Overwhelmed with her graduate studies, Jennifer Heisz one day she borrowed a friend’s rusty racing bike and that changed the course of her career. She was studying cognitive neuroscience, but, dissatisfied with her work and personal life, she began to experience what she now recognizes as a “very severe anxiety”. Her friend suggested riding a bike to take a break and although she was not an athlete, she enthusiastically took up cycling and found that it “calmed the mind”.
That discovery convinced her to change the focus of her research. Today, as director of the NeuroFit Laboratory at McMaster University in Hamilton, Ontario, Canada, studies the interplay between 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 very pervasive and fascinating,” says Heisz. That idea is central to his new book, Move the Body, Heal the Mind, detailing the latest science behind exercise and mental health, as well as his own journey from inactivity and serial emotional crashes to triathlon training and increased composure. I recently caught up with Heisz to discuss his book and to discuss mental health, the benefits of light exercise, the stresses of the pandemic years, and choosing the right activity right now to lift your spirits. This is our conversation.
Can we talk regarding exercise and the anxiety that many of us are currently feeling?
JH: Exercise is extremely beneficial in reducing anxiety. In fact, at the end of each workout, you typically get a brief relief from anxiety, due to the neuropeptide that increases with exercise. It is a resistance factor. Helps calm the anxious amygdala, the part of the brain that recognizes danger and puts us on high alert. For the last few years, with the pandemic, our amygdala has been hyper-alert, triggering a near-constant stress response. This chronicity of stress starts to make our minds really fearful and you end up with constant anxiety by increasing levels of the neuropeptide. Exercise helps calm the anxious amygdala, reduces fear and hypervigilance, and keeps us calmer.
Any type of exercise in particular?
JH: The really positive thing is that mild to moderate exercise, such as walking, is enough. Research from my lab shows that this type of exercise reduces anxiety immediately following training and then over time, if you continue to exercise, it reduces anxiety further and for longer. Doing 30 minutes of this type of exercise, three times a week, is good. Walk, bike, swim, dance…a wide variety of activities work.
What regarding the most intense workouts?
JH: You have to be careful with really intense exercise and anxiety. If you feel anxiety, you are already under stress. High-intensity exercise is also a type of stress, and our bodies generally only have one response. During intense exercise, you add extreme physical stress to what your body is already feeling, and all of that might be too much. Just before the pandemic, I was training for a triathlon and doing a lot of high-intensity exercises. But once the pandemic started, I felt so much emotional stress that I mightn’t finish those workouts. So, I backed off. What I would tell people is that when you’re already feeling stressed, prolonged intense exercise may not be the right choice.
What would you recommend people do instead?
JH: Try to do exercise that feels comfortable and challenging, so that your heart rate looks elevated but not accelerated. For many people, that would mean taking a brisk walk around the park or around the block.
Does exercise help in the same way once morest depression?
JH: Traditionally, depression is attributed to a lack of serotonin in the brain, which is treated with antidepressants. However, for some people with depression, medications don’t work well, probably because serotonin isn’t their problem. Many of us who study depression now think that the problem may be related to inflammation, which is related to stress. It begins to damage cells in the body, inducing an immune response and increasing inflammation, which can then travel to the brain and affect mood. For those people, exercise can be the medicine they need, because it helps fight inflammation. In studies, when people who haven’t responded to antidepressants start exercising, they usually see significant reductions in their symptoms.
How much exercise are we talking regarding?
JH: A study looking at how often, or how much, exercise you need to fight depression compared 150 minutes of moderate to vigorous exercise a week, the standard exercise recommendation for physical health, with a fourth part of it. And both groups benefited equally. Therefore, it seems that exercise prescription for mental health is lower than for physical health, which is good.
In terms of potentially helping to combat depression, do you think the intensity of the exercise is important?
JH: Maybe yes. A few years ago we conducted a study with healthy students facing high-pressure final exams. Some of them moderately rode stationary bikes three times a week for 30 minutes, and others did shorter, more intense interval cycles. A third group did no exercise at all. After six weeks, the students who hadn’t exercised showed signs of fairly severe depression., which had appeared surprisingly quickly, and presumably because of his academic stress. However, the students who had exercised moderately were less stressed than at the start of the study and had lower levels of inflammation. But what I find really interesting is that those who did 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 honestly in your book regarding your episodes of anxiety, stress, and obsessive-compulsive disorder, even following the birth of your daughter and, later, your divorce. Did exercise help you cope?
JH: It’s the key. Mental illness can happen to anyone Even people who seem to be handling things 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 he knew how powerful exercise is, as a stimulus, to alter the brain. Someone mentioned triathlons. He was still riding a bike at the time. So, I added activities like running and swimming.
And did you qualify for the world championship?
JH: Over time, yes. But it took me years. Then the championships were delayed due to the pandemic and now I am out of shape and will have to start training once more. But that’s something to look forward to, really. What I find is that, at times like this, there is comfort in exercise. In the peace we feel following a workout, hope is alive. You feel like the world is okay once more. And that is really special.