise and cognitive function comes from coordinative exercise.

So if you compare two types of exercise, and there have been randomized control trials where, like, one group does cycling and the other group does badminton, or one group does circuit training and the other group does dance classes. and everybody benefits in terms of cognitive function because we know that exercise is so critical for cognitive function. But there are greater benefits in the group doing a more coordinated type exercise so a racket sport, a ball sport, a team sport,

dancing, martial arts, something like that. But then, so not only is that a great way to do your exercise because you get additional cognitive benefit, it. If that is then the way that you're doing complex skill learning, you're kind of like getting the most out of your, it's like the most efficient way to do it. So for people who are trying to think about, well, what should I pick to do, especially if they're pressed for time, I think learning a new, co-ordinative movement, sport, dancing, something like that, gives you your bang for your you also get more social connection often if you're joining a club or a class or something like that.

So like you tick so many boxes at the same time by doing those kinds of activities that not only do we have some like really nice evidence for it is also efficient. Yeah. So what I hear you saying is basically I have to start taking hip hop as soon as we're done talking. 100%. Yeah. I'm on it. You brought up a number of times now also the social aspect of it. Tell me more about about that. So we know from multiple kind of strands of evidence that social connection is just like a fundamental part of, you know, a fundamental requirement for human health. And we know, you know, similarly, if you're then socially isolated or you feel lonely or unsupported, that that has a number of negative consequences for our health. And there are some very interesting studies looking at individuals who've been social. isolated and looking at their brains. So like prisoners in solitary confinement or simulated Mars expeditions, which NASA has done a few times, you so like lock somebody on

their own for weeks at a time and see what happens to them. Or Arctic explorers who are on their own at the top of the world for months at a time. And you see changes in the brain that affect regions of the brain that we know are susceptible to the processes of aging and a really important. important for our like complex cognitive functions like the prefrontal cortex really important for decision making. They tend to sort of atrophy if we don't get this input from other people. And then there are studies that show that those who have fewer social contacts will become socially isolated over time, they have more accelerated declines in cognitive, in brain structure and function and cognition with that. So it seems to be like this fundamental requirement of humans that we

are connected to others, feel supported by others, and have this opportunity to look after others. A couple of interesting kind of caveats with that. One is that actually doesn't have to be humans. There are, there's some evidence that pets sort of provide a similar function in terms of maintaining cognitive health in older adults, particularly those who live alone. So as you're describing that, you know, what stands out to me also is that midlife and later life is often known as the time where social circles shrink. And that, if I'm hearing you correctly, that may not just be great just for our quality of life, but it also may not be great for our brain health.

So a critical part of this is what's sort of societally driven versus what's like driven by our own personalities. So often when you talk about social connection and social contact and social support. There's always people who are like, well, I'm an introvert and I don't like other people. So like, this sounds very stressful that you're saying that I need to go out and, you know, interact with all these people.

And so that's not what the research says or what I would say is that there's, it's all about quality rather than quantity. So if you don't feel lonely and you feel supported and like there's, you feel like there's somebody you can reach out to if you need them, then that's enough. So there's a colleague of mine, Ben Ryan, wrote a book called Why Brains Need Friends. And he kind of describes all humans as plants. So, and the amount of social contacts you need is the amount of water a plant might need. So

some are like tropical ferns and they need a ton of water constantly. But like some humans are succulents or cacti. And like the occasional rain once a month is plenty of right? So this can be very much tailored to the individual. But beyond that, we're thinking about how things change, you know, as we get older, our groups get smaller because we're busy, we're looking after the kids, right? We've got work. And so that's really where you kind of set the stage. Like we talked about midlife as this kind of setting the stage for what happens later. I think that's where our social contacts can really shrink. And that can set the the stage for issues later on because you don't speak to your old friends or acquaintances

for three decades. Then when you retire, they're not there for you to be, for you to be able to reconnect with. And so that's where, you know, as much as you can, staying connected to a group in some way, even if it's just like occasional touch points, it doesn't have to be you're spending a ton of time with them or traveling with them, right? It's just, it's just having these kind of touch points so that if, if and when you, need them, they're available to you. Equally, right, we've talked about learning new skills, classes, like, that is a great way for adults to make friends, is go and volunteer for something that you feel passionate

about, go join a new class where you're all beginners and you're all kind of in it together. I think that's a really nice way to do it, because otherwise telling, like, grown adults that the need to go and make some new friends. Like that, like, conceptually, that's really hard. Yeah,

exactly. Yeah. I love the invitation here to sort of say, okay, so we can bundle a lot of what you're saying into singular experiences in the form of classes or workshops or like go retreats, whatever it may be, where there's an activity where it's new to you,

you're not good at it, it makes you focus, it's really challenging for you. It integrates physical, movement sort of like and movement that also is not just repetitive but requires novelty and adaptation and then if we're doing it with other people at the same time it's like we're just checking all of these boxes in one experience and it's not just great for our mood and for our body and for our physiology it's also great for our brain health and for the longevity of maintaining

it absolutely yeah you you distill a lot of this into a fairly simple model the three s is walk me through this. It's a nice model to just kind of like hook into when you're trying to figure out what what can I be doing right now. Yeah, absolutely. So we've talked about a lot about a lot of stuff. And there are even more risk factors that maybe that we haven't touched upon yet. And when it comes to long term cognition and dementia risk. And it can very easily be overwhelming. I could give you a list of 20 things that are very evidence based. And. You know, anybody who's worked as a coach, I've worked as a coach in many different arenas. And one thing you will know as a coach is that if you give somebody 20 things to do, they will do zero things. And that is completely normal as an entirely, it's entirely normal. So as I sort of like spent time with the research and like doing the various strands of work that I do, I think most of the factors that build and support brain health coalesce into these three nodes of

of an interacting network that I call the 3S model. So the first S is stimulus. And we've talked about that a lot already, right? But we know that we need to challenge our brains if we want to build and maintain function. When you then challenge the brain or engage it in some complex task, the first thing it does is those areas of the brain being used, ask for a greater supply of the things it needs to do that job. So supply is the second S.

So you need. a healthy blood supply because that kind of responds to different areas of the brain as they're being activated. And so we know that heart health is really critical. And we kind of talked about this right at the beginning. So that's a critical component of supply is heart health. We also need a good supply of energy. So metabolic health, blood sugar regulation is really critical to. And we need a supply of nutrients that kind of build the structure, help make the neurotransmitters, that run these different processes in the brain. And there are some nutrients that we have very good evidence for

when it comes to long-term cognitive function. So omega-3 fatty acids, B-vitamins, iron, and vitamin D. Those are the ones we have the best evidence for. There are some others. But those are critical things we need to get from the diet. Then, right, you stimulated the brain, you brought in a supply of everything the brain needs to respond to the stimulus.

then we want to adapt to that stimulus, right? We think about memory, we think about consolidation. That's the same for skill building. That happens during sleep and periods of rest. So now we're in the third S, which is support. So a big part is sleep. Are we giving our brain a chance to rest and recover

from the stimulus that we've applied to it? Are we supporting those adaptations through other factors? So hormonal status is really important. it also we can produce factors that that help to support adaptation, trophic factors, a lot of those are produced during exercise. And then we want to avoid things that impair adaptation. And these tend to be things like smoking, excessive alcohol, air pollution, gum disease that causes a lot of sort of inflammation in the body and in the brain.

And something like chronic stress, which actually is almost like, if we can go back to the athlete analogy, it's almost like over-training for the brain. It just never lets it switch off and sort of really like rest and recover. And so all of those things are connected as well. And what that means is this isn't like some long laundry list of things you have to do perfectly. You can identify one factor. And as you start to make changes, like the whole network shifts in your favour. So sleep is a great example.

If you start to sleep a little more, say you know, you, you, you start to sleep a little more. say you sleep six hours a night and you're able to make a few changes so you can sleep for six and a half hours a night. Over time, we know things like your blood pressure will improve. Your blood sugar will improve. The next day, you're going to feel a bit more sociable because we don't feel very sociable when we're tired. You're also more likely to engage in cognitively challenging activities because we avoid those when we're tired. So all those areas I talked about starts to shift just because of one thing we changed. And exercise is the same.

You start to exercise more. That could be create a cognitive stimulus, could create a social stimulus, right? If it's pickleball, right? But you also sleep better, right? People who exercise more tend to sleep better. Or people who add a new cognitive activity tend to sleep better the next night. So all of this kind of interacts. And so you can identify one thing where you're like, oh, you know what?

I haven't been to my doctor and checked my blood pressure and my cholesterol. Right. those are a couple of things you can very quickly measure you can very quickly address if you need to then the whole sort of system starts to improve so that's how I think about it and that also helps us understand that even just one change in one area can actually create knock-on effects in multiple other areas as well okay so I'm going to ask you the obvious question here based on the fact that as you just shared a couple minutes before you've been a coaching role and you know that if you give people 20 things to do

They will do absolutely zero, and I'm raising my hand here because I've been the zero person many times, and I've probably been the person who's given 20 options and also seen everybody just like, you know, deer in headlights. So somebody's joining us. I'm like, okay, nodding along. Yeah, I get all these different things, and the whole bunch of things I could see. Is there sort of like a first domino that you think would be the most effective lever? for people to start with? So I think this changes a little bit by life stage.

And so say in kind of midlife, you know, still working, maybe 40s, 50s kind of time, there are two things that really stand out a lot to me. So one is that's the period of time when we start to see some changes in our physical health. just because we don't have the time to move, we don't think we have the time to eat, we're not sleeping properly, we're stressed. So it's a really good time to just like, you know, get a check up, check your blood pressure,

check your blood sugar, check your blood lipids, check your nutrient states if you can, you know, measure homocysteine for B vitamins, measure vitamin D, stuff like that. It's one trip to the doctor. And, you know, some of, you know, many of those things can be addressed with lifestyle. Some might need some medication.

But like, midlife is a really important time to sort of like get on top of that if you can, because that's when risk starts to kind of expand on that front. So one checkup to kind of take the status of your physical health and address anything that pops up is really important. Yeah. So it's like get your benchmarks. Get your benchmarks. Yeah. And then the other is that that group of individuals, they're probably like you and me, like probably the majority of the list.

they're probably getting lots of stimulus, right? They probably, you know, have high levels of education attainment. They have complex stimulating jobs. What they're probably not doing is thinking about the support bucket. Are they getting, like, are they getting sleep? Are they giving themselves breaks during the day? Are they structuring their workday? So they're not constantly task switching, multitasking,

just like this overwhelming feeling of stress that your brain never gets a break, right? So I think that get your benchmarks. see if you can start to build in some habits around, maybe improve sleep a little bit, maybe you just like give yourself some breaks during the day just to like let yourself take a breather, and it doesn't take much. Studies show that even just like five minutes outside,

a bit of breath work, something like that, is enough to sort of recharge you and you can go back into it. Then as you sort of like transition into that later period of life, maybe when we're nearing or thinking about retirement, this is the kind of stuff we were talking about earlier. That's the time to think about what classes can I join? Where can I volunteer?

What's going to be the next phase where I can engage, you know, stimulate my brain, engage with other people. That's going to be, you know, bring back some meaning, you know, learn new skills. That's where stimulus, I think, really comes to the fore. That makes a lot of sense to me. It feels like a good place for us to come full circle as well. So in this container of Good Life project, if I offer up the first, phrase to live a good life. What comes up? I think this process of being challenged and

building skills and then using those skills to kind of help others or help the world around you. Like I think this is something that is just so fundamental to the human experience. And that can look different for everybody. But there's something about, you know, developing expertise, being engaged and then using those in the world around you that I think is really important. And then, um, sort of as part of that, I think in reality, if your brain and body have done what you would like them to do when you would like them to be able to do it, that's, that's that, like, if, if, if, if you manage that in that, in, in, in, in, in that sort of like earlier context, I think that's a, that's a good life. It's often around, um, it's often around

other people. It's often around the skills that we build and the way that we engage. engage in the world. And then just being able to do, so being able to do the things we love for as long as possible. That's essentially it. And sort of all those little bits are baked into it. Thank you. So let's talk about some of the big takeaways here.

One thing I'm really sitting with is how much of what we call brain decline is really just a brain that stopped being asked to do anything hard. Tommy's 3S model, stimulus, supply, support is one I keep coming back to. and that distinction between encoding and retrieval change how I think about every, like, wait, what's that person's name moment that I have? I also loved his distinction between doing things that require focus and doing things that are actually challenging, that are hard, and the power of putting yourself in the role of a newbie, of not knowing how to do something, of being a beginner and struggling and fumbling,

so your brain can get the thing that it needs to really keep healthy. Bring it all together into one experience is fantastic too. So social interaction, physical movement, and brain challenge. All of these things are things I'll be thinking of as we move forward. And hey, before you leave next week, we're sitting now with Dr. Jessica Shepherd, along with a guest host, dear friend of mine, Karen Walron, to talk about why so much of what we've been told about menopause is either outdated or just flat out wrong. and what personalized care for this stage of life actually looks like.

Be sure to follow Good Life Project wherever you get your podcast so you don't miss that or any upcoming episode. And do me a favor. A quick seven second favor. Share this episode with just one person, especially anyone who you think has been kind of thinking about their brain health lately. Or leave us a review wherever you get your podcast. It really helps us get discovered and reach more people.

This episode of Good Life Project was produced by executive producers, Lindsay Fox, and me, Jonathan Fields. Editing help by Troy Young, Chris Carter, crafted our theme music. And of course, if you haven't already, please go ahead and follow us wherever you get your podcasts, so you'd never miss a conversation. Until next time, I'm Jonathan Fields. Signing off for Good Life Project.