Can moving the body help reduce anxiety? With light exercise, yes

When Jennifer Heisz was in grad school, she borrowed a friend’s old, rusty bicycle and ended up redirecting her career. At the time, she was studying cognitive neuroscience, but dissatisfied with the direction of her work and personal life, she began to experience what she now recognizes as “very severe anxiety,” as she recently told me. A friend of hers then suggested riding a bike to relieve her symptoms. Once not a sportsman, she started pedaling with enthusiasm, and found it “calmed my mind”, as she said.

This discovery convinced Heisz to change the focus of his research. Now director of the NeuroFit Lab at McMaster University in Hamilton, Ontario (Canada), she studies the interaction of physical and emotional health, and how exercise helps prevent or treat depression, anxiety, stress and other mental health conditions.

“The effects of movement on the mind are vast and fascinating,” said Dr. Heisz.

That idea animates her new book, “Move the Body, Heal the Mind,” which chronicles the latest science on exercise and mental health in detail, as well as the author’s journey inactivity and emotional crises in series to triathlon training and increased tranquility.

I recently spoke with Dr. Heisz to talk about his book and what it can tell us about mental health, the benefits of light exercise, the stresses of the pandemic years, and how to choose the right workout right now to lift your spirits. Below is our conversation, edited.



Can we talk about exercise and anxiety, which many people feel these days? Exercise is extremely beneficial for reducing anxiety. At the end of each workout, in fact, you typically get a brief relief from anxiety, due to neuropeptide Y, which increases with exercise. It is a resilience factor. It helps calm the amygdala, which is the part of the brain that recognizes danger and puts us on high alert. In recent years, with the pandemic, our amygdala has been anxious, on hyperalert, triggering an almost constant reaction to stress.

This chronicity of stress starts to make our minds really scared, and you end up with constant anxiety. Exercise, by regulating neuropeptide Y, helps to calm the amygdala, decrease fear and hypervigilance, and keep us calmer.

Any specific type of exercise? The cool thing is that light to moderate exercises, like walking, are enough. Research from my lab shows that this type of exercise reduces anxiety immediately after your workout, and over time, if you keep exercising, it reduces anxiety even more and for longer. It seems that about 30 minutes of this type of exercise three times a week is enough. Walking, biking, swimming, dancing – a wide variety of activities work.

What about more intense workouts? You need to be careful with very intense exercise and anxiety. If you’re feeling anxious, you’re already under stress. High-intensity exercise is also a type of stress. But our bodies generally only have one stress response. So during intense exercise, you add extreme physical stress to the stress your body is already feeling, and it can all be too much. Right before the pandemic, I was training for a triathlon and doing a lot of high-intensity workouts. But as soon as the pandemic started I was feeling so much emotional stress that I couldn’t finish these workouts. So I backed off. What I would tell people is that when you’re already feeling stressed, prolonged, intense exercise might not be the right option.

What do you recommend people do? Aim to do exercises that feel comfortably challenging, so your heart rate is elevated but not accelerated. For many people, that means a quick walk around the park or around the block.

Does exercise help in the same way against depression? Classically, depression has been attributed to a lack of serotonin in the brain, which antidepressants treat. But for some people with depression, drugs don’t work well, probably because serotonin isn’t their problem. Many depression scholars now think the problem may involve inflammation, which is linked to stress. Inflammation starts to damage the body’s cells, inducing an immune response and increasing inflammation, which can then enter the brain, affecting mood. For these people, exercise may be the medicine they need as it helps fight inflammation. In studies, when individuals who do not respond to antidepressants begin exercising, they often experience significant reductions in symptoms.

How much exercise are we talking about? A study looking at how often, or how much, exercise someone needs to fight depression compared 150 minutes of moderate to vigorous exercise a week, which is the standard exercise recommendation for physical health, to a quarter of that. And both groups benefited equally. So it seems that exercise prescription for mental health is lower than exercise prescription for physical health, which is pretty cool.

In terms of potentially helping to fight depression, do you think exercise intensity matters? It might be. We conducted a study a few years ago with healthy students who were facing final exams with high pressure. Some of them rode a stationary bike moderately three times a week for 30 minutes and others did shorter, more intense interval cycling. A third group did not exercise.

After six weeks, the students who hadn’t exercised showed quite severe symptoms of depression, which came on with shocking rapidity and, presumably, due to academic stress. Students who exercised moderately, however, were less stressed than at the start of the study, and their bodies’ levels of inflammation were lower. But what’s really interesting to me is that intense exercise showed symptoms of increased stress, both physical and mental. So it seems that moderate exercise may be the most beneficial for mental health.

You speak frankly in your book about your own bouts of anxiety, stress, and obsessive-compulsive disorder, including after the birth of your daughter and, later, your divorce. Did the exercise help you deal with it? It’s the key. Mental illness can affect anyone, even those who seem to be coping well. For me and many others, life transitions like divorce and childbirth can be especially challenging. After my divorce, I really needed something to redirect my life. And I knew that exercise, as a stimulus, alters the brain in powerful ways. Someone mentioned triathlon. I was still cycling at the time. So I added running and swimming.

And qualified for the World Championship. After all, yes. But it took years. Then the championships were postponed by the pandemic and now I’m out of shape and I’ll have to start training all over again. But that’s something to be expected, really. What I think is that, in times like these, there is relief in exercise. In moments of peace after a workout, hope is alive. You feel like the world is right again. And this is really special.