Dhru Purohit Show - Why You Need to Start Exercising to Grow Your Brain, Stave Off Alzheimer's, and Protect Your Heart

Episode Date: November 17, 2025

This episode is brought to you by Branch Basics, Masa Chips, and iRestore. Exercise is beneficial for your body, but it may be even more crucial for your brain. Today’s guest breaks down how movement fuels brain cell growth, protects against cognitive decline, and helps counter the effects of our overly sedentary modern lifestyles. Today on The Dhru Purohit Show, we’re revisiting one of our most talked-about moments with neurophysiologist Louisa Nicola to explore the latest science on movement, brain health, and cognitive decline. She shares how different types of movement help grow and strengthen neural connections, and why a sedentary lifestyle can be so damaging. Louisa also breaks down how beginners can approach movement safely and sustainably, as well as how aerobic exercise supports both brain and heart health. In this episode, Dhru and Louisa dive into: Why sitting too much skyrockets your Alzheimer’s risk (1:00) How exercise forges stronger, faster synaptic connections (3:00) Rethinking movement for brain health: a beginner’s roadmap (5:00) The sweet spot for daily steps and how it boosts your brain (13:21) The unique neurodegeneration risks women face (15:53) How aerobic exercise strengthens an aging heart (20:55) The wild science of how exercise can reshape your brain’s gray matter (25:25) Also mentioned: Full episode with Louisa Nicola  This episode is brought to you by Branch Basics, Masa Chips, and iRestore. Right now, Branch Basics is offering 15% off the Premium Starter Kit; just go to branchbasics.com and use the coupon code DHRU. Make 2025 your cleanest, healthiest year yet with Branch Basics! Ready to enjoy my favorite chips made with just three clean ingredients? Head to masachips.com/DHRU and use code DHRU for 25% off your first order.  Hair loss is frustrating. Give yourself the gift of hair confidence. For a limited time, my listeners get an exclusive discount on the iRestore Elite using the link irestore.com with code DHRU.  Sign up for Dhru’s Try This Newsletter Learn more about your ad choices. Visit megaphone.fm/adchoices

Hi everyone, Drew Brode here. We all know that exercise is good for the body. But when was the last time you really thought about how movement or lack of it is impacting your brain health? I'm talking about things like growing new brain cells, improving memory, boosting mood, and even reducing your risk of Alzheimer's disease. In today's episode, I'm exploring this topic in a segment with my conversation with Louisa Nicola. She's an Australian-born neurophysiologist and sports scientist who's made significant strides in the field of brain performance and human potential. In 2016, she founded neuroathletics, a consulting firm dedicated to optimizing brain health and performance for athletes, executives, and high performers from all across the world. And her innovative methods improve reaction times, decision making, and mental

acuity. All things we want, right? And one of the best ways to get it is to be stepping into the science of how movement is medicine for your brain. So let's dive into my featured section for my conversation with Louisa Nicola. Let's talk about the intersection of exercise or lack of exercise and the brain. I don't know many people that know as much about this topic and the combination of those two as you. We'll talk about your story in a second, but first, tell us why a sedentary lifestyle is so damaging for the brain, but also is so likely to increase your risk of getting Alzheimer's one day. The most powerful intervention that we have to slow the progression,

of these disease states is exercise. Exercise can be broken up into three categories. You've got resistance training, you've got aerobic training, and then you've got neurocognitive training. Aerobic training is absolutely fundamental for the brain and for this specific reason. It can help with the growth and proliferation of new neurons.

So you can literally grow new brain cells in your brain, in specific areas that are involved in the degeneration of or the accumulation of Alzheimer's disease. So you've got a little area in your brain. It's deep in the temporal lobes which sit behind the ears. It's called the hippocampus. It's a seahorse-shaped structure. That's where we hold all of our memories, memory formation, learning as well. And that's the first thing to shrink.

The structure of it shrinks, the volume size, and the neurons inside it. shrink. So evidently, when that shrinks, any part of the brain that shrinks and dies off, we lose aspects of what that controls. So that's why we lose our memory. But we've known now since 1960 to be exact, or the 1960s, that we can grow new neurons in the brain, which can help with better learning, better memory. We also know that through aerobic physical activity, I'm talking your long runs, your zone two cardio, we know that you can actually build greater connections. So your brain cells synapse with each other. They connect with one another to provide our thoughts and our actions. And we can now see that with more exercise, you can get more connections

between brain cells. So you can grow the cortex of your brain. We've known that since the 1960s because the first studies ever done were on mice where they, you know, they subjected mice to a little shoebox, one group, you know, which didn't have much activity, much light. It was a very dull environment. They weren't doing much movement. Then they put another set of mice in this Wonderland, if you will, where they had circuits. They had so many things going on. And over the course of six months, they saw that these mice actually grew the cortex, the outer

layer of the brain and they grew new connections in the frontal part of the brain. The frontal part drew is what is responsible for our executive functions, information processing speed, your ability to think, your ability to make sound decisions. These areas grow thickness-wise just through aerobic physical activity. Wow, that's incredible. So we've always known exercise is good. But what seems to be coming today in the research that you're going to be talking about, presenting and already have been presenting is that we're learning even more exactly the mechanisms of how exercise supports the brain. But also, the other side of that coin is we're learning that when we don't have that just how damaging it can be. If somebody is living a sedentary

lifestyle, which I think here in America, that's less than 4,000 steps a day, right? And a lot of people actually don't know, they're getting 4,000 or less steps a day. And they're not prioritizing some sort of movement, aerobic training, resistance training. How bad is that for their brain? All right, this holiday season, how about a wild idea? Give someone a gift that actually matters, health. You know, our homes are where we gather, recharge, and connect with the people that we love, hopefully. But there's a surprising truth. Many of the products that we use to clean our homes are quietly polluting the air we breathe. Most conventional cleaners are filled with harsh chemicals and synthetic fragrances that can irritate the skin, disrupt hormones, and even trigger respiratory

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Masa chips.com slash drew and use the code Drew for 25% off your first order. That's Masa M-A-C-H-I-S-A-chips, C-H-I-P-S-D-R-U, and use the code Drew for 25% off your first order. Absolutely detrimental. In fact, it's over 70% of U.S. adults don't meet the physical activity guidelines. The CDC states that we need to be doing at minimum, 150 minutes to 300 minutes. of moderate to rigorous physical activity per week. I think that there is a nomenclature mishap there because physical activity, a lot of people think, is doing the gardening. When I would lobby against that and say we should change the words to exercise, because exercise is going out

and stressing your body. You need a place stress upon a system in order for it to grow, and that's what you do when you exercise. So the mere fact that we are living this sedentary lifestyle, increasing the risk factors for Alzheimer's disease is detrimental. People think that, oh, I'm just going to exercise to look good. That's how I think we view exercise still. We don't go to the gym for our brain. We don't go to the gym for our heart. Most people are going to the gym or exercising just to look good. So if you've got that in your head, you may think, well, I kind of look good today. I don't really feel like working out. If you don't really understand how fundamental it is for the health of your brain and body

and how you actually live your life, like quality of life, you're probably going to be sedentary. You know, for a lot of my audience, especially on YouTube, that's in the 50 plus age group, 50 to 60, 60 to 70, and shout out to everybody who's listening, who's 70 and above. they maybe didn't grow up exercising. It wasn't part of their culture. They didn't have a dad or a mom or a family member. They're not used to it. And they're hearing about just how important exercises.

But then they hear the word gym. And there's a little bit of nervousness that's there. When it comes to tips to getting movement in, are there any things that you can recommend for people, right? anybody at any age group, especially with a little bit of training in the beginning, you can get into the gym and it doesn't have to be intimidating. But for the folks that are intimidated by it,

what other things can they be doing to get that movement in? This is not new information for me. I often refer to my parents who are late 60s. I gave my father, early 70s. They didn't grow up exercising, but now it's an actual family law now that they are exercising. And the way that I got them to start was just war. walking, just getting your steps in. And that's the first thing. You know, you don't want to shock your

brain. I know that you know a lot about dopamine. And dopamine is that molecule. It's that neuromodulator that gets released in pursuit of a goal. And if you set yourself up to achieve an unachievable goal, like going to the gym or going and doing a huge run, you're probably not going to achieve. And it's going to scare your brain. And you're probably not going to wake up and do it the next day. I want everyone to start really easy. You can get so much benefits from walking. I don't know why we've demonized walking. I consider walking one of the best exercises.

It's not the only thing we should be doing. But if you are completely sedentary only meeting three or four thousand steps a day, set yourself a goal of just doing a walk, an extra walk. Just walk. That's all you need to do to start. Then maybe that walk gets a bit faster. Maybe that walk turns into a jog. Maybe it's a full walk with a 10-minute

lung, walking lunges, if you will. Notice I didn't use the gym there or weights. Nothing is scary about walking. Even walking uphill. Even walking up a hill, exactly. You want to stress yourself just a little bit, but even getting steps in, the amount of benefits it does for your brain

and your cognition is, oh my God, it's unbelievable. I've heard a little bit about the origin of the 10,000 steps, it kind of was just like made up a little bit just as a benchmark for people, but is that still a good thing to shoot for? Especially because we know that a lot of people are living a sedentary lifestyle,

getting four to five thousand less or less steps a day. I think that we should be shooting for 12,500. Great. To be. Talk about why. I think so it comes down to just how much you are pumping blood throughout your body, right? The way that this actually affects brain health

actually comes from the heart. Because what we're doing is your brain is the most vascular rich organ in the entire body, meaning it's got so many blood vessels. You've got capillaries, which are these one cell thick blood vessels. You've got veins. And you've got these big arteries. And every single vessel feeds the brain with blood. And the moment that that little vessel dies off, you will lose blood supply to that.

neuron. That neuron isn't fed with oxygen and nutrients, which is what blood does. So therefore, it's got no use, so it'll die off. We've got around 87 billion neurons in the brain. And so if they start to die off over time, that's what we get with impairments in our cognition. So walking is just a way to just keep flowing blood throughout the body and to the brain. Because your capillary isn't there. We need to be using them. So, Every time you are pumping blood, you know, anything above your baseline. So right now we're probably, depending on how fit we both are, our resting heart rate, maybe in our 50s, right?

So we're pumping, we're doing 50 beats per minute. Whereas if you're just out there walking, you're probably reaching about 100, 110, 130. So you're getting more blood flow than if you were just sitting down. That's my take on the 12.5,000 steps per day. I love that. And you know, you have a fantastic quote. I don't know what order it's in, but what's good for the brain is good for the heart. What's good for the heart is good for the brain.

What's good for the heart is what's good for the brain. But I guess both are true, right? Like anything that you can do that's going to be supporting your brain health, generally speaking, those things are all good for the heart. Yeah. And but in the way that you're talking about it, really if you can prioritize your cardio training, just by a vigorous walk that's there or other things that are supportive and you start where you are and you build up further.

Sure, if you can work your way slowly up to resistance training, that's going to be helpful. But those things are going to be good for your heart, but they're also going to be super powerful for your brain. Connect the dots of why would that be that all this movement would be supporting either a delayed diagnosis of Alzheimer's disease or hopefully knock on wood, you know, not getting Alzheimer's disease in the way.

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Friday savings. That's happening all month long. And with the code Drew, D.HRU at I Restore.com, you can unlock an exclusive discount on the I Restore Elite. That's Drew, DHRU at irrestore.com. Please support our show and tell them we sent you. So let's actually take a bit of a physiology lesson, if we will. And I really want to go back to your previous comment about your viewership being in that 50 to 60 year old. Right on YouTube. Okay. On YouTube.

But that's really important because I actually have, as a woman, I have a strong relationship with the association between postmenopausal women and dementia. We know that two out of three cases of Alzheimer's disease is women, right? So we have to understand why that is and we have to understand the wrong. that estrogen plays, our dominant hormone. So if you are born a female with, if you are born with a uterus and ovaries, that's what I mean when I say female, you have more estrogen receptors in your brain. And evidently as we go through the women, go through the menopausal stages, varies in age, maybe it's around 52, I think that's the global average age,

you start to get less estrogen. We don't produce any more estrogen. Therefore, For estrogen is, if that is the most dominant hormone in the brain, we have a higher efficacy of getting these neurodegenerative diseases. So we need to understand, especially as females, just how important exercise really is for a healthy functioning brain, for a healthy brain in terms of function and structure. And I really think that females have been dramatically understudied. when it comes to these diseases in academic medicine. We won't go into that because I have beef with Charles Darwin.

So we won't go into that. But I really wanted to highlight that and the importance of ladies in their 50s, in their 60s, who are leading up to that stage, how fundamental exercise really is. Is it too aggressive to say that a sedentary lifestyle? It impacts everybody, regardless of your gender, but in particular because of our modern lifestyle,

A sedentary lifestyle is going to take its biggest toll on women. Is that too aggressive to say? That's not too aggressive at all. So that's a true statement. That's a true statement from me. It's an important thing to talk about because we want to protect everybody in society, but it's important for women to know how they might be more vulnerable because of their unique situation with hormones.

Yes. And when I said the statistic, two out of three, two out of three Alzheimer's cases are female, we still don't know why because women are understudied in science. So we need greater advocacy for understanding that. We need to understand why that is, but we do have a rudimentary understanding and it does come down to estrogen.

Yeah, there's a lot of really great researchers in that space that I'm sure you know, Lisa Mascone, other individuals that are doing some great work, but yes, we need more of it. So let's go back to the physiology lesson and we can understand why the heart plays a really important role. As we age, and this actually comes from Ben Levine,

who's a sports cardiologist, and he's done absolutely foundational work when it comes to the structure of the heart. So what happens, just like the brain, as we age, the brain changes, okay? It ages too. We see a decrease in our cell size, because as we age, like we get a decrease in cell size. It's just part of the natural brain aging process. You're never going to get to age 100 and see thicker cortical areas in your brain as opposed to a 20 year old. So we just know that. The heart ages too. So as we get older, we get stiffening of the arteries. You know, the arteries, those big pumps that come out of the aorta that pump your entire body of blood. They get stiffer as we age. What also happens is we have a left ventricle of the heart.

we've got a right ventricle. The right ventricle pumps blood to the lungs. The left pumps blood to your entire body, the organs, the muscles. That left ventricle over time gets stiffer. So we get something called left ventricular hypertrophy. So the walls of the left ventricle thicken as we age. Now, Ben Levine was really, he's wonderful. He did a study where he took 53, 50-year-olds. He subjected them over the course of two years to maximal aerobic exercise. I think it was around three to four hours per week. Maximal aerobic exercise is when you're pushing past your limits. You're huffing, you're puffing, you're going really hard. He pushed him to that zone. And he took, you know, he took images of the heart. He did echograms. He did every image of the heart to see the structures.

Over the two years, at the end of the two years, he rescanned the hearts of these 50-year-olds. And he found that he reversed the age-related changes in the heart by 20 years. Wow. So these 50-year-old hearts looked like 30-year-old hearts. Specifically, what he saw was that left ventricle. It actually, the walls got thinner. So the ventric got bigger, so he could allow more blood flow to come in. Therefore, more blood to the muscles and more blood to the brain.

And over how much of a period of time? That was over two years. And that was maximal. And we'll go into that as well because we haven't even touched on resistance training. But we know that you can change the structure of your heart. It's actually called cardiac remodeling. You can remodel your cardiac system. So what happens when we do that?

We get a stronger heart, a stronger foundation to pump blood through the aorta. Now, your aorta comes up and out of the aorta, we've got branching of two main sets of arteries. You've got the carotid arteries on both sides, obviously, and they supply the frontal part of your brain, the anterior part of the brain with blood. Then you've got the vertebral arteries. They supply the posterior aspect of your brain. So the better structured your heart, the better structured your aorta, the more blood will pump more efficiently to the brain. So two years of vigorous exercise led to an almost biological age reversal of the heart of 20 years.

I don't know anybody that wouldn't want that. Absolutely. So what does that mean? Let's go back to aerobic training. You can't just perform maximal exercise. That is just, that is silly. I would never get a 65-year-old who is completely sedentary to go from that to maximum X.

You don't go from zero to 100. Correct. That's why you want to walk. You want to set the foundations. Everything is done in levels. You set the foundations. You build up some angiogenesis, the creation of new, new blood vessels. You build up your muscles.

You build up your tolerance to CO2, right? Then what you want to do is you want to pick it up a notch. Maybe you jog. maybe you get on a bike, you go a bit harder, and then you build yourself up to be doing maximal aerobic exercise. That's fascinating. You know, another thing on the topic of exercise that you've been known to talk about, and in fact, I think it's one of your most viral clips.

You connect the dots between gray matter in the brain and exercise. Can you chat about that? And a lot of our audience, give them a refresher on what gray matter is, why it's so important. So we've got gray matter in the brain, and that sits on the brain. and that sits on the outer cortex, and they are the cell bodies of the neuron. So the neuron being the chief brain cell, the only electrically active brain cell, consists of a cell body, just like the cells in your body, and then you've got this axon that comes off it.

The axon has the myelin sheath, and that's where that's called the white matter. Okay, so that's the white matter of the brain, and that's where we have speed of thought. Okay, we call it conduction velocity in neurophitheatre. physiology. So that's where our myelinated neurons are. That's the white matter. The gray matter is the cell bodies. That sits on the outside. And we know now that around 70 to 80 percent of brain gray matter is modifiable by exercise. Modifiable. Now, the cell body has these little legs that come out. They're called dendrites. And those dendrites will stick to other dendrites of nearby my cells and when they connect, they create a synapse and electrical, electrical chemical

reaction that happens. And that's what produces our thoughts and our actions. But over time, those dendrites die off. But we can grow new dendrites. And that's what is responsible for greater cortical area and greater cortical mass. And we do that through exercise. So you get greater connections between. these cells. So more connections, therefore, speed of thought is happening, greater capacity to hear,

to learn, to remember, to tell yourself to go to sleep. All of this matters. So if you care about brain health, you have to care about exercise. If you care about your brain, you have to love exercise. Oh, I love that. And treat it like hygiene. Just the same as you brush your teeth. That's super powerful. Whether you're getting into movement or you've been active for years, I hope this segment has shifted or reframed how you think about exercise. If you like the conversation and you want to hear more, you can find a link to my full-length interview with Louisa Nicola in the episode show notes below. In the full-length episode, we talk about why sleep is so critical for preventing disease,

the connection between muscle and brain health, and Louisa shares the number one myth about Alzheimer's disease. I hope you check it out. And again, if you enjoyed today's episode, please take a moment to share it with a friend or loved one. Until next time, thanks for tuning in.