How much exercise can improve your mood?

You’ve heard that exercise can make you happier and less stressed. But just how much physical activity do you need to turn around a bad day? Researchers have been hard at work trying to answer that question, and while there’s no one get-happy prescription for everyone, evidence indicates that pretty much any amount of exercise—even a 15-minute walk—can help to turn a frown upside down.

“Exercise is messy,” according to Wendy Suzuki, PhD, professor of neural science and psychology at New York University and the lead author of a recent large-scale study review on exercise and the brain. There are so many things that happen to the body during a single workout—increased heart rate and metabolism, changes in neurochemical pathways—that it can be difficult to determine which actions lead to each change in the brain.

But when it comes to mood, changes in the brain are relatively swift and easy to see. “A single bout of exercise can change neurotransmitter levels in the brain, increasing dopamine, serotonin, and endorphins—all of which have been associated with a good mood and/or pain management,” says Suzuki. “These neurochemicals are the brain’s natural opiate.” Add exercise, and your brain turns on the feel-good chemicals almost instantly.