How exercise slows down brain aging with Dr. Wendy Suzuki

We spend so much time focusing on how exercise changes our bodies — burning calories, building muscle, shedding fat.

What if the most important transformation is happening where you can’t see it? Hidden inside your skull, your brain is changing with every step, squat, and sprint.

In this episode, Wendy explains what happens inside your brain when you move, why it’s never too late to strengthen your mind, and the powerful ways exercise can slow brain aging.

You’ll also discover simple, science-backed habits — including her own brain-boosting routine — to help you stay mentally sharp for years to come.

Make smarter food choices. Become a member at zoe.com - 10% off with code PODCAST

Follow ZOE on Instagram.

Transcript

Jonathan Wolf: Wendy, thank you for joining me today. 

Dr. Wendy Suzuki: Thank you for having me. 

Jonathan Wolf: Oh, it's a great pleasure. I'm very excited about this topic. Now, we have a tradition here at ZOE, where we always start with a quick-fire round of questions from our listeners. Okay. It's designed to be really hard for professors, and that's because we have these very strict rules. You can say yes or no, or if you have to, you can give us a one-sentence answer, but it's a bit of a fail. Are you willing to give it a go? 

Dr. Wendy Suzuki: Absolutely. Hit me. 

Jonathan Wolf: All right. As we get older, Do our brains shrink? 

Dr. Wendy Suzuki: No.

Jonathan Wolf: Is it possible to grow my brain as an adult? 

Dr. Wendy Suzuki: Yes. 

Jonathan Wolf: Are there types of exercise that can make you smarter?

Dr. Wendy Suzuki: Yes. 

Jonathan Wolf: Is my risk of dementia fixed once I'm an adult? 

Dr. Wendy Suzuki: No. 

Jonathan Wolf: Can I reduce my risk of dementia just by walking more? 

Dr. Wendy Suzuki: Yes. 

Jonathan Wolf: I got one more, but you get a whole sentence for this one. What is the most surprising thing you've discovered about our brains? 

Dr. Wendy Suzuki: That moving your body is the most transformative thing that anybody can do for their brain health right in this moment. 

Jonathan Wolf: That's brilliant. I can see I teed up the questions and then you're like, this is easy, I'm a professor. Okay, well, you nailed it. 

So, Wendy, I'm really looking forward to this and that's because I know that a significant part of your career has been dedicated to studying how the brain forms and retains long-term memories.

I'm sure that everyone listening to this probably has a memory that holds special significance to them. I was thinking about that just this morning about what do I recall in particularly vivid detail. 

I suspect it's the answer that lots of people say, which is  the birth of my two children. I feel I can remember the sights and the emotions of that time really etched into my brain and I've already forgotten what I had for breakfast. 

How is it possible that these two memories of this thing that happened many years ago are created and somehow stored in my brain?

Dr. Wendy Suzuki: I love that you start with that particular example because I often use that example when I challenge people to think about that memory that they have that only lasted a moment, but they still have it after years and years. The moment that you hold your firstborn in your arms, yet so many of us can't remember what we had for breakfast this morning.

So, here's what makes memories stick, including that memory of your two children being born. Emotional resonance is so powerful in allowing things that happen in your life to stick in your memories. 

We remember the happiest and the saddest moments of our lives. And that is because right in front of our memory structure that is allowing you to remember that memory of the birth of your two children, is another almond-shaped structure called the amygdala.

The amygdala has so many close connections with the hippocampus, that structure critical for forming memories of events like the birth of children. But it's the amygdala that infuses that emotional resonance that when really, really amazing things and really, really sad things happen, it helps those memories stick.

But that's not the only thing that helps memory stick. Repetition. So you don't hold new children in your arms every single day, but that also helps things stick. That's a bread-and-butter kind of thing everybody remembers. 

Association. So we remember things better if they're associated with other things that are already in our long-term memory. And that just has to do with how the hippocampus, which is really an associative structure, it sticks things together in memories that happen at the same time. It is that thing that helps us remember the who, what, where, when, and how of a particular episode. And, that is how it kind of glues our perceptions together.

And novelty. Novel things are our first child. Never been through this before. That also helps things stick. 

So breakfast, by contrast, is not so emotionally resonant. You might have had the same thing or different things. It doesn't hit those marks. But the birth of your children, your first kiss, all these other things that we have such deep memories of, that hits all those marks of what makes memories stick.

Jonathan Wolf: So are there different types of memory or are they all the same and it's just that some of them fall away? 

Dr. Wendy Suzuki: Yes, there are many, many different kinds of memories and different brain structures that are responsible for different kinds of memories. 

So we've been talking about episodic memories, the memories of the facts and events in our lives. That's what most of us think about when we think about the memories of our lives that is dependent on the structure of the hippocampus. You have one on the right, one on the left. This is the brain structure that I've studied for the vast majority of my career.

But there are other memories, motor memories, the memory that you have for how to get your keys into your lock in that special way to get it open. It took a little while to get to learn how to do that same form of memory that you use to learn how to hit a forehand and a backhand in tennis, for example, very different brain structure. The striatum is involved in motor motor memories.

So lots of different forms, because we are remembering things in different ways in our lives. 

Jonathan Wolf: I'd love to start to talk about what happens to our memories as we get older. It's had quite a big impact on me throughout my life. My grandmother got Alzheimer's. It had a huge impact on my father who basically has sort of ever since then sort of lived his life feeling like that is the worst thing that might happen but also very worried that that might happen to him.

I think seeing someone go through this and sort of seeing these memories unravel is both awful, but also makes you realize how much it's the memories that sort of shape a person.

It feels like in general memories weaken. I feel that already my memory doesn't feel like it's quite as good as it was when I was 20. But I can see that obviously that can continue into old age. 

Why does that change as we age? 

Dr. Wendy Suzuki: Let me start with the good news. So often people I'm just going to say at our age, think, Oh, my memory is getting worse.

But actually part of what you're experiencing is more interference. You're probably doing more and juggling more and you know more people and you have more relationships to organize. 

Interference is very bad for your memory. When you're 12 years old, you don't have very many friends and you don't have that much to remember. And so it's easier to keep things, keep things in mind. 

So that hopefully will be helpful to help interpret part of what you and I, you know, think, Oh, I can't remember that. Well, we have a lot of, a lot more things. I certainly have a lot more things to juggle today than I did even 20 years ago. 

Jonathan Wolf: May I just say, I love that. I absolutely love the idea that my brain is still working. And actually, I'm just so busy. It's not that my brain is already falling apart. 

Dr. Wendy Suzuki: No, not at all. And I think everyone listening to this podcast can appreciate that even more. If you give yourself that moment of quiet meditation, self reflection to get rid of some of that interference of too many things going at the same time.

Do not read your phone while you're walking down the street eating a good or bad breakfast, that is adding to your interference. That is why a regular kind of mindfulness practice is helpful. It is clearing the garbage away so you can focus on those things that you do need to remember. 

In fact, I find that I'm better at remembering the things that are really important and kind of filtering out what is not good. But I do a regular daily meditative practice just for that purpose. 

Jonathan Wolf: Well, I'm going to come back to your actionable advice a bit later. But I find it incredibly positive that you're saying your brain is working better now than it was before. I think that's very exciting. 

Clearly, late in life, memory loss is clearly a real risk and I think a lot of people listening to this show, when they talk to us, particularly those who've become ZOE members, talk about what their health goals are. 

Interestingly, you know, brain health is often something they mention as much as physical health. It's a thing that they're worried about and they want to maintain.

So I’m 49, you know, what might happen as I get… Why is it that memories don't continue to work, you know, perfectly right up to death for everybody? 

Dr. Wendy Suzuki: Well, again, let me start with the good news. Sometimes they do and there's such a wide variety of aging, but when they don't, and you know, my father also passed away with Alzheimer's disease and I saw that happening. I recognized it very early on. 

He couldn't remember how to get back from the coffee shop that he went to every afternoon and that spatial memory is particularly dependent on the hippocampus. And when he came back complaining of that to my mother, I knew something was wrong with his hippocampus.

He was eventually diagnosed with Alzheimer's dementia, which meant that the cells in his hippocampus were starting to die. The plaques and tangles started in the hippocampus and then spread out into his cortex. 

So what's happening there? That is the cause of the most common form of dementia, Alzheimer's dementia. And that means that again, starting with the good news, long-term memories from your childhood, when you grew up, your high school years are often something that you remember so well. those are no longer stored in the hippocampus. So those memories, in as much as you've kind of maintained them over your long life, are still there.

But when you start to get damage to your hippocampus, you can no longer put new information into your long-term memory. So your breakfast, your lunch from yesterday, not going in there. So that starts to break down. 

I ask my students all the time. Would you be the same person if you didn't have your four years of high school experience and all of them say, no, I would absolutely not be the right person? So that damage to the hippocampus that starts to happen slowly in dementia in older age starts to wear away at your personal history and in your ability to do things and interact with the world. 

Jonathan Wolf: I’m looking for an analogy, so let me try this and tell me if I'm completely wrong. So I'm listening to this feeling it's a little bit, like when you take a photo on your phone, it's just on your phone, but then after a little while it backs it up into the cloud. And then even if you lose your phone, you know it's still there in the cloud and you can access it.

Is this a little bit of an analogy, you're saying you've got this hippocampus, which is a bit like my phone, it's dealing with this right now. But all going well, it's sort of pushing it into other parts of my brain whose name I've already forgotten, and sort of stores it. 

That's what normally happens, and you're saying that in this example with Alzheimer's, as we get old, that process of holding it in the first part just doesn't work. So I can't even make it through to this long term. 

Dr. Wendy Suzuki: Yeah. 

Jonathan Wolf: But you might still have the long term. Which is why I think one of the common things, you know, as a non-doctor, not a scientist, you know, you meet people who are having some of these memory problems, often they remember things a long time ago or general parts of their life, but somehow the last few years can just be almost… And they just sort of skip over it as if it hasn't happened. 

Dr. Wendy Suzuki: It's a strategy to kind of get through life. You use what comes up in your brain and because those new memories are not being laid down, you use what you have in there as habits and as reference.

I saw this in my father, there was a long time when I think he was having memory problems, but he covered very, very well because he knew the answer. He knew enough from the life that he was living about what to do when he needed to do it enough, but he was covering.

And one day he couldn't remember how to get back. It was just eight blocks away, this coffee shop.

Jonathan Wolf: We had very similar experiences with my grandmother. It’s interesting, I hadn't realized that the location thing was a particular thing.

But I remember actually being with my cousin, she was very little at the time and sort of got lost and it didn't make sense. She was an incredibly on-it woman. 

You're saying that this sort of loss of location-related things is a giveaway about this particular sort of damage. 

Can I ask Wendy, because we started talking about Alzheimer's in part because of my own family experience, but we think about forgetfulness and not being somehow quite as sharp as just a more common experience. 

I would say most people feel that it's an almost inevitable experience as you get older. Is losing your memory just the same as getting Alzheimer's? And does everyone end up getting Alzheimer's if they live long enough?

Dr. Wendy Suzuki: The longer you live, the higher probability you have of developing dementia and Alzheimer's disease. But there are lots of different reasons why memories might be harder to lay down.

One that is so relevant in this moment is stress and anxiety levels. Who does not have higher levels of stress and anxiety today than maybe 10 years ago before anybody had heard of COVID-19, for example?

Everybody has the example, you know, you're in a stressful situation and you're asked a simple question, and Oh, I can't, I can't remember. Does that mean you have dementia? No, it means that you are stressed. So that's one very common thing. 

I will say that stress and anxiety levels are a double-edged sword. I give the best podcasts that I ever give when I'm just a little bit nervous, I'm not sure exactly what's going to happen. I use that little bit of boost from stress and anxiety. And if I go too far over, then I can't remember all the stories that I want to tell you. And if I'm too relaxed, then I also don't like my performance.

We tend to catastrophize or clinicalize stress and anxiety. Oh, it's so terrible, I don't want any of it. No, every single one of us needs it in our lives. It is that motivational boost.

Before we went through COVID-19, perhaps we had a better appreciation of it. I'll also say that particularly for our younger generation, social media is leading to higher levels of stress and anxiety.

And that is not good if you're in a constant state of, Oh, I'm not good enough. I don't look this way, or I don't have this. That is not good.

But generally, a little bit of stress can help your performance be at its peak. 

Jonathan Wolf: And so is there a slow drip-by-drip sort of decline in my brain as I get older?

Because I think you're saying right now I'm fine, but before you get to something that you were calling sort of Alzheimer's, is there just a slow decline in my brain?

Which I think is what most people listening to this, that's sort of how they've been brought up in the same way that we're brought up that when you're old, you can't climb stairs and you're sort of, the same thing is that your brain just steadily gets worse, like your muscles reduce. Is that accurate? 

Dr. Wendy Suzuki: Again, I'm going to say that there is so much variability.

Yes, with aging, our muscle, our muscle fibers degrade and you're probably not going to be as strong as you are at 75 as you were at 25. But there are lots of things that one can do to strengthen that brain muscle that you have.

That is where all the science comes in, the science of sleep. You talk about so beautifully the science of nutrition, not only for your muscles and in your peripheral body but for your brain. The science of exercise, I know we're going to get to. 

The science of, of social connection. We are social animals and the longest-running study of happiness in the world. It was started at Harvard in the 1920s. And what brings a happy life since the 1920s, from the 1920s till today is the number of social connections that you have in the world.

So, all of these things contribute to this beautiful organ that we all have in our heads and how it works and how you're working it every single day.

Jonathan Wolf: I would love to transition now to the thing that you're really studying and interested in, which is how exercise impacts the brain. And my producer has told me that you have brought something that you want to use as a show and tell. Would now be a good time for that? 

Dr. Wendy Suzuki: Absolutely.

Jonathan Wolf: We don't normally get show and tell on a podcast. That's quite exciting. 

Dr. Wendy Suzuki: Okay, so I have a hat box here and I'm putting on some rubber gloves and in this hat box... 

Jonathan Wolf: Okay, it's definitely not a hat. 

Dr. Wendy Suzuki: Instead what I've brought for you today is a real preserved human brain. 

Jonathan Wolf: It's a real brain. Up until now, I thought it was just like a sort of clay model. Now I'm completely freaked. It is a real brain. 

Dr. Wendy Suzuki: This is a real preserved human brain. Her name is Betty. 

She is the most photographed preserved human brain on the East Coast of the United States because I bring her, well, I can't bring her out of state, but I bring her to all of my talks for thousands of students at NYU where I teach.

So here, let me give you a… for those of you watching it on video, a little tour. This is the front of the brain. This is the frontal lobe. If Betty was in my head, she would be sitting right here, transposed into my head.

This is right behind the forehead, right here, the frontal lobe, important for focus and attention, decision-making. 

Here, back here, here's the back of the brain, right back here. This is the part of the brain that we see with. So all of the nerves from your retina and your optic nerve go from the front of your brain all the way back and they connect to this primary visual cortex right here. 

Jonathan Wolf: So I'm actually seeing with the back of my head, even though I think I'm at the front of my head. Actually, it's all the back.  

Dr. Wendy Suzuki: You’re seeing with the back and that is why if you've ever kind of bonked the back of your head, you see stars, right? Because you've poked the visual cortex and so that evokes a perceptual sensation of visual stimulation because you poked the visual cortex. You don't get stars if you bonk the motor part of your brain, for example.

So between the frontal lobe and the occipital lobe, the back of the brain is the parietal lobe, important for processing relative spatial locations and decision-making. 

My favorite lobe is the temporal lobe here, right kind of below the temple. Why? Because that is where the hippocampus lives. 

Jonathan Wolf: And that's what you were saying that was where we store our memories as they're happening.

Dr. Wendy Suzuki: We are processing those memories. It is encoding those memories into long-term memory. And with repetition, those memories get stored out here in the outer covering of the cortex. But down here, right below this part of the temporal lobe, is where the hippocampus sits. 

And right here is called the cerebellum, or small brain. This is really important for fine motor movements, if you play an instrument, or anytime you walk down the street, it's actually a lot of coordination to walk without tripping and that is because we have a cerebellum that's helping us with that. 

But this is somebody's whole life, their personality. How they see, feel, think, smell, and laugh about the world is defined by the connections in, in this structure right here.

Jonathan Wolf: The first thing I'm struck by is how big it is. It's much bigger somehow than I really imagined it would be. I mean it's like a good size sort of melon size. It's a lot bigger than my heart I think would be, isn't it? 

Dr. Wendy Suzuki: Oh yeah a little bigger than your heart probably. 

Jonathan Wolf: And it's taken up most of what's inside my skull I guess looking at it. It's really big. It's not a very appealing color. It's a sort of brown. I at first thought it was clay when you took it out. It's like oh you've got a model because it looks sort of soft and a bit squishy. 

Dr. Wendy Suzuki: So it's brown, it's this brown because it's been sitting in formaldehyde for many, many years. It's much lighter in our actual heads.

But you're right that it's large. It is dense. I mean, this, it's not just a fluffy structure. And if I'm pulling the two hemispheres from the right and left open, if you can see how deep it goes in. This is folded cortical mass and the amount of folds basically correlates to our brain power as humans.

This would be much larger if I unfolded the cortical surface out on this table. It would drape over the edge of the table that you are sitting at right now. So for example, a rat brain is much smaller. It's just an inch and it is smooth, no folds. 

Sorry rats. I mean, you navigate the subways in New York beautifully, but you don't have the computational power that humans have, as we're seeing right here.

Jonathan Wolf: I mean, I just said it's large, but actually it's pretty small, right? You're factually able to hold it in your palms quite comfortably. It weighs, how much? 

Dr. Wendy Suzuki: About three pounds. 

Jonathan Wolf: About three pounds. It's just over a kilogram. And I compare that with the enormous number of servers that are having to be done for things like ChatGPT, that people listen to this. It's definitely not as clever as a human being yet.

And you just see just how extraordinarily efficient that is as a thinking machine. And that it has personality and a sense of self, self-awareness, and consciousness. All this is rather, it's amazing. 

Dr. Wendy Suzuki: I'm thinking of a different answer to the question you asked at the top of the show. Which is, do you realize that there are only two kinds of cells that make up the entire human brain?

Jonathan Wolf: No, I had no idea. 

Dr. Wendy Suzuki: Neurons, which are the workhorse cells, and glia, which have been described as support cells, but we now know they're doing much more in terms of computation, even some cognitive functions. But only two basic types.

The connections between those two simple types of brain cells are what defines us as people and allow us to think, fall in love, and remember the birth of our Children and all the other things that the brain does.

Jonathan Wolf: And it's sort of soft, right? There's nothing rigid holding this together. 

Dr. Wendy Suzuki: It's like firm tofu, I would say, in the head. 

Jonathan Wolf: Firm tofu is quite soft. That is remarkable. 

Dr. Wendy Suzuki: I mean, that is why helmets are so important. 

Jonathan Wolf: So it's going exactly the same way. When you look at that, it makes you think how unprotected it is if you fall off your bicycle or somebody tackles you in a sporting game or something like that, it's really remarkable.   

Dr. Wendy Suzuki: It is, but I will say, this is another thing that people don't realize. So surrounding this, of course, is our skull, which is hard. 

I don't want my precious brain banging up onto the skull. And it doesn't because between the skull and the brain is basically kind of a, think of it as a fabric sack that covers the entire brain. Between the sack and the brain is a water, it's cerebral spinal fluid, so it's like a little water bed for your brain.

But that is the protection between your precious neurons and glia in your brain and the hard skull or the football player or soccer player coming at you to tackle you.

So I'm a big proponent of non-trauma, no trauma for your brain. 

Jonathan Wolf: Amazing. 

Dr. Wendy Suzuki: Would you like to hold Betty? 

Jonathan Wolf: So I'm a little intimidated, but I also feel one's supposed to face up to one's fear, so yes, I think I would. 

And I'm guessing I need a pair of gloves. 

Dr. Wendy Suzuki: Yes, you should put gloves on. 

Jonathan Wolf: So how old is Betty?

Dr. Wendy Suzuki: So, Betty has been in the Center for Neuroscience, my department at NYU, since I got there 26 years ago. 

Jonathan Wolf: Wow. I am as intimidated as I am when a friend passes over their three-day-old baby and the one thing you mustn't do is drop the baby. Just don't drop Betty. 

Dr. Wendy Suzuki: But there you go. Impressions?

Jonathan Wolf: Well, the first thing I’d say is Betty is heavy because on the outside, it looks sort of a little squishy. So you think it's going to be like a sponge, but Betty is heavy.  

.Dr. Wendy Suzuki: Betty is dense.

Jonathan Wolf: A couple of pounds, a kilogram, something like that. It's very weird to imagine that you're holding the brain of a real human being and that all the emotions, fears, and loves were happening in here.

I think the other thing that I'm struck by, completely differently from that, is we do a lot of AI at ZOE. There's lots of data scientists and computer scientists and you know, everybody listening will be familiar with things like ChatGPT recently, that are remarkably human-like in some ways. They use huge numbers of computers taking up vast amounts of power and huge amounts of space. But they're not as smart as Betty would have been. Or able to do many things or be self-aware.

Yet Betty's in fact really small, you know, squishy and it's remarkable, right, the capacity within our brains when you look at it like that. It seems crazy to think that you can think and feel with this. It's amazing. 

Dr. Wendy Suzuki: Yes, small and squishy, yet the most complex structure known to humankind you are holding in your hands right now, Jonathan.

And that's what I think about every time I pull Betty out of this hatbox. This was somebody's whole life. I mean, I've spent my whole career trying to understand how that works. 

We know an enormous amount about neuroscience, but we don't know what happens in the brain when we fall in love exactly. What are those synapses that go off? 

Jonathan Wolf: There is no love cortex in here?

Dr. Wendy Suzuki: There's not a love cortex. We know that our fear areas of the brain don't work as well, so we tend to become more fearless when we are in the throes of deep romantic love. 

Jonathan Wolf: I love that. It is extraordinary. And I know that, you know, everybody working on AI actually is basically wanting to learn more from the brain because it is so much more complicated, we understand so little. 

It's amazing. Thank you very much.  I'm going to pass her back. I'm going to feel immediately massively more relaxed at the point I passed her back and haven't dropped her. 

Thank you very, very much for bringing her in. I think it is really an amazing way for all of this to go from being very abstract because it's in the brain and it's hidden, to sort of seeing it for real and this thought that there are things that I could do to actually make it work better for longer. It's amazing. 

Dr. Wendy Suzuki: I'm gonna put Betty down now so we can continue our conversation. 

Jonathan Wolf: Well, that's quite intense but really remarkable. I have never seen someone's brain outside of their skull before, and I'm okay with keeping it that way. 

I think seeing it in real life does make you even more see that this is this real organ, it's not just this abstract personality, which is, I think, how I tend to think about it. And you were talking earlier about, you know, how as we get older, basically this organ can get less efficient.

Do any parts of it shrink or is it just that it stops working as well? 

Dr. Wendy Suzuki: So lots of different things happen. There are loss of synaptic connections. Synapses are the connections between individual brain cells. And it's not so much… people think, Oh, there's widespread cell death. Cells aren't dying in normal aging. It's usually the synapses that leave and that are damaged and that's the most common thing that's happening with aging. 

Jonathan Wolf: So basically the connections between the different cells in my brain, there were lots of them and there's less, and losing those somehow reduces how well it works and processes every part.

Dr. Wendy Suzuki: But actually going back to something that we talked about before in terms of stress, not all of us have the level of stress that comes with PTSD, but we also know that PTSD, long-term stress in situations of war, does lead to an overall shrinkage of the brain, particularly in the temporal lobe.

That is because we know that high levels of cortisol can first start to damage those synapses, the connections, but then high levels of constant cortisol will start to damage your brain cells.

That's not the most common thing that happens with aging, but that is something that we know is leading to the shrinkage that people are scared that's happened to your brain. It does happen. It's not the most common thing happening with the vast majority of the population. 

Jonathan Wolf: So most people are not going to see this, but if you're under very intense stress and you talked about combat or something, literally the brain itself, parts of the brain will get smaller.

Dr. Wendy Suzuki: Yes. 

Jonathan Wolf: So, is it possible to do anything to prevent the loss of these, you know, connections between these cells, prevent this damage to your brain as you get older? 

Dr. Wendy Suzuki: Yeah. So, this is kind of the topic that I've studied for the vast majority of my career, which is the area of brain plasticity. How things in the environment, things that you do, how you live your life, how it affects literally the anatomy, physiology, and function of your brain.

There are two flavors of brain plasticity; positive brain plasticity, where the experiences that you give yourself can increase size, increase function, and negative brain plasticity, which we just talked about. PTSD, long-term stress, can take those connections away, can make sizes smaller in particular brain areas.

Jonathan Wolf: And are there real scientific studies that have demonstrated this? 

Dr. Wendy Suzuki: Absolutely. For all the musicians out there it's clearly shown that long-term practice at the level of a professional musician will increase the size of your motor cortex specific for if you're a violinist, it's the left hand that gets so much work.

If you're a pianist, it's both hands that will change the size and representation of those motor areas that you are working. 

Jonathan Wolf: So my mother made me practice an instrument every morning,  from when I was four, and I kept doing this until I was growing up. And then I dropped it quite fast after I left home. I'm sorry, Mom. 

Have I got any long-term benefit from that, or is the fact that I've dropped it now mean that I lost out on any of the plus? 

Dr. Wendy Suzuki: You probably have a little bit of it left. You could probably relearn pieces faster than somebody that never practiced for those years. But no, it doesn't last for a lifetime.

You can't kind of take one summer and say, okay, here's the exercise I'm going to do for the rest of my life. And it's going to last. It really does have to be a regular habit that you form. 

Jonathan Wolf: I had a terrible feeling you were going to say, it's a bit like exercise and good food, right? I can't just eat really well last decade and then just have ice cream and burgers. 

Dr. Wendy Suzuki: Sadly, no. 

Jonathan Wolf: So other than playing music really well every day for the rest of my life, is there anything else that can help to improve this brain health? 

Dr. Wendy Suzuki: Absolutely. So many different things. I'm going to start with my favorite, which is moving your body.

Physical activity is so powerful. As I said, my most amazing thing is that moving your body is the most transformative thing that you can do for your brain. And I think people realize that moving your body is great for your heart and cardiovascular and your muscles, but they don't realize that, in this sense, your brain kind of acts like kind of a muscle.

And what is happening is different from when you're using weights or running for your muscles. What happens is every single time you move your body, there is a rush of neurochemicals that gets released in your brain, and those neurochemicals are the secret for why exercise is so transformative. 

Let's go for the immediate benefits that happen with this rush of neurochemicals. You get dopamine, serotonin, noradrenaline, and endorphins released with exercise. I'm not talking about marathon running, I'm talking about a power walk, a 10-minute walk that you can take at lunch. Walk up and down the stairs during your day. That can lead to this rush of neurochemicals that I like to call a bubble bath of neurochemicals that happens every time you move your body and that's going to lead to an immediate mood boost. 

Now, is that going to change your mood for the rest of your life? No, the duration of that mood boost is going to depend on how long, and how hard you worked out. And there's a bell-shaped curve there, but that's not all you get. 

Moving your body also improves the function of your prefrontal cortex, the one right behind your forehead, really critical for your ability to shift and focus attention.

You and I as a podcaster and a teacher, need our prefrontal cortex to remember questions that were asked and the questions we want to bring up, and that single bout of exercise can help with the functioning of that prefrontal cortex. 

The third thing you get is reaction time. So your ability to respond to a question is faster after a single workout than if you didn't work out at all. And this is all having to do with that bubble bath that you're giving your brain. 

The most transformative thing happens when you don't just do a one-off exercise. I was just going to try it once, Okay. I did it. I got the bubble bath, you know, give me all the benefits. You get a short-term benefit with a single exercise bout. 

Let's say you include more exercise in your life, which I call long-term exercise. And you do that on a regular basis. That means your brain is getting more of a bubble bath. And here I'm going to add one other element to that bubble bath. Okay. that gets released every time, which is a growth factor called BDNF or brain-derived neurotrophic factor. This goes to my favorite structure in the brain, the hippocampus, and it actually helps the hippocampus grow brand-new brain cells.

So I like to say regular exercise is going to make your hippocampus big and fat and fluffy. And that is what you want. You want the biggest, fattest, fluffiest hippocampus that you can have. It's also actually changing the size of the prefrontal cortex. Not because of new cells, but because of new synapses.

So that is the transformation. 

Jonathan Wolf: That all sounds pretty amazing. And if I just caught that bit at the end, what you're saying is that although you said at the beginning that maybe our brain overall doesn't grow, you're saying that this particular part, which is your favorite part of the brain, I never had a favorite part of the brain before, but I like that you have a favorite part of the brain, actually grows as you are doing this exercise on a regular basis.

Dr. Wendy Suzuki: Yes. It does. And also, even if you don't do any exercise, every one of us has a little bit of, it's called neurogenesis, the birth of brand new brain cells in our hippocampus. But with exercise, I like to think of the image of a watering can of growth factor that goes up and down the hippocampus every time I'm working out.

This is my nerdy motivation to work out in the morning is I want that watering can of growth factor going into my hippocampus and growing as many brand new brain cells. Because those brain cells mean my memory is going to be better. And my hippocampus is going to be bigger and fatter and fluffier.

I have Alzheimer's in my DNA. My father passed away with Alzheimer's and I am not curing Alzheimer's with my exercise and the increase in BDNF in my hippocampus. 

But I'm making the hippocampus as big and fluffy as it can be so that it's going to take longer for that disease to start to affect my memory than if I didn't work out and my hippocampus was skinny and small and unfluffy.

I don't know what the opposite of fluffy is, but that is the goal and that is the power of what exercise is doing for every single one of us. 

Jonathan Wolf: And Wendy, I just want to be really clear about this, if you are doing this exercise regularly, it actually does reduce your risk of getting dementia as a result?

Dr. Wendy Suzuki: There are many correlational studies showing that the more you work out, either in mid-age or in older age, the lower the probability you have of developing dementia. 

But overall, you know, as we get older and older and older, you're still overall increasing your probability of getting that dementia. But it makes sense with the anatomy and what we know about the positive brain plasticity, that physical activity gives to your brain, that staving off of the onset of dementia with regular exercise makes perfect sense with the neuroscience that we know. 

Jonathan Wolf: That's amazing. And when you say brain plasticity, that's the same thing about it being flexible and able to make these connections.  

Dr. Wendy Suzuki: Yes, well brain plasticity refers to the change in anatomy, physiology, and/or function. It's a broad term. So what I'm telling you about with exercise is a literal change in anatomy.

I should point out that not all brain areas in the adult human brain can grow new brain cells. In fact, only two can. One is the olfactory bulb that isn't affected by exercise but is affected by lots of different smells. So you'd expect a sommelier or a chef to have a big, fat, fluffy olfactory bulb. 

Jonathan Wolf: I've never heard of that before. 

Dr. Wendy Suzuki: And the second brain area that all of us have the potential to grow new brain cells is the hippocampus. And the best way to do that is to move your body more. 

Jonathan Wolf: Is there a point at which it's too late for exercise to help with your brain health? You know, if I'm listening to this and I'm 80, is it like there's nothing more to be done? Or does this affect relevant for anybody? 

Dr. Wendy Suzuki: It is never too late to start to move your body and there are studies showing that even people in the early stages of dementia with mild cognitive impairment improved their dementia score with regular physical activity appropriate for that age group. They're not running marathons. They are walking supervised either on a track or on a treadmill. 

But that absolutely shows that. In fact the other amazing finding is that they have shown that people even in their 90s are growing new hippocampal brain cells.

So even that ability to grow new hippocampal cells is there in your nineties., That doesn't prove that with exercise you can grow more, but you are still getting new cells. There's the signature of those brand-new cells, even in a 90-year-old. 

Jonathan Wolf: That's amazing. And I love the idea that it's never too late to do something, which I always find incredibly empowering.

I think one of the things that I most love about all the different conversations that we've had on the podcast over the last couple of years is I was sort of brought up with this idea that your genes are your destiny and there's basically nothing you can do, you're just fixed on this path. 

What I love listening to you is you're saying, even in your 90s there are things that you could do that can really affect your outcome. And it doesn't guarantee anything, but the point is you're not just stuck on the path. And I always find that, at least for me, it feels incredibly empowering. There's something that I can do. 

Before we move to really actionable advice about what, you know, practically what we might do, I just wanted to pick up on one other thing.

You talked about the amazing short-term impact of doing this exercise with these bubble baths of happy chemicals whose names I've already forgotten. 

Is there any long-term impact on psychology, how you feel and your regular cognition, not anymore talking about how I might be protected when I'm much, much older. But if I'm doing this regularly, is this going to have an effect on me after a week or a month or a few months?

Dr. Wendy Suzuki: Yes. Yes, absolutely. So let me tell you the two most common findings in the whole wide literature on the effects of exercise on the brain. 

Number one is long-term exercise changes your baseline mood state. You have higher levels of good emotions and lower levels of more difficult emotions, you know, stress, and anxiety absolutely goes down. That is very, very common in the literature. 

The second, kind of equally common finding with exercise is that you get better, you improve your ability to shift and focus your attention. Predominantly dependent on the prefrontal cortex. 

I can't emphasize how important that is in our world when our attention is being torn from your phone to your laptop to the people in front of you to the bike that's about to run you over on the street.

So many things that we have to pay attention to and that improvement of prefrontal function is, you asked me, that's why I hesitated, you asked me, can exercise make you smarter? Improved attention is the actual finding that I point to. 

Am I smarter with a better prefrontal function? That's why I hesitated. And my answer was, yes, I feel better, I'm able to perform better with a highly functioning prefrontal cortex. 

There are also studies showing that hippocampal function changes, but it seems like you need longer exercise regimens to really see the benefits of that.

There was one really great study where six months of increased exercise, you can see the graph line going up, and it was only after a year that everybody started to merge on this. 

So, this is not an immediate, you know, I'm gonna get a big, fat, fluffy hippocampus in the next two days. No, it takes a little time. This is cell growth, and it makes sense, but there's also great evidence, particularly in animal studies, showing how powerful exercise is to grow your hippocampus.

It reminds me of all the amazing data from the blue zone areas. These are not people that go on a fad diet or a fad exercise regimen. These are people that live in the mountains all their lives. They walk up and down and up and down the mountain and they eat very little red meat and they, they eat a lot of pickles or, you know, all these things that are great for your gut microbiome. Not for a fad their whole life. 

And what happens? They live to over 100 with good cognition, not degrading. And that's it. How can you make not a fad diet, but how can you make this part of your everyday living?

Jonathan Wolf: I love that. And we actually did a podcast with Dan around blue zones. So if anyone listening to this is interested, they can, if they search for blue zones, they will find it. 

So somebody is listening, they're completely sold on exercise. What can they do? And do they have to become a marathon runner?

Dr. Wendy Suzuki: So first you don't have to become a marathon runner. Walking/power walking works just fine for mood. That immediate mood benefit that we talked about after a single workout, just walking for 10 minutes, getting outside, walking for 10 minutes. 

I think so many of your listeners will have experienced that already, but the key to getting those long-term changes, especially the big fat fluffy hippocampus and prefrontal cortex is doing anything with your body that increases your heart rate. That's called aerobic activity. 

Let me emphasize again, that power walking will get your heart rate up. And I like to say that, even if you haven't started, it's not part of your regimen, it actually is faster to get your heart rate up when you're just starting out, than if you have a regular exercise regimen, it's like, Oh, I have to get into there for at least 30 minutes before my heart rate gets up.

So all the beginners have a little advantage there, but every moment that you get that heart rate up for whatever you do, including fun things like dancing, gardening, and walking around a museum, there are so many creative ways that you can do this. That is what's going to give you that big, fat, fluffy hippocampus, prefrontal cortex, and beautiful brain.

Jonathan Wolf: And is it more important therefore to be doing faster steps than to be doing more steps as I listened to that? 

Dr. Wendy Suzuki: That's a great question. I would say that those that are doing lots of steps, maybe at a lower aerobic activity can put on their to-do list, add more fast steps to that. And those that are doing small numbers of steps maybe have higher aerobic activity.

I like to say every step counts, every step counts. People come up to me all the time [and say] all I do is walk. I'm like, that is great. Celebrate that. People don't realize that walking to the store, walking from your car to the store, and walking around a shopping mall, all of that counts too.

So just try and get more. And I think the secret is not just more, make it fun, because if it's not fun and enjoyable, you're not going to do it. 

Jonathan Wolf: That's fascinating. What sort of exercise target should someone be thinking about? And I'm sure you're saying it's different based upon their starting point, but how often a week,  how much time do people need to devote?

Join the community

Be the first to know about ZOE’s breakthrough research, content from the world’s leading scientists, and more.

Because I think sometimes you listen to things on the internet, it's, well, if you're not doing three hours of crazy exercise, none of this matters. Is that the reality for your brain? 

Dr. Wendy Suzuki: No, it's not. And I can be very specific because one of my goals over the last 10 years has been to try and head towards a prescription of exercise. People want to know exactly how much. 

So I'm going to start with a study we did in people who were not exercising so much, less than 20 minutes a week for the last three months, 20 minutes of exercise per week. 

And what we showed is in those people, that three times a week, aerobic exercise, 45 minutes each, there's the specificity, got them baseline mood changes, improved prefrontal function, and improved hippocampal function. Three months of that. 

Jonathan Wolf: And so again, how much was the exercise they were having to do? 

Dr. Wendy Suzuki: Three times. Actually, what they ended up doing was between two and three times a week, I think it was 2.6 times a week on average. This group did 45 minutes each of a, it happened to be a spin class. So it was, we chose a class where clearly the goal was an aerobic activity.

So that got these brain plasticity changes. That was, we were thrilled with that. 

Jonathan Wolf: That's amazing.

Dr. Wendy Suzuki: Then I have one more piece of data to give you, which is what about mid-fit people, people that are exercising. Maybe two on average, two times a week, but a good, spin class or run or something like that. What about them? 

Well, we did a study in that population and we said, okay, exercise as much as you want for the next three months. We're going to give you free workouts again at a spin studio. And we had people that went seven days a week for a 45-minute class and those that stayed at two times a week.

What we found is every rotation of the wheel helped. The more you worked out at this mid-fit level, the more benefit you got in all of these things in mood, in focus. And in memory,

I like to say every step, every drop of sweat counts. Whether you're just starting out, you're in the middle, and Olympic athletes, I would love to do a study on you because I know what the outcome is and I would love to show that.

But most of us are not Olympic athletes, which is why I started with the lower-fit people and the people exercising twice a week.

Jonathan Wolf: That's amazing. I know you've said that there's a way to eat your way to a sharper mind. Could you tell us more? 

Dr. Wendy Suzuki: Yeah, so the amazing data on nutrition and the brain focuses mostly on the Mediterranean diet and or the mind diet that focuses on decreasing inflammation, which we know is very bad for the progression of dementia and Alzheimer's disease.

So Alzheimer's is the most common form of dementia. I didn't mean to refer to those two things as separate. They are one and the same. 

Also, it comes up back in the blue zones. A lot of these blue zone areas follow that general pattern of less red meat, more colorful, lots of fruits and fresh vegetables.

Not exactly vegetarianism, but lots of fruits and vegetables. And so, those are the things that have been associated with the longest longevity and the strongest kind of cognitive function over aging. 

So I mean, personally, that is what I try and follow. 

Jonathan Wolf: We're very interested in the Mediterranean diet and food more generally. And then we're really interested in this question about personalization on top. 

One of the things that our research and other research has shown is that the way that people respond to the Mediterranean diet varies from person to person. So it's not all exactly the same. And our hypothesis has been that partly that's because of the different gut microbiomes that people have.

So over the last year or so, we made a big breakthrough where we identified 50 gut bacteria, which is called sort of good gut bacteria, 50 bacteria that are called bad gut bacteria, that are linked to positive health markers and negative health markers. 

When you become a ZOE member, you get this personalized nutrition program that tells people how can you add in particular foods. It's actually targeting, getting more of these good bacteria. 

We found with this randomized control trial that we published in Nature Medicine a few months ago, that after about sort of four to five months of following this personalized nutrition program, the vast majority of these ZOE members actually had a better gut microbiome.

Wendy, are you surprised by that or does it sort of fit in with I guess what you've seen in this thinking about the way in which the the diet is linking to your health and your brain  

Dr. Wendy Suzuki: It doesn't shock me and I should say that I have not touched the nutritional aspect. I did not control nutrition in these studies and I think that that's why the studies that you and your colleagues are doing are so important.

Yes, I think that's such an exciting area of research the link between the gut and the brain, which is a new and emerging and really, really exciting research area.

And just like so much in our health, it's never going to be one size fits all. And it's easier to speak to the generality and that's where the general Mediterranean diet is great. But it's so powerful to know that there is not just the idea of personalization, but there are kind of actionable items that you can add to that.

So it doesn't surprise me. As you know, it's hard to control what people eat. It's hard enough to control how they move their body to take on both at the same time.  I need 10 times the number of team members as I think you can appreciate. 

Jonathan Wolf: So I can totally appreciate it. And I think this is an area that we're increasingly interested in. 

I think that it's interesting that you mentioned sort of inflammation has been an important part of what you think is going on in the brain because that seems to be what a lot of the scientists who've been coming on this podcast are talking about. 

This role between food and the microbiome, means that a simple picture that I understand is that most people walking around in the Western world now are just living with a lot more inflammation than we did in the past.

And it's interesting that you're talking about this affecting the brain and they're often talking about it affecting other parts of our health. 

Dr. Wendy Suzuki: Yes. Yeah. There's more and more research on how. bad inflammation is for the brain. And that's one of the things that exercise can help with. That's why we need all of us working.

We all can't be, you know, the experts in all of these different things, but they all work together in this amazing kind of physiology that we have. 

Jonathan Wolf: Can I finish with one final question? So I think a lot of listeners here are going to be going away feeling very motivated, but also I think often there's a big gap from motivation to doing something.

How could someone who's listening and saying, I want to develop my own brain health routine? How can they do that and not sort of just feel stuck? What would be the key components you would be suggesting to somebody that they could go and keep going? 

Dr. Wendy Suzuki: Yeah. So this is what I suggest to my students. And it is the idea of a personal experiment, a personal exercise experiment. 

The idea is to choose a doable increase in physical activity that you can fit into your very busy schedule on a regular basis. And note what that does to these things we've been talking about. 

To your mood is probably the easiest to modify. In fact, you are the best arbiter of what your mood is. There's not a good external measurement of your mood, but also focus and energy levels are also great to use. 

And so the idea is, kind of monitor how you're feeling on a regular week, change this for a week, once a day, make it doable, make it something that can fit into your schedule and note that, and everybody can get more sensitive to how exercise is affecting you. 

I mean, I'm sure this may be part of what you challenge your ZOE members to do. What does a sugar-filled diet make you feel? I know that it makes me feel awful. But in fact, by contrast, a fruit-filled, summer diet, Mediterranean, pretending I'm in Italy makes me feel wonderful.

So same thing with exercise. And that is so powerful because you can start to use that personal sensitivity to create your own workout and to add in you don't want to add too much either because too much is going to make your muscles hurt and make you too tired. You can't live in your day. 

What is the perfect amount of movement that makes your brain work better? It makes you feel better. 

Jonathan Wolf: I'm Wendy. You are basically one of the world's experts on exercise and the brain, maybe the world's expert on this. You're also obviously very busy. 

Dr. Wendy Suzuki: Oh, yeah. 

Jonathan Wolf: So I think everyone's going to want to know what's your personal exercise routine. 

Dr. Wendy Suzuki: Yes. So my personal exercise routine kind of developed during the pandemic. I used to be a regular gym goer and I couldn't go to the gym during the pandemic. So I started doing online workouts. And I love the convenience of being able to do that. 

So even today, I do a 30-minute cardio strength kind of workout and when I need a rest and a stretch, I'll add a yoga, a 30-minute yoga for me. 

30 minutes was perfect because it fits into my schedule. I could push hard and I'm not so sore the next day, even if I try and really push really hard and I feel the difference during my day when I do that. 

I did it this morning and I could tell that I did it. Of course, if I have a 4 am flight, I don't do it. But building that muscle of consistency and finding that duration that is right for you at your age and your fitness level. It was key for me, but that's what I do in my life. 

Jonathan Wolf: So 30 minutes a day, do you have a lot of equipment that you need at home in order to do what you're doing? 

Dr. Wendy Suzuki: I do. I have a yoga mat and I have a set of weights. Every time I use the weights,  I want two more, maybe a five and an eight, but I just use what I have and it's great. 

I know what pushes me, which is really higher cardio with weights is a great way to get your heart rate up. And I love kickboxing. I also know what I love. I love doing kickboxing workouts, which is really, really fun. And then I always say yes to an invitation to a class with other people, not in my living room.

So that's how I do it. 

Jonathan Wolf: Amazing. So that sounds, apart from the kickboxing sounding a bit intimidating, but until you said that, that all sounds quite accessible. You're saying a yoga mat, a couple of weights, and  an online class that you can just dial into can achieve all these amazing benefits you're describing.

Dr. Wendy Suzuki: Absolutely. And, you know, this was after I needed to go with other people with a really motivating instructor that had really great music. And I did that for many years, but I built my regular exercise muscle there. So that's why I can do it. 

Maybe you need to go with a friend. Maybe you need to recruit a friend because a friend and being there in a class where everybody can watch you was very motivating for me earlier in my exercise journey.

Jonathan Wolf: I think that's fascinating. I mean, my own personal experience is what I really need is a trainer, which is a bit like having a class and a friend because it's the commitment. Because basically if I don't have that, I'll skip it and I'll do some more work. 

But if I have somebody who's waiting for me, Yeah, absolutely turn up because it would be rude not to and that is an enormous part of the thing that makes me do the exercise. Because the truth is I've done it for quite a long time now since I've started to realize it's really important for my health.

But I've never quite hit the point where I really feel good about it in advance. I'm always reluctant before I start and then afterwards I feel really good. So I need that sort of reason to be pulled. 

Wendy, I thought that was brilliant. I would like to try and do a quick summary if that's all right. You just let me know if I get anything wrong and correct it. 

So then we started by saying that the longer we live, the higher the risks we have of dementia or some other sort of issue with our brain. But the good news is there are things that you can do about it. And we mainly talked about exercise and you gave this brilliant vision that just moving my body in a power walk creates this, I think you said bubble bath of neurochemicals.

And they have an immediate impact. So actually I can remember things better. I can have a better reaction time. I can feel better just almost immediately after that because of all these chemicals. And if I do that regularly, I start to get all of these other benefits. 

And you said, actually, in that case, I can grow new brain cells in part of my brain. That was the hippocampus. Is that right? You pointed out on the brain, but I can't remember where it is. Gets bigger, fatter, and fluffier. And these are all good things. 

Even if you're listening in your 90s, you could be doing something and you could actually be improving it. So it's amazing. It's not just something that you have to do when you're 20s. And the more that you work out, the lower the probability that you will develop dementia. 

But it's not just about avoiding Alzheimer's and things like that. Actually, long-term exercise has lots of other benefits. You said it can improve your mood in the long term, really reduce anxiety and stress, and make you feel happier. And that, therefore, it's just all-around great for you. 

And then we got on to say, what could you actually do? And I think the thing there again was it's amazingly accessible. What you said was that even if you are just walking for 10 minutes, you can have an immediate impact on your mood. 

That the key thing I think you said is you need to raise your heart rate. So aerobic meaning raising your heart rate, you said. So actually just power walking can do that. Dancing or gardening. 

And actually, if you aren't doing a lot of this, I love this, you're actually an advantage. If you're like Peter Atiyah, you've got to work for three hours before you get any benefit. But if you're a normal person I can raise my heart rate really fast because I'm not that fit, so you can get a benefit really fast. 

And you said the science says that even two to three times a week of 45-minute exercise had a real impact on the brain,. But wherever you are, if you lift your exercise, it gets better.  And that will improve your mood, your focus, your memory.

And you talked about your own experience where, you know, you're doing this every day because you're clearly maximizing your brain health given what you described about your own personal experience. And even then, 30 minutes a day, you do from home, and you believe you're really making a difference to your brain.

It's amazing. Thank you for sharing all of that. 

Dr. Wendy Suzuki: Thank you for having me.