Recent science has found that consistent exercise can change the underlying structure of some brain regions. Photo / Isabelle Zhao, The New York Times
Decades of research have established that movement has a positive effect on mental health.
When it comes to mental health, most treatments for conditions like depression or anxiety come with caveats. Medications work for some symptoms, but can exacerbate others. Cognitive behavioural therapy is effective for many patients, but not all.
But there’s one strategy that seems to work for most people and almost all experts endorse, and that’s regular exercise.
Decades of research have established that exercise has a positive effect on mental health. In studies of patients with mild to moderate depression, for example, a wide range of exercise regimens has been shown to be as effective as medications like SSRIs (though the best results generally involve a combination of the two).
Moving regularly can improve sleep and reduce stress. While there’s good evidence for the mental health benefits of exercising for about 45 minutes, three to five times per week, even just a few minutes of walking around the block can have positive effects.
“Is this walk going to do anything?” said Jennifer Heisz, an associate professor at McMaster University in Canada and the author of “Move the Body, Heal the Mind.” “Yes! The answer is yes. It’ll do way more than you think.”
It’s hard to find a brain process that doesn’t improve with regular movement. Exercise boosts blood flow, decreases inflammation and improves brain plasticity. It also triggers the release of many mood-boosting chemicals, including beta-endorphins and cannabinoids (which both play a role in the “runner’s high” feeling), norepinephrine, dopamine and serotonin.
More recent science has found that, consistent exercise can change the underlying structure of some brain regions.
“You’re increasing actually the birth of new neurons within the brain,” said Mazen Kheirbek, a psychiatry professor at the UCSF Weill Institute for Neurosciences. By creating new brain cells, exercise “changes, over many days, how your brain functions”.
Adults typically don’t generate many new neurons, and it only happens in a few places, namely in the hippocampus, which is tied to mood and memory. People suffering for long periods from depression or stress tend to have smaller hippocampi than others, with fewer new neurons and less plasticity.
According to research on both humans and lab animals, there’s essentially a reverse effect – more neurons and a greater ability to adapt – after regular exercise, Kheirbek said. This is especially clear in people with more severe anxiety or depression, who generally see larger improvements over time.
Scientists haven’t yet determined whether, say, running is better than weightlifting for improving mental health.
For one thing, a lot of exercise studies are performed on animals, and it’s much easier to get a mouse to run in a wheel than lift weights, said Brett R. Gordon, a postdoctoral fellow at the Penn State Cancer Institute.
It is also hard to compare different kinds of exercise because the effects can be different for different people, and participants bring their own biases about exercise to a study. Someone who already enjoys running may be more likely to experience a mood lift after other forms of cardio.
However, there is some evidence suggesting that activities like yoga or tai chi are better for relieving symptoms of anxiety than, say, boxing or basketball. This may be because these fluid, low-intensity workouts often employ meditative or mindful techniques that have repeatedly proven beneficial for mental health.
“The mind-body connection, it can be present in all forms of exercise, but it’s reinforced very much in yoga and tai chi,” Heisz said.
More intense exercise – almost by definition – increases stress levels. Some of Heisz’s research suggests that people who report more symptoms of anxiety tend to see fewer mental health benefits from intense workouts in the short term than those with little or no anxiety.
But several experts, including Heisz, pointed out that over time, regular intense exercise can still have significant benefits to people with anxiety, if they stick with it and listen to their bodies. In fact, a large 2023 review suggested that HIIT workouts can be more effective at alleviating depression and anxiety symptoms than lower-intensity workouts.
But none of this matters if a patient doesn’t feel motivated to do it, said A’Naja Newsome, a physical activity researcher at the University of Central Florida. With depression in particular, she said, it can be difficult to get started, or to enjoy it.
“When you think about someone who is experiencing depressive symptoms, it’s often lack of interest, lack of energy, lack of mood,” she said.
She stressed the importance of beginning with easier, lower-impact activities and having an exercise community or workout buddy to keep you going. And if you’re just starting out, a daily walk might be more sustainable than an intense workout.
“While I’m a huge proponent of resistance training and aerobic exercise,” she said, “if someone doesn’t like it, they don’t enjoy it, they’re not going to do it.”
This article originally appeared in The New York Times.
Written by: Erik Vance
Photographs by: Isabelle Zhao
©2025 THE NEW YORK TIMES