Making room for one additional 30-minute workout or adding in 5,000 steps in a day every week may reduce women’s incidence of depression by 19%. Even modest adjustments to exercise weekly may prevent nearly one in five cases of the disorder, a new study found.
Routine physical activity has been touted as a way to improve mental health and reduce the risk of depression and the symptoms associated with it, but research seldom quantifies how much may make the difference. Women are about twice as likely to be diagnosed with depression compared to men, and this study, conducted in South Africa by Discovery Vitality, a health insurer that incentivizes its members by rewarding financial decisions with wellness and fitness benefits, homed in on what kind of exercise uptick may benefit women’s risk for depression.
“By demonstrating an intervention that anyone can access, we start to bring depression out of the clinical hallways [and] into the street, which is actually where depression lives,” Dr. Mosima Mabunda, coauthor of the paper and Discovery Vitality’s head of wellness, tells Fortune. “We can structure environments that allow us to hopefully reduce the prevalence of depression.”
From low to moderate exercise
The study, published last month in the International Journal of Physical Medicine & Rehabilitation, examined almost 50,000 Discovery Vitality members from 2013 to 2015 who were not diagnosed with depression at the start of the study. Researchers tracked the participants’ exercise using fitness trackers and recorded attendance at gym visits or fitness-related events, who were then awarded points for various exercises depending on duration and intensity. The study then compared exercise habits alongside diagnosed cases of depression in the group. The researchers found that even small adjustments to weekly exercise made a difference in women's depression incidence, specifically going from low to moderate intensity for 30 minutes—this looks like moving at an average of at least 5.5 km/hr, swimming at an average of at least 1.5 km/hr, or cycling at an average of at least 10 km/hr, per the study. It also mirrors a typical gym workout. While the research doesn’t distinguish the baseline in which to add this additional activity, the participants all began the study at low levels of fitness. The current guidelines in the U.S. recommend 150 minutes of weekly moderate-intensity activity or 75 minutes of weekly vigorous-intensity activity and at least two days of strength training.
The study didn’t find a significant association between exercise and depression reduction in men, in part because women were more likely to be diagnosed with depression, and therefore, the sample size wasn't large enough to detect a pattern in men. Previous studies, however, point to the mental health benefits of routine physical activity, regardless of sex.
While exercise alone doesn’t heal all depression, Mabunda hopes studies like this one normalize the discussion around active measures that protect mental health. The researchers write that being able to test for other factors that may affect one's ability to exercise, like family history, socioeconomic status, and geographic location, could give more robust results in the future.
“When people know their risk, they're more likely to take action,” she says.
Exercise on the brain
While the direct mechanisms for how exercise affects our mental health are still being studied, exercising increases blood flow to the brain, which provides it with oxygen and nutrients. It can also promote the release of those feel good hormones associated with reward and pleasure and is recommended as a preventive measure to developing dementia and Alzheimer’s. Mabunda also speculates that routine exercise can increase self-esteem and confidence, something she resonates with personally.
“I'm able to be a lot more focused. I'm able to be a lot more confident in how I show up at work,” she says.
The study steers away from the idea that you need to be out of breath, or train for hours on end for something as intense as an Iron Man, to get mental health results. Finding something you actually like doing helps you stick with it more, and therefore, benefit more consistently. Walking with those you care about, hiking, or doing a routine gym workout all fit into the mold.
“It’s almost always possible to find something you enjoy,” Mabunda says.
