BITESIZE | The Most Powerful Daily Habit for Better Brain Health | Louisa Nicola #585

9 Oct 2025 · 24 min · 12 chapters

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In short

This Bite Size clip argues that exercise is the most powerful daily habit for brain health, improving “gray matter,” neural networks, mood, and longevity while reducing dementia risk.

Guest

Louisa Nicola, a neurophysiologist and brain health researcher who cites research (about 1,500–2,000 references) linking aerobic and resistance training to brain changes.

Key claims

aerobic exercise increases BDNF (brain-derived neurotrophic factor), which crosses the blood-brain barrier and supports hippocampus growth (a key Alzheimer’s-affected region). Exercise also boosts mood-related neurochemicals and is “not part of natural aging.”

Notable examples

zone 2 training at ~65% max heart rate (conversational pace) for at least 3 hours/week; walking up hills for ~20 minutes weekly; “gamified” interval walking up to a house/door count. She also recommends strength training 2 days/week (compound moves like squats/bench presses; or wall sits/calisthenics for beginners).

Written by AI. May contain mistakes. Listen to the episode to check what was said.

Chapters

Tap a time to open that second in VO

The Power of Exercise for Brain Health

0:09 to 1:20

Discover how exercise enhances brain health and functionality.

“So, why might you consider bringing AG1 into your life?”

The Power of Exercise for Brain Health

1:30 to 2:43

Discover how exercise enhances brain health and functionality.

“If they have more gray matter, what is that?”

Understanding BDNF and its Benefits

2:43 to 4:19

Learn about BDNF and its role in brain health and memory.

“And aerobic exercise, which isn't actually that difficult, is going to help you do that.”

The Importance of Movement at Any Age

4:19 to 6:13

Why starting to move, even at a small level, can change your health.

“I think I read some research a few years from Art Kramer.”

Exercise as Medicine

6:13 to 8:00

Explore the concept of exercise as a vital health intervention.

“no matter how old you are, that's absolutely going to make a difference in the future.”

Recommended Guidelines for Physical Activity

8:00 to 10:46

Understand the recommended levels of exercise for optimal health.

“I wish everybody would exercise for their brain health and for health outcomes and longevity rather than aesthetics.”

Training Zones and Their Impact

10:46 to 13:18

Learn about different training zones and their effects on health.

“And it's around 80 % people who are not meeting the physical activity guidelines.”

The Impact of Exercise on Cancer Cells

14:03 to 16:16

Learn how exercise can help combat cancer by increasing natural killer cells.

“And the way that it does that is there's three ways.”

Adapting Exercise for Different Age Groups

16:17 to 18:40

Understand how to tailor exercise intensity for various fitness levels.

“I think walking up hills is one of the very best forms of movement.”

The Importance of Movement as You Age

18:41 to 20:21

Discover why staying active is essential for brain and heart health as you grow older.

“I think my last paper, there's about 1 ,500 to 2 ,000 references.”
Show all 12 chapters

Strength Training's Role in Longevity

20:22 to 22:10

Explore how strength training contributes to muscle mass and overall health.

“Am I fortunate to have some autonomy in my life to do this?”

Accessible Ways to Start Exercising

22:11 to 24:06

Learn easy methods to begin strength training, even for beginners.

“I think Gabrielle Lime was on that as well.”
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Transcript

Automatic transcript. May contain errors.

0:00Today's Bite Size episode is sponsored by AG1, a daily health drink that has been in my own life for over seven years. So, why might you consider bringing AG1 into your life? Well, there are many reasons, such as enhanced gut health and support for your immune system. But one of the main reasons, I would say, is to help you with your energy levels. Now AG1 contains a blend of different nutrients including B vitamins, vitamin C and magnesium which can help reduce tiredness and fatigue and give you a boost in energy. And unlike caffeine, these nutrients actually work with your body's natural energy systems and don't have a negative impact on your sleep.

0:47Right now, during the month of May, AG1 is offering my listeners a brilliant deal. Your first month's subscription will be only£59, saving you£20 off the regular price. On top of that, you'll get a free welcome kit, a shaker bottle, a scoop, five travel packs and a bottle of vitamin D3 and K2 drops. You can see all details at drinkag1.com forward slash live more. Welcome to Feel Better Live More Bite Size, your weekly dose of positivity and optimism to get you ready for the weekend. Today's clip is from episode 522 of the podcast with neurophysiologist and brain health researcher Louisa Nicola.

1:39Louisa believes that exercise is one of the most powerful tools we have to protect and enhance our brain health And in this clip she shares simple practical strategies that we can all adopt whatever our age or fitness level

1:59You mentioned that aerobic exercise can increase the grey matter of the brain Yes That sounds really great I'm sure to many people in terms of what that actually means for them. If they have more gray matter, what is that? Is that the way they process information, the way they think? Absolutely everything. Your brain is responsible for everything that you do. It is responsible for who you are, how you see, how you interpret information, how you sleep, how you eat, even down to the spouse that you choose. If you have a better functioning brain, more gray matter, more functional neural networks, You will perform better, think faster and live longer.

2:42It'll make you a better human. And aerobic exercise, which isn't actually that difficult, is going to help you do that. Absolutely. And what are the mechanisms there? You mentioned BDNF. BDNF is one, yeah. Through exercise, through a specific pathway, it's the myokine pathway. When we are engaging in aerobic activity, we get this expression, this release of a growth factor. It's called BDNF. Okay, so what is BDNF? And is it aerobic exercise that specifically increases it? Or do other forms of exercise like resistance training and high intensity training also do it? Yeah. So BDNF stands for brain derived neurotrophic factor.

3:25It is a growth factor for the brain, meaning that when it is expressed and you have to be, let's just say we're at that zone two, right, where running, it gets expressed into the bloodstream. So it's a little hormone, if you will. And when it does, it goes through the bloodstream up into the brain. It does cross the blood brain barrier. But this is a really great thing. It gets in there and it goes into the hippocampus. The hippocampus is this seahorse shaped structure deep in the temporal lobes. And when it goes in there, it basically helps you grow new brain cells in that area. Now here's the here's the phenomenal thing.

4:02That is the first structure of the brain to go during Alzheimer's disease. That is the part that holds your memories, short-term memories. That's where memory formation occurs. And we've seen now through human studies that the hippocampal sub-regions, the areas around the brain can also change in structure, but the volume of the hippocampus grows. It increases, becomes more dense. I think I read some research a few years from Art Kramer. And from recollection, it was people in their 60s, maybe in their 70s. Yes. And just from walking, not that much every week. You may know the study to hand, I think a year later, the hippocampus looked bigger.

4:49Yes. And that's because the starting point, they were very inactive. Okay. Yes. So that's really interesting. So if you're really inactive, anything you do is going to make a difference that's the great point that's really empowering for people because you don't want you know when we start talking about zone twos and zone fives and high intensity and vo2 maxes and i want to talk about all those things i think some people who don't move that much are like yeah i mean that all sounds great but i don't know where to start like i don't really move much at the moment so i think we want to leave that message at least that, hey, it doesn't matter where you are, just start moving a bit more.

5:28Even if that involves you walking for 10 minutes a day, you know what's really great? If you live around hills, just walk for 10 minutes a day, maybe get on one hill, just get out and just do it easy. Because when you do, you will feel the benefits. By the way, BDNF, when it is expressed, it doesn't just help with hippocampal volume. We get other things as well. It helps with the expression of different neurochemicals that are involved in mood. We know that there is a direct correlation between depression and exercise. Why is that? Maybe it's because you're changing the structure of your brain through physical activity.

6:06And this is one of the things I love the most about your message. It's very empowering. The message you're putting out there to the world is very much about saying to people, look, there is so much that you can be doing right now, no matter how old you are, that's absolutely going to make a difference in the future. 100%. We think about Alzheimer's disease as this one point in our life, in our 70s that we're diagnosed with. When you actually are diagnosed in your 70s or in your 80s, that disease has been accumulating since your 20s, your 30s and your 40s. Right now, Alzheimer's disease, 55 million people worldwide have this disease.

6:45That number is going to triple by the year 2050. In the UK, Alzheimer's disease is the second leading cause of death and the first leading cause of death among women. Now, two out of three Alzheimer's disease cases globally are female. So that's something to consider. I think there's a common belief in society that our brains are going to decline as we get older. I think many people believe that Alzheimer's is an inevitable consequence of the aging brain, but it's simply not the case, is it? Absolutely not. And I always tell people that dementia is not part of the natural brain aging process. The lifestyle factors we've sort of touched on, exercise, sleep, stress, and food, they're all important.

7:35yeah but if you had to pick one for people to focus on is there one that comes to the surface for you i don't think any other intervention can compare to exercise i believe that exercise is the panacea for health exercise is medicine and our muscles are like pharmacies so your recommendation for aerobic exercise is what like for optimum brain health at minimum three hours per week of 65 of your maximum heart rate that zone two zone okay so conversational pace a little bit out of breath yeah but not too out of breath three hours yeah okay fine so that's minimum minimum so at least half an hour a day yeah which i think is pretty reasonable and i do you want to make things accessible to people at the same time you want to be honest with them and sort of go listen you have to move your body and for the people who are like but i don't have enough energy this actually helps you create more energy when you're training in this zone you're trading the mitochondria which is the the powerhouse of our soul where we produce our energy to work better to function better to create more of itself yeah so you can have more energy what do you wish everyone knew about exercise in the brain?

8:57I wish everybody would exercise for their brain health and for health outcomes and longevity rather than aesthetics. In my world, people are, but that's a mere probably 10 % of the population. The physical activity guidelines globally state that we should be exercising around 150 minutes to 300 minutes per week. And that's moderate to vigorous physical activity. Which means what? Exercising at around 65 % to 75 % of our maximum heart rate. Are you able to give some examples of activities that might fall into that category? Yeah. So imagine you are running up a flight of stairs and you are going full force.

9:40And the last step is when your heart rate, you feel like it's going to come out of your chest. you've reached most likely your maximum heart rate. Let's just say that's 200. Okay. Okay. You want to be working. I mean, that would be very high. That's a young person. Let's just say 100 then just for argument's sake. That means that we want you working out at 65 % of that 100 beat. That is your maximum heart rate. So we want you to be working out for 150 minutes at 65 % of your 100. So 65 beats per minute. Okay. So that's going to depend on who we are and what our maximum heart rate is. But essentially, we're talking about things like a pretty fast walk.

10:29Fast walk. Yeah. Fast paced walk, a jog, an easy jog where you can hold a conversation, but you feel like you're working out at the same time. Do you agree with those physical activity guidelines, first of all, or do you think they are conservative? They're conservative. And it's around 80 % people who are not meeting the physical activity guidelines. In what countries like America and the UK? Yes, correct. Yeah. Okay. And we know that physical inactivity is one of the leading causes of premature death globally, right? So that's pretty well established. So I know, because I've spoken to people in public health over the years, that sometimes public health guidance is given, not necessarily because it's optimum, but because it's like, well, if we push it much beyond this, no one's going to do it.

11:19Yes. Right? And so what is enough in your view based upon the research that you've seen? Yeah. That also, people don't know how many times am I meant to be doing weight training? How many times am I meant to be doing aerobic training? So they're just compiling it all together. So let's break it apart. Your aerobic training should be made up of at minimum three hours a week. So aerobic training are things like your long distance running, cycling, anything where you're able to move at around that 65 % of maximum heart rate. So you don't feel as though you're crushing it or you're pushing hard. It's quite, you know.

12:00Aerobic. It's easy. It's your long, slow distance running, I call it. So what about someone who doesn't run? Your brain doesn't know the difference between you running, cycling or swimming. It just knows heart rate. So get on a bike an elliptical trainer at the gym anything that is that cut it's in the cardio zone of the gym Anything that's just going to get you into that steady state Of 65 to 75 percent and you don't have to push yourself hard here. I think that's important, right? So you should be able to have a conversation whilst doing this. Yes, and at the end of every sentence you should be like You know, you have to take a breath Okay, so you're lightly exerting yourself, but your heart rate is certainly elevated compared to when you're just sitting down.

12:42Yes, right. When we talk about zones, we talk training zones. Zone one, we are sedentary. That zone two is that next level up, 65 % of maximum heart rate. Everyone needs to understand it's very individualized. Your zone two is different from my zone two. If I am not very metabolically fit, my zone two might be fast-paced walking. We've got zone three. And then when you're in that zone four, I call that the death zone. That's when you are working so hard running up those stairs to your maximum. The death zone. Yes, the death zone. When we are training in that zone four or zone five. So this is more intense.

13:23This is intense, yeah. High intensity. High intensity, right? So that's the sprints. That's when you're running up those stairs where you're really struggling to get air. Many things are happening in this zone. You're doing a lot for cancer outcomes and for brain health outcomes. So remember, when you're training at that zone, you're getting a massive shunt of blood to your brain and to the rest of your body. During that process, during the sheer force and the shunting of the blood, you are able to have an effect on 13 types of cancer. You are able to inhibit 13 types of cancer through this type of training.

14:05Wow. Yeah. And the way that it does that is there's three ways. The first one is when you exercise in this zone, you are increasing your production of natural killer cells. And these natural killer cells, they're a lymphocyte, but without getting too much into it. These natural killer cells are able to locate a circulating tumor, circulating tumor cells and kill them. These circulating tumor cells are abundant through our body if we have a tumor. Let's just say you are diagnosed with stage one cancer, which is the best type to get diagnosed with. There is a tumor that has formed somewhere in your body.

14:44What happens is that tumor, some of the cells tend to break off and we call these circulating tumor cells and they roam around through the body looking for a different site to lodge and create another tumor that we then move into metastases. During that process, these circulating tumor cells through the body can actually be ameliorated through the sheer force of this blood flow via that maximal aerobic exercise. Wow. Yeah. So it's helpful for your brain function as you age, but it's also helpful for reducing your risk of getting cancer. Absolutely. Okay, there's going to be some people listening who go, well, I'm no longer physically capable enough to run up a flight of stairs.

15:31You are at your age and your fitness level. I am. But some older listeners may go, well, hold on a minute, I can't do that or I feel that would injure me. Yes. These heart rates and these zones are all relative to your own baseline, right? Right. So what someone in their 30s might do might be different from someone who's 70. Yes. And so what I do with my parents is I get them to walk up a hill. We've got this steep hill back at my home that I grew up in. And once a week, they have to walk up and down that for 20 minutes. And let me tell you, they are getting to their maximum. I even get to my maximum if I'm jogging up.

16:12It is really steep. They have to take some breaks as they're going up. They're not running. They are just walking up a hill. I think walking up hills is one of the very best forms of movement. It really is. And look, it only needs to be done 20 minutes a week. So this kind of training, in terms of your brain prescription, you're saying three hours aerobic, 20 minutes of this form of exercise. Okay. I mean, one of my favorite recommendations to patients over the years regarding intensity depending on their age would be okay where you live okay walk around the block as a warm-up and then if you're back at your house see in one minute walk as fast as you can and see what number door you get to okay when you get there walk back yeah relaxed and you come back hopefully by the time you're back to your house you're feeling really relaxed and you've recovered and then go again as fast as you can and see what number house you can get to and maybe do that four or five times and then what I really liked about it was a very simple and accessible way for people to start playing around with intensity and using their inner competitiveness to go oh you know I got up to number 24 yesterday after two weeks of doing it I could get to number 28.

17:44So you're gamifying it. Exactly and I found for people who maybe get put up by going to the gym or maybe hill walking seems like something that they can't do I found that quite useful. So you're saying that exercise is probably the number one thing that people can do and focus on to protect their brains long term. Yes. one of the mechanisms by which exercise does all this magic in our bodies and frankly our brains is through bdnf brain derived neurotrophic factor and you're saying that we need to do a minimum really of three hours aerobic exercise a week okay and where have these numbers come from this three hours of aerobic, the 20 minutes of intense training.

18:36Like this is all coming from the research that you've studied, right? Absolutely. Everything I'm talking about, I've researched thoroughly. I think my last paper, there's about 1 ,500 to 2 ,000 references. And that's what I do daily. So they're very gold standard when we come to academic research. Yeah. One of the biggest things I've changed in my life over the past two years is my levels of physical activity. You have to love it. Yeah. You've got to find something that you love and something that's going to allow you to do this regularly without it being a real pain. And everyone's got something they can do if you find it.

19:17I guess for me, I've realized that when you really dive into the research on exercise and longevity and brain health and cancer and all these things, it's very hard not to come away with a conclusion that despite the common narrative that society today often puts out, which is, you know, take it easy as you get older. I kind of feel that's problematic. I feel the older you get, the more you have to be thinking about moving your body and not allowing yourself to get sedentary. So what does that mean for me? I now, I would say 95 % of the time I'm walking for at least an hour a day. Like it's just something I've decided.

19:59I made a decision in my brain, a conscious decision a couple of years ago. So no, Rangan, listen, if you want good brain health, good heart health, if you want to be functioning as well as you can, as you get older, if you want to be the best dad, the best husband, the best son, you have to move your body. You cannot let other things get in the way of that. Am I fortunate to have some autonomy in my life to do this? Yes, I am. But nonetheless, with the autonomy, I've made that choice. And that's kind of like a minimum. I do other things as well. But one hour's walk is kind of a minimum for me.

20:36Yeah. So how important is strength training? Oh my gosh, strength training, I believe, is probably fundamentally the most important part of exercise. Really? Many reasons. One, you're increasing your muscle mass. We know that at the age of 40, we get a decline exponentially in strength and mass. Think about muscle as your reserves. Muscle is an endocrine organ. It stores a lot of our mitochondria where we produce all of our energy. It helps us and stabilizes us as we get older. But it's the journey of building the muscle that is the most important. Because when we are strength training, we are releasing and expressing a whole host of myokines.

21:24Now, we mentioned BDNF, that's a myokine. But oh my gosh, strength training releases another 100 of them. Myokines are muscle-based proteins that when they go into different organs in the body, the brain, the liver, the pancreas, they have positive effects. So for the brain, they help preserve the synapses. They help the other neurons survive. They help with the growth and proliferation of other neurons in the hippocampus. So they're doing the same thing as BDNF, but they're doing even more than that. BDNF just goes into the brain, but these myokines can actually go elsewhere. Do you have a specific recommendation for resistance training?

22:09So in the paper that I authored alongside our friend, Dr. Tommy Wood. I think Gabrielle Lime was on that as well. Gab was on it too. Yeah. So this was at minimum two days a week. And this is compound movements. What does that mean for people who've never heard that term? So that's just squats. Instead of doing the designer aesthetics, okay, you want to be doing things that move as many muscle groups as possible per exercise. So not the bicep curl while looking in the mirror. Not the bicep curl, no, no. So you want to be doing squats, bench press, walking lunges are great. Anytime you can really work the lower part of your body as well, just due to vector size of your quads, for example, you're just increasing your gray metal.

22:53Now, let's talk about somebody who doesn't even, and they've never been into a gym before. you can still get the same benefits. We have a close family friend and she's kind of like a grandmother to me. She's 98 years old. Cognitively, she is firing. She's unbelievable. She's maintained exercise and dancing her entire life and social interactions, right? If I was to tell her to increase her muscle mass, we just have to get her to wall sit. She can increase her muscle size in her legs and get massive gains if she was just to wall sit. For me, that wouldn't work because I have stronger legs and I'm much younger than her.

23:37What I mean by that is if you are completely sedentary and you want to start lifting weights, you don't have to go into the gym and pound these weights. As I'm saying, you can start with calisthenics, which is just body weight movements. Start with doing some pushups. You can go onto YouTube and just type in beginner workouts for 50 year old females. I set them up for my mom all the time when she tells me she doesn't know what to do. And that's how you can start. Yeah. So don't allow where you currently are to put you off getting started, basically. If you take nothing else from this, just this idea that you can do something at home that literally is changing the structure and function of your brain.

24:23Yes. That's pretty empowering. That is the most beautiful thing about exercise. Hope you enjoyed that bite-sized clip. Hope you have a wonderful weekend. And I'll be back next week with my long-form conversational Wednesday and the latest episode of Bite Science next Friday.

From the publisher

Do you think that it’s inevitable that the function of your brain will decline as you get older? Or, do you believe that there are simple things you can do each day to preserve, protect and enhance it?

Feel Better Live More Bitesize is my weekly podcast for your mind, body, and heart. Each week I’ll be featuring inspirational stories and practical tips from some of my former guests.

Today’s clip is from episode 522 of the podcast with neurophysiologist and brain health researcher, Louisa Nicola.

Louisa believes that exercise is one of the most powerful tools we have to protect and enhance our brain health and, in this clip, she shares simple, practical strategies that we can all adopt – whatever our age or fitness level. 

Louisa believes that while modern lifestyles may contribute to cognitive decline, we have far more control over our brain health than we might think. Small daily choices add up, and it’s never too early—or too late—to start.

Thanks to our sponsor ⁠https://drinkag1.com/livemore⁠re⁠⁠

Show notes and the full podcast are available at https://drchatterjee.com/522

Support the podcast and enjoy Ad-Free episodes. Try FREE for 7 days on Apple Podcasts ⁠⁠https://apple.co/feelbetterlivemore⁠⁠

For other podcast platforms go to ⁠⁠https://fblm.supercast.com.

DISCLAIMER: The content in the podcast and on this webpage is not intended to constitute or be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or other qualified health care provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard on the podcast or on my website.

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