Why Your Brain Hates Exercise, with Jennifer Heisz (S3, Ep 6)

We all know exercising is good for us – it reduces anxiety and inflammation, boosts the immune system, and may even ward off dementia, all while it helps keep us fit. But our brains don’t want us to do it! Meet Dr. Jennifer Heisz, a neuroscientist who learned how overcome the brain’s resistance and used exercise to conquer depression – and complete a triathlon! Plus… why those who fear exercise the most have the most to gain from it. 

Phil Stieg: Hello.  I’d like to welcome Professor Jennifer Heisz, award-winning neuroscientist from McMaster University in Hamilton Ontario, and an evangelist for the positive benefits of exercise on brain health. Her recent book, “Move the Body, Heal the Mind” explores exercise and its benefits in dealing with depression, anxiety, addictions, sleep disorders, and even slowing dementia. And as a side benefit, how it enhances your focus and can boost your creativity.
Dr. Heisz, thank you for being with us today.

Jennifer Heisz: It’s my pleasure to be here.

Phil Stieg: So in reading through your book, that’s how I spent my past weekend. Move the Body, Heal the Mind, one can’t help but note how this seems to represent both a personal saga and also your life as a neuroscientist. Can you expound on that a little bit?

Jennifer Heisz: That’s right. I did come into this research on a personal journey. In my graduate school, I was studying very fundamental questions about the brain, and it became very apparent to me that something wasn’t quite right with my own brain. So I sought some help but wasn’t really getting it from the traditional medical community. And so on a whim, I borrowed a friend’s rusty old road bike. And those bike rides really soothed my mind. They got me through the stress of graduate school. And from that point forward, I really did shift my whole focus of research onto the benefits of exercise for the brain.

Phil Stieg: Just so everybody understands when you say something wasn’t right with my brain, it’s not like you had a DSM category thing, which is the psychiatric handbook, but you had the problems that everybody else has, some anxiety, maybe some eating disorder issues and a little bit of depression. So, everything that we all face on a day-to-day basis. And again, it seems to me that you got onto that bike, but then you also have gone to extremes. You’re competing in triathlons. Can you clarify for me what should mere mortals like me do?

Jennifer Heisz: Yeah. Well, I’ll preface this by saying I have never been an athlete. And so, yes, this Triathlon business was a new venture for me, and it did give me something to focus on during sort of a difficult transition in my own personal life. But no, the benefits of exercise are so beautiful, you can get them with just a walk. A walk a day is something a lot of people do anyways. And this gives them tremendous benefits for both their body and their brain.

Phil Stieg: I was fascinated by your first chapter because I have to admit, probably I’m a bit older than you. I’ve experienced this one too many times. Every time I’m going to get in shape.  And I’ve started so many times. And your explanation made me feel better about myself, about how the brain shuts you down and stops you from continuing exercise. Can you explain that to us all?

Jennifer Heisz: Yeah. I think this is such an important message, that the brain is actually hardwired to conserve energy. And so by virtue of that, it makes us lazy. And so we’re not lazy people, but the brain wants to conserve energy in any voluntary movement just for fun or for health the brain sees as an extravagant expense, and it doesn’t want to have it. And so it goes out of its way to protest, you’re too tired. Do you even have time? And so this can really derail even our best intentions.

Phil Stieg: So that kind of implies that there’s an integration between the metabolic center of the brain, the hypothalamus, and also that emotional cognitive component that talks you out of going out there and exercising.

Jennifer Heisz: Absolutely. The brain is so interconnected, and the brain and the body communicate so much, much more than many people realize, especially centers like the amygdala, which is our threat detection and fear that talks directly to our hypothalamus, which then can send shockwaves through the body in the form of stress.

Phil Stieg: You have a myriad of examples throughout the book, and I want to get into some of them. But before we start doing that, can you kind of give a 10,000 foot overview of why exercise is good for the brain from a neurochemical and an anti-inflammatory standpoint?

Jennifer Heisz: The brain relies on the body moving. And when we move our muscles, neurochemicals are released from the muscles into the bloodstream, and they travel all the way to the brain, giving the brain what it needs to thrive. And these are the nutrients the brain needs to thrive. So without movement, we’re not getting those. We’re not getting things like growth factors that support the growth and function of brain cells. We’re not getting dopamine that gives our brain the reward it needs to feel good. We’re not getting the serotonin regulation that we need to ward off things like dementia or depression and to keep us calm under stressful situations.

Phil Stieg: In the book, you provide excellent guides to what are appropriate exercises. Just in thinking about it, is there a time period that somebody should walk? Is there a heart rate that they should try to achieve? What do you propose?

Jennifer Heisz: I guess it depends on where they’re starting and what they want to achieve. So for many people who aren’t moving that much or haven’t been moving that much lately, any movement counts, some is better than none. And that, I think, is a very good goal to achieve. However, if you’re regularly walking and you want to improve your brain health and ward off dementia, I recommend trying interval walking. And so interval walking is your regular walk, but intermittently, you’re picking up the pace. So between light posts, you’re adding a few hills, and basically you want to pick up your pace to the point where it’s difficult to talk, so you can’t really have a conversation, and that’s when you know you’re walking fast enough to get the benefits.

Phil Stieg: Yeah. So your book is chock full with how exercise is good for certain things, and I’d like to touch on a few of them. And the ones that I’ve picked are the ones that we all experienced pretty much on a day-to-day basis. So this is a good “make yourself feel better situation”. Let’s talk about anxiety. Why is running better for you in regard to anxiety?

Jennifer Heisz: So anxiety is actually just the brain’s natural response to stressors. And it can be good. It can alert our brain, get us focused on the problem at hand, and help us solve it. The problem becomes when anxiety goes from zero to 100 and it gets ahead of us and takes over. And this fear starts manifesting as, like racing heart, difficulty breathing, difficulty thinking. And so the beautiful thing about exercise is that you can use it to expose yourself in a controlled manner to these symptoms. So you get essentially habituated or used to them, and you can tolerate them more so that when your heart starts to race during exercise, you can be like, okay, I’m just going to allow it to race and stop. You have full control over that situation, and then you learn oh, well, I have that same control over the situation when I’m not exercising, but when I’m experiencing a stressor. And so it allows people to be less reactive to a stress, it essentially tones the stress system.

Phil Stieg: I found it interesting how you related this to I guess you had just had a child and you’re still a graduate student or you’re working whatever. And the stress of marriage, graduate studies and all this really got to you and was creating incredible anxiety.  What was the insight that you think you can relate to people? What made you realize, wait a minute, this is all anxiety. Now I’m going to go start trying to get help. And also the fact that you tried to get help and you got drugs and that didn’t work relay that story.

Jennifer Heisz: Yeah. I think it’s difficult when you’re in the throes of it to really recognize what’s going on because it’s such a funny puzzle, because you’re trying to think your way out of a problem with your thinking. And so the beautiful thing about exercise is it gets you out of your head and into your body.  Once I started these bike rides, it was just amazing. I had so much peace and so much calm that I hadn’t for years, and I just couldn’t get enough of that feeling. And eventually you associate that feel-good feeling with the ride, and it’s something that you just need.

Exercise has this incredible anti-inflammatory effect which protects it against chronic stress. And when we’re under chronic stress, it affects the immune system. The immune system becomes overreactive. And that’s not a good thing. And that extra inflammation in the body moves into the brain and it starts to create symptoms that look a lot like depression and anxiety. And so the nice thing about exercise is that it’s anti-inflammatory. So an acute bout. It causes a little bit of inflammation at first. But once you stop exercising just after your first workout, it sends in this anti-inflammatory crew that cleans up all that inflammation created by exercise and then some. And so you end up being less inflamed. And the more you come back to exercise over time, the less and less inflamed you become.  All that regulation of the immune system helps regulate the mind and your back to thinking clearly and feeling better.

Phil Stieg: I was actually somewhat surprised to learn that, what, one third of the population that started taking serotonin and reuptake inhibitors, Prozac or Zoloft for depression are non-responders. 

Jennifer Heisz: Yeah. It is surprising that one in three people don’t respond to antidepressants, and there’s really no conversation to patients about this from the doctor. So it can be really frustrating. As you can imagine, you show up to the doctor’s office finally getting the courage to seek the help you need. You get the medication, and it doesn’t work, and you go back, you get a new medication, it still doesn’t work. And the problem is that the assumption is that all forms of depression come from the same source, which is a lack of serotonin in the brain. But this is not true. This is not true. And so when we give drugs that treat that low serotonin, it doesn’t work because that’s not the problem for them. They already have enough serotonin in their brain. The problem is something else, and often that something else is related to stress. Stress reactivity that stimulates the immune system, causes extra inflammation in the body that infiltrates the brain and starts to create these symptoms.

Phil Stieg: You talk a lot about the immune system hyperdrive that kind of kicks in as a result of stress. On this show, we keep emphasizing that stress is bad, and I think in America, that’s hard to avoid, but it is bad. So talk about the immune system hyperdrive and how running really helps shut that down.

Jennifer Heisz: Yeah. And maybe I’ll have a sort of a caveat around “stress is bad”. In fact, stress is inevitable, as you mentioned, is part of our life, but it really is in our reaction to stress that makes it so dangerous. So it’s that getting really angry, getting really tense when things don’t go as expected or as planned, and sort of trying to keep a more even keel. So this is one way that exercise is extremely beneficial is that it helps you regulate your response to stress. So you’re less moody, less up and down, and you keep much more of an even keel.

Phil Stieg: I also found it fascinating how you describe the benefit of hard workouts. So you really get that lactate release in your muscles and it really hurts. But in a sense, you describe that as being beneficial because once that gets up into the certain parts of your brain, it stimulates new nerve cells. Describe that for us.

Jennifer Heisz: Yeah. So, this is one of the most interesting findings. Lactate, which if you’ve ever been to a spinning class or a workout class, the fitness instructor is always saying, okay, we got to flush out that lactate, get rid of that bad stuff. And it turns out lactate is actually one of the greatest promoters of neuroplasticity. It moves directly from the muscles to the brain into a region called the hippocampus, which is important for memory. It’s damaged by Alzheimer’s disease, but it’s also one of the regions in the brain that can birth new brain cells throughout our lifetime, even into older age. And so by giving the hippocampus lactate, it can grow stronger and fortify against dementia.

Phil Stieg: So it keeps you forever young, right?

Jennifer Heisz: Forever young in heart and mind.

Phil Stieg: I wanted to touch on that next. You describe various workouts in your book, which I think are excellent. Let’s face it, an 80-year-old shouldn’t be trying to do what a 25-year-old should be doing. So is it exercise in general or actually, are there specific exercises for specific effects? And then finally, what’s the age-appropriate exercise?

Jennifer Heisz: It is very personal, and maybe it’s not necessarily age appropriate, but like “ability appropriate” or “fitness appropriate”. I know lots of older people who are much fitter than any 20-year-old. And so it does come back to your own personal exercise tolerance, which can be independent of age in fact.

I do have these specific workouts at the back of each chapter. It can be difficult to prescribe exercise for somebody who’s anxious because a lot of the time people who are experiencing symptoms of anxiety are also anxiety sensitive, meaning that they have this fear of the symptoms of fear itself so a fear of fear itself so when their heart starts racing they think they’re having a heart attack, when they’re hyperventilating they think they’re going to suffocate or when they can’t think they think they’re losing their mind and so for these individuals often they don’t like exercising and they certainly don’t like doing it intensely but the kicker is that these individuals stand to benefit the most.  One way that we can slowly, gradually safely introduce exercise into their life is almost like a way of exposure therapy.  I have the fear Buster workout, where we a few seconds at a time start introducing exercise and just quick sprints so that they can feel their heart racing, they can feel their breath rushing in and out and get used to those symptoms almost like an exposure – as a habituation to those symptoms so that they lose their power over them and they’re not as scary.

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NarratorMany of us have faced the challenge of our brain’s natural resistance to exercise.  In this edition of “This Is Your Brain, The Guided Tour”  we look at how one company has found an answer to this problem by making exercise … addictive! 

Think of a compelling social media platform – display it on a giant, high definition touchscreen, and then bolt that screen to the front of a sleek (and fabulously expensive) exercise bike.  You have just recreated the Peloton – the most successful exercise product of the last decade.  

The founders of Peloton have described how they looked to the addictive experiences of video games, binge-watching Netflix or shopping on Amazon in designing their company.  

Riding a Peloton bike is a convincing internet simulation of a social experience.  On-line “users” are organized into virtual “classes” where they can video chat with other Peloton friends while being urged to pedal faster by impossibly good-looking virtual instructors.  

The sense of competition is enhanced by constant feedback data on each user’s heart rate, distance covered and watts of energy generated being continuously displayed  on a leaderboard which ranks them against a world-wide network of more than two million users.  Users can click  on the leaderboard to provide virtual “high-fives” to each other for a job well done.  

Like all successful video games, each little “victory” stimulates a tiny dopamine “hit” in the user’s brain – turning the Peloton ride into an addictive habit.

This simulated sense of community is Peloton’s primary product.  They describe themselves as an interactive media company – that just happens to sell exercise equipment.  In the summer of 2020 the global pandemic began to isolate people in their homes.  This created a hunger for any form of communal activity, and Peloton sales jumped an astounding 172% in six months!

With a starting price of  two thousand dollars – not to mention the logo emblazoned shoes, workout gear and the forty dollar a month membership fees –  Peloton has managed to engineer an online experience that is as expensive as it is addictive.

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Phil Stieg: Exercise doesn’t always have to  be exhausting to be good for you.  Can you talk a little bit about the benefits of high versus low impact exercise?

Jennifer Heisz: Yeah, absolutely. I think the benefits of walking are tremendous, and that shouldn’t be understated. A walk a day, an interval walk a day keeps dementia at bay. I like to say that and it’s true. I would say for most people, the focus should be on consistency rather than intensity, and keep coming back to something that you enjoy to do. But always have an eye to move a little more every day.

Phil Stieg: In the book, you kind of emphasize basically 30 minutes, five times a week. Is that a reasonable goal, you think?

Jennifer Heisz: There are guidelines for physical health, which are weekly, 150 minutes per week of moderate, like a brisk walk. Or you could get by with less vigor. So it’s 75 minutes of vigorous activity. Those are based on studies done for physical health. You can get by with less for your brain. The brain doesn’t need as much as the muscles of the body. My goal is to just get people moving so some is better than none. And I think the problem, especially nowadays, is we’re sitting so much, and that’s the problem. And so breaking up sedentary time is so key. When we sit for too long, blood flow to the brain decreases, and you can’t think well, you don’t feel well, it’s more difficult to sleep. And so breaking up these times is really beneficial.

Phil Stieg: Just personal story from my side is like when I am out exercising and on those rare occasions when I’m actually really pushing myself and it starts to hurt, I find that just finding my breath and saying, wait a minute, my breathing rhythm is off – that not only helps my body feel better, but also helps my mind feel better. Is that something that you’ve experienced as well?

Jennifer Heisz: Absolutely. And through the breath is a great way that we can gain control of our mind and our body. Your mind, it really only has one track. It can only think about one thing at a time. And if you’re thinking about your breath, it   can’t think about how much pain you’re in or the anguish you’re feeling or the panic or the nervousness. It’s the breath – and that’s so grounding and centering. And the amazing thing is that when we control our breath, we slow down the nervous system. We trigger the autonomic nervous system – that rest or digest – and it sort of triggers us into a calmer state of being.

Phil Stieg: Aside from the fact that our brain is telling us, don’t exercise because you’re consuming too many calories and taking it away from the brain, what do you have to say to people in our society now that they’re stuck on their iPhone, they’re stuck on their desktop, creating stress by being on that, but also forcing them to sit in a chair and really do nothing? What commonsensical thing do you advise to your clients when they come to the NeuroFIT lab. 

Jennifer Heisz: Every 30 minutes, stand up and take a two-minute movement break. That’s incredibly beneficial for increasing blood flow to the brain. It’s so simple, too. Right?

Phil Stieg: Next time I’m in the middle of a craniotomy, I want to stand up.

Jennifer Heisz: Or you could exercise before your craniotomy. The benefits of exercise linger for a long time after each workout.

Phil Stieg: So I’m curious. I mean, this is a major accomplishment. It’s a real treatise on the benefits. And I can see where your lab is going to go with this and all the activity. But what’s next for you? What’s your next amazing thing that you’re going to try to achieve?

Jennifer Heisz: You know what? I haven’t figured it out yet. I poured my whole heart and soul my whole life into writing this book. It has my research, my personal story. It was a real journey for me. And so after you do something so major in your life, I’m just taking a pause to just reflect and enjoy the process before jumping into something next.

Phil Stieg: Yeah. Was it difficult for you to open up and reveal yourself, or did you feel that that was the best way to relay how important this is? It’s important to you. It should be important to everybody.

Jennifer Heisz: Oh, my God, it’s so hard. It’s still hard to talk about my own personal struggles. But I knew that it would really give credence to the science. I was talking about.  I know what it’s like. I’ve experienced it personally. And I’m not just talking at them, I’m talking to them as someone who has experienced this before and has succeeded in learning to manage my own mental health issues.

Phil Stieg: It’s not that I’m not telling people that they shouldn’t use antidepressants, but I think the thing that I found so hopeful from you is that, listen, you might feel a little bit depressed, try something commonsensical like exercise, and it may be of benefit to you and you can avoid all these other things.

Jennifer Heisz: Yeah. And I completely agree with you. I wouldn’t want to say don’t try antidepressants, don’t use them because those are so helpful for so many people, not at one or the other. It’s just this other thing that we can do to better our health.

Phil StiegJennifer Heisz, it’s been delightful to meet you and have this opportunity to talk about your book “move the body, heal the mind”.  I found the book enlightening and uplifting.  It will, I hope, help me focus and get over the hump of being able to exercise consistently. You are a credit to the neuroscience community and I wish you all success with the publication of your new book.

Jennifer Heisz: Oh, thank you very much.