There is a lot of scientific research showing how regular exercise can have a positive effect on one’s physical health, but its effect on mental health is relatively unclear. A study recently published in the British medical journal The Lancet sought to change that.
Dr. Adam Chekroud, assistant professor of psychiatry at Yale School of Medicine, and other researchers published a study in The Lancet Psychiatry that examines the association between physical exercise and mental health.
Chekroud said most prior studies that investigated this subject had a small sample size, which made it hard to make reliable conclusions based on the results. That is why his study looked at data from over 1.2 million people.
“It’s always important that we try and get as generalizable a finding as possible, and so, one risk of small studies is that you don’t have a very representative group of people,” Chekroud said. “You never know if your results are being driven by idiosyncrasies between all groups of people that you’ve brought in.”
The study tried to control for numerous factors, including age, gender, education, income and physical health. Chekroud said having over 1.2 million sets of data helped that process.
“There’s loads of things you need to control for,” Chekroud said. “The nice thing about having such a large sample size is that you can use statistical techniques to do that kind of control.”
Once the other factors were ruled out, the results of the study showed that people who exercised had about 40 percent better mental health than those who did not exercise. Within that group, those who exercised a moderate amount -- three to five times per week for 30-60-minute sessions -- had the best mental health.
“There was definitely an indicator of this 'Goldilocks effect,'” Chekroud said. “It seems like people in that middle range generally had the best mental health.”
That sweet spot, Chekroud said, comes pretty close to the World Health Organization’s recommendation of 120 minutes of moderate exercise per week.
The study did not control how the subjects exercised, but it did find that those who participated in team sports had the best mental health, about 25 percent more than non-exercisers. Aerobic exercise, like running and biking, also rated highly. But Chekroud said even low-intensity exercisers fared better mentally than non-exercisers.
These results, Chekroud said, are encouraging because it means better mental health is an attainable reality.
“It seems like these benefits may be within reach for a lot of people,” Chekroud said. “Beyond that, there also may be ways that we can optimize the kind of exercise that we do to improve our mental health even more.”