An exercise regimen prescribed by a health professional may activate cannabinoid molecules in the brain, which could have a positive effect on depression. File Photo by Maridav/Shutterstock

Aug. 14 (UPI) -- Working out is known to improve the moods of people with depression, and now researchers may have figured out why.

An exercise regimen prescribed by a health professional may activate cannabinoid molecules in the brain, which could have a positive effect on depression, according to a study published Wednesday in the journal Medicine and Science in Sports and Exercise.


"Finding alternatives to medication is important for the treatment of depression," Jacob Meyer, a researcher at Iowa State University and study author, said in a news release. "If we can figure out how exercise works with the endocannabinoid system, we could then design optimal exercise interventions."

The researchers prescribed two separate 30-minute stationary bike exercise sessions to 17 women with depression. Women had a moderate workout in one session, while women in the other session chose the intensity level for their own workout.

The researchers took blood samples from the women after each session and gauged their mood and anxiety levels 10 minutes and 30 minutes after the workouts.

Meyer says some of the women in the preferred group chose to workout at a lighter intensity. Others worked out in intervals with varied intensity.

Women in each session had improved moods, but those in the moderate-intensity group had elevated levels of endocannabinoids.

"Having someone else prescribe the exercise could be involved in both the psychological and biological response to exercise," Meyer said.

These results mirror those gathered by Meyer following a similar 2016 study on exercise and depression.

"These results show us that the effect of prescribed moderate-intensity on mood is generally pretty quick and lasts for a while at a relatively sustained rate," Meyer said. "However, given that people felt better after the preferred exercise session, even though it didn't change endocannabinoid levels, multiple factors are likely involved in how exercise makes people feel better."