Recap: How exercise slows brain ageing | Dr Wendy Suzuki

Summary

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ZOE Science & Nutrition Recap: How Exercise Slows Brain Ageing

Guest: Dr. Wendy Suzuki (Neuroscientist)
Host: Jonathan Wolf (ZOE)
Release Date: February 17, 2026

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Episode Overview

This episode focuses on how physical activity benefits the brain, especially as we age. Dr. Wendy Suzuki, a leading neuroscientist, discusses the science behind brain plasticity, how exercise acts as a potent brain-boosting tool, and distills actionable advice for maintaining brain health well into later life.

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Key Discussion Points & Insights

1. The Ageing Brain: What Really Happens?

• Brain Shrinkage vs. Synaptic Loss
  • With age, the brain doesn’t typically lose lots of cells (neurons) but instead loses the connections (synapses) between them.
  • Quote [00:50, Dr. Suzuki]: “There are loss of synaptic connections... It’s the synapses that leave and that are damaged. And that's the most common thing that's happening with aging.”

2. Brain Plasticity: Positive & Negative

• The brain remains changeable (plastic) throughout life.
• Positive brain plasticity: Activities and experiences can physically change the brain for the better (e.g., increasing size, function).
• Negative brain plasticity: Harmful experiences or chronic stress can damage the brain and shrink areas (like PTSD).
• Example [02:22]: Musicians who practice intensely develop larger areas of their motor cortex specific to the muscles they use.

3. Are Early-Life Skills Permanent?

• Skills like musical ability, learned intensively early in life, bestow some residual benefit but are not permanent if one stops.
• Regular practice is essential for lasting effects.
• Quote [03:14, Dr. Suzuki]: “No, it doesn’t last for a lifetime… It really does have to be a regular habit that you form.”

4. Movement: The Most Powerful Brain Support

• Exercise as Brain Maintenance
  • Physical activity is the most transformative action for your brain.
  • Unlike muscles, with exercise, the brain is bathed in a “bubble bath” of neurochemicals with every movement—even a brisk walk counts.
• Immediate effects of exercise:
  • Mood boost
  • Improved focus (prefrontal cortex function)
  • Faster reaction times
• Quote [04:17, Dr. Suzuki]: “Moving your body is the most transformative thing that you can do for your brain. Every time you move your body, there's a rush of neurochemicals that gets released in your brain. And those neurochemicals is the secret for why exercise is so transformative.”

5. The Science of “Bubble Bath” Neurochemicals

• Key chemicals released include dopamine, serotonin, noradrenaline, and endorphins.
• Even short bouts (a 10-minute walk, walking stairs) can bring benefits.
• The benefits scale with frequency and duration.
• Memorable Analogy [06:19, Dr. Suzuki]: “You get a short term benefit with a single exercise bout... but the most transformative thing happens when you don’t just do a one off. Regular exercise is going to make your hippocampus big and fat and fluffy—and that’s what you want!”

6. Neurogenesis: Growing New Brain Cells

• The hippocampus, vital for memory, actually grows with exercise due to the action of “brain-derived neurotrophic factor” (BDNF).
• Even minimal exercise leads to some new brain cell growth, but more regular activity maximizes this benefit.
• Quote [07:37, Dr. Suzuki]: “With exercise, I like to think of a watering can of growth factor that goes up and down the hippocampus every time I'm working out.”

7. What Kind of Exercise? How Much?

• You don’t have to run marathons!
  • “Power walking works just fine for mood.” [08:24, Dr. Suzuki]
• Any activity raising the heart rate (aerobic) provides significant benefit: walking, dancing, gardening, or even briskly strolling through a museum.
• Exercise has both immediate and long-term cognitive effects.
• Tip [09:51]: “Every step counts... the secret is not just more—make it fun! Because if it's not enjoyable, you're not gonna do it.”

8. How Much is Enough? (Specifics from Research)

• Dr. Suzuki’s research: Even in people starting from almost no exercise (less than 20min/week), simply doing aerobic exercise three times a week (45 minutes each, e.g., a spin class) for three months led to:
  • Improved mood
  • Better prefrontal cortex function
  • Enhanced memory
• For more active people, increasing frequency brought additional gains; every session mattered.
• Quote [11:49, Dr. Suzuki]: “They ended up doing... 2.6 times a week on average. This group did 45 minutes each... and got these brain plasticity changes.”

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Notable Quotes & Memorable Moments

• On regularity vs. one-off efforts:
  • Dr. Suzuki [03:14]: “It really does have to be a regular habit that you form.”
• Motivation to move:
  • Dr. Suzuki [07:37]: “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.”
• On making movement enjoyable:
  • Dr. Suzuki [10:10]: “Make it fun. Because if it's not fun and enjoyable, you're not gonna do it.”
• All movement counts:
  • Dr. Suzuki [09:51]: “Every step counts, every step counts.”

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Key Timestamps

• 00:50: How ageing impacts brain synapses, not cell count
• 02:19: Scientific evidence for brain plasticity; musicians’ brains
• 03:14: Skill retention needs regular upkeep
• 04:17: Neurochemicals and immediate exercise benefits
• 07:37: “Watering can” of growth factor and neurogenesis motivation
• 08:24: Any aerobic movement suffices; power walking for mood
• 09:51: All steps count; importance of enjoyment
• 11:06: How much exercise? Dr. Suzuki’s prescriptions from research
• 11:49: Study results: tangible cognitive gains from ~3x/week, 45min sessions

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Actionable Takeaways

• Do any movement that raises your heart rate; it needn’t be intense or prolonged.
• Make movement enjoyable and habitual—consistency trumps perfection.
• It’s never too late or too little to start reaping cognitive benefits—every step, every drop of sweat counts.

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This episode distills neuroscience into everyday wisdom: move regularly, make it fun, and your brain will thank you at every stage of life.

Transcript

[A]

Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today we're asking how can we boost our brain? Our brain is a living morphine organ that is constantly responding to the stimuli we feed it. So the big question is, what sort of stimuli will keep our brain strong and healthy? Is it brain puzzles, supplements? Neuroscientist Dr. Wendy Suzuki believes the most powerful way to support your brain is by simply moving your body. And she's joining me today to explain why. 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?

[B]

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.

[A]

So basically, the connections between the different cells in my brain, there were lots of them and there's less and less. Losing those somehow reduces how well it works and processes every part. So is it possible to do anything to prevent the loss of these connections between these cells, prevent this damage to your brain as you get older?

[B]

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. And there's 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.

[A]

And are there real scientific studies that have demonstrated this?

[B]

Absolutely. For all the musicians out there, it's clearly shown that long term practice at a level of a professional musician will increase the size of your motor cortex, specific for that. 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.

[A]

So my mother made me practice an instrument every morning, like from when I was like 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 mum. Have I got any long term benefit from that or is the fact that I've dropped it now means that I like lost out on any of the.

[B]

Plus you probably have a little, little bit of it left. You could probably relearn pieces faster than somebody that never practiced for those years.

[A]

But.

[B]

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 gonna do for the rest of my life and it's gonna last. It really does have to be a regular habit that you form.

[A]

I had a terrible feeling you were gonna say it's a bit like exercise and good food. Right. I can't just eat really well last decade and then like now just have ice cream and burgers.

[B]

Sadly, sadly, no.

[A]

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?

[B]

Absolutely. So many different things. I'm gonna start with my favorite, which is moving your body. Physical activity is so powerful. As I said, my most amazing thing is 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 like, it acts kind of like 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 is 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, endorphins released with exercise. And 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 gonna lead to an immediate mood boost. Now is that gonna change your mood for the rest of your life? No. The duration of that mood boost is going to depend on how long, 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 as a teacher, need our prefrontal cortex to remember questions that were asked and the questions we wanna bring up critical. And that single bout of exercise can help with the functioning of that prefrontal cortex. And 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. But the most transformative thing happens when you don't just do a one off of exercise. I'm just gonna 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 gonna add one other element to that bubble bath 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. And so that is the transformation.

[A]

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.

[B]

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 a watering can of growth factor going into my hippocampus and growing as many brand new brain cells cause those brain cells means my memory is going to be better and my hippocampus is going to be bigger and fatter and fluffier.

[A]

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

[B]

Yeah, yeah. So first you don't have to become a marathon runner. Walking, slash 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 for 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, 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, but every moment that you get that heart rate up for whatever you do, including fun things like dancing, gardening, walking around a museum, there's 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.

[A]

And is it more important therefore to be doing faster steps than to be doing more steps?

[B]

As I listen to that, 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 into that, and those that are doing small numbers of steps that maybe have higher aerobic activity. I like to say every step counts, every step counts. So don't People come up to me all the time. I go, 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 to get, 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 gonna do it.

[A]

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 like, how often a week, like how much time do people need to devote? Cause I think sometimes you listen to things on the Internet. It's like, well, if you're not doing three hours of crazy exercise, none of this matters. Is that the reality for your brain?

[B]

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 and of exercise. Like, people wanna know exactly how much. So I'm gonna start with a study we did in people that 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.

[A]

And say again, how much was the exercise they were having to do?

[B]

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 we chose a class where clearly the goal was aerobic activity. So that got these brain plasticity changes. That was. We were thrilled with that. And then I have one more piece of data to give you, which is what about mid fit people that are exercising maybe two on average, two times a week. But a good, you know, 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 gonna 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 to three times. Yeah, 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, you know, 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.

[A]

As you can imagine hosting this podcast, running Zoe, juggling family life, it all keeps me pretty busy. So I try as best I can to stay energized and show up well in all those parts of my life by fueling my body with the right food, by exercising, and by adding a scoop of daily 30 to my meals every day. If you haven't heard of Daily 30 yet, it's the gut supplement designed by our gut health scientists here at Zoe. It's made of over 30 high quality hand picked plants including seaweed, fungi and different types of fiber. Better yet, it contains ingredients that support gut health, digestion and energy, which is ideal for packed calendars and busy lives. Simply add one scoop a day to any meal for an extra boost of fibre and plant diversity. And because it tastes delicious on just about anything and adds a satisfying crunch, it quite quickly slots into your life, becoming a daily healthy habit you you'll always have time for. By the way, whenever we talk about Daily 30 as a good source of fiber, we're required to say that it contains 4 grams of total fat per serving. Obviously that's all amazing healthy fats from plants, so order yours [e-mail] daily30. Thanks for listening and see you next time.