A new study looks into why and how physical activity can boost your mood so much. Here’s what you should know.

It’s well known that exercise helps boost your mood—some studies have actually suggested that long-term exercise is just as good at treating depression as medication and other accepted behavioral therapies. Other research shows that one bout of exercise can elevate mood for minutes to hours.

And while it’s clear that folks with depression benefit from exercise, it's never been completely clear why or how. But a small new study in the journal Medicine & Science in Sports & Exercise says the endocannabinoid (eCB) system may have something to do with this benefit.

About Those Endocannabinoids

Endocanna-what? That big "e" word refers to our body's cannabinoid molecules and receptors, found on our cells, said lead author Jacob Meyer, Ph.D., assistant professor of kinesiology at Iowa State University. If some of these words sound familiar, it's likely from discussions about cannabis (yep, the marijuana plant), because cannabis also contains cannabinoids. If you're still confused, yes, your body contains eCB naturally, too—regardless of whether you have used weed or other cannabis products.

When cannabis receptors in the body are activated, they enhance brain connections that may play a role in pain and depression. And exercise gets concentrations of eCB moving throughout the body.

Dr. Meyer’s team says if we can understand how endocannabinoid levels work with mood and exercise, it could lead to new and better ways to treat depression—ways that wouldn't have to involve medication, but might include "optimal exercise interventions," he said.

A Beneficial 'Cycle'

In the study, a group of 17 women between ages 20 and 60 with major depressive disorder, normally just called "depression," did two half-hour sessions on stationary bikes, with one session at "prescribed" moderate intensity, meaning it wasn't easy, but it wasn't heavy-duty either. For the second round, participants had free choice about how intensely they wanted to pedal. Researchers said both sessions seemed to boost mood, but endocannabinoid levels increased only with moderate intensity exercise and not with "preferred intensity."

Participants filled out questionnaires both pre- and post-exercise. Before they started, and right after they finished a session, researchers took blood samples. Then at 10 minutes and 30 minutes, the scientists evaluated cyclists' mood and anxiety. They noted changes in endocannabinoids tied to mood improvements as long as 30 minutes after moderate exercise, which reaffirmed how the endocannabinoid system enhances mood after prescribed exercise—a positive finding for the researchers.

A Great Start

Prescribed moderate intensity exercise quickly boosts mood and then sustains that improved mood, Dr. Meyer said. Deciphering the role of "preferred exercise" was a bit fuzzier, since endocannabinoid levels stayed the same. He said that multiple factors probably make people feel better after exercise, and he wants more information.

Next steps for researchers include investigating even more ways that exercise can help people with mental disorders, Dr. Meyer said.

Meanwhile, with so much information out there about the benefits of exercise, there's never been a better time to start and stay with a physical activity program that you like, because exercise definitely likes you. Some ways to get the recommended 150 minutes of moderate-intensity exercise per week include the following, per the Centers for Disease Control and Prevention:

• Walking. Yep, plain old walking at a brisk pace of 3 to 4.5 mph counts as moderate exercise. Get those minutes in on the way to work, while walking your dog, or just for pleasure. Pop on some earbuds and listen your favorite music or podcast on the way.
• Cycling. Take pointers from this new study and give cycling a go, whether on a stationary bike or out in the world on level terrain. Biking 5-9 mph is considered moderate-intensity activity.
• Yoga. Namaste your way to a better mood. Look for classes at your local gym or yoga studio. Or, do a quick search for a full-body yoga routine on YouTube.
• Dancing. No matter what type of music you’re into, dance it out—ballroom dancing, line dancing, modern dancing, ballet, or even a Zumba class will get you moving and help enhance your mood.
• Swimming. Hit up your community pool and have some fun while improving your mood. Recreational swimming—yep, you don’t even have to swim a bunch of laps—jumping off the diving board, and slowly treading water are all ways to get moderate-intensity exercise. Just keep swimming!
• Gardening and housework. Even regular chores can count as moderate exercise. Raking, bagging grass or leaves, or pulling weeds will not only make your garden happy, but your mind, too. And things like cleaning your home’s floors, washing windows, putting groceries away, and other household tasks can work, too!