Plenty of research has shown how cardio is the closest thing to a miracle drug we have for improving our health and mood. But studies are increasingly finding that more exercise is not always better. For example, when cycling, swimming, and walking, you might see the most benefits for your brain and body by keeping your session under an hour .
A new study, published in The Lancet Psychiatry, supports this theory. It’s well established in the research that exercise can improve our mental health, and maybe even prevent depression. But the new study aimed to find out if there was an ideal amount to see the most benefits.
The researchers from Yale University looked at data from 1.2 million people, from 50 states, who completed the Behavioural Risk Factor Surveillance System survey in 2011, 2013, and 2015. The survey included information about physical health, mental health, and lifestyle, but the only mental health disorder taken into account was depression.
Team sports, cycling, aerobics, and the gym are best
Results showed that on average, participants experienced 3.4 days of poor mental health every month. Those who exercised had one and a half fewer days of poor mental health than those who didn’t — and exercising for 45 minutes three to five times a week showed the biggest benefits.
Team sports, cycling, and doing aerobics and gym exercises were associated with the biggest reductions in mental health problems (22.3%, 21.6%, and 20.1%, respectively), but even household chores showed an improvement of 10% (about half a day less each month.)
But the researchers note the results cannot confirm cause and effect, because inactivity could be a symptom of poor mental health, or the cause of it, while being active could be a sign someone is in a good place mentally, or the other way around. In other words, it can’t be certain that one lifestyle choice causes either good or poor mental health.
“Depression is the leading cause of disability worldwide, and there is an urgent need to find ways to improve mental health through population health campaigns,” said Adam Chekroud, an assistant professor of psychiatry at Yale University, and coauthor of the study.
“Exercise is associated with a lower mental health burden across people no matter their age, race, gender, household income and education level. Excitingly, the specifics of the regime, like the type, duration, and frequency, played an important role in this association.”
More isn’t always better
The biggest reduction in poor mental health was seen for those exercising for 30 to 60 minues. Exercising for longer also showed benefits, but exercising for more than three hours a day was associated with worse mental health than not exercising at all.
This is because people who excessively exercise may show obsessive characteristics, the researchers said, which could put them at risk of mental health problems like eating disorders, or becoming “addicted” to exercise.
“Previously, people have believed that the more exercise you do, the better your mental health, but our study suggests that this is not the case,” said Chekroud. “Doing exercise more than 23 times a month, or exercising for longer than 90 minute sessions is associated with worse mental health.”
Team sports could be good for improving mental health because they reduce social withdrawal and isolation, he continued. The team hope the study could help medical professionals personalise exercise recommendations, and match people with exercises that could help improve their mental health, rather than giving them a blanket recommendation to simply increase their activities.
“One of the nice things is the accessibility of this,” Chekroud told TIME . “It seems like some of the benefits are pretty in reach for most people.”