Plenty of research has shown that exercise can help reduce depression and anxiety, and it is frequently recommended for people with those and other psychological disorders.
But if physical activity can help reduce negative emotions, can it also increase positive ones in people who are psychologically healthy? In other words, can it enhance our happiness?
It’s also quite probable, the review found, that we can reap some measure of that happiness benefit with short or infrequent bursts of physical activity.
“Even a small change of physical activity makes a difference in happiness,” said Weiyun Chen, one of the review’s authors and an associated professor of kinesiology at the University of Michigan, in a released statement.
Different types of studies
For the review, Chen and her co-author, doctoral student Zhanjia Zhang, analyzed the findings from 23 studies on happiness and physical activity published since 1980. Some of the studies were small (less than 100 participants), but others were quite large, and collectively the studies involved more than 500,000 people.
Fifteen of the studies were observational. Those studies compared how much exercise people said they engaged in each week with how happy they were, based on their answers to assessment questionnaires. Most involved healthy populations, ranging in age from teenagers to the elderly, but three targeted special populations: children and teens with cerebral palsy, drug abusers and women who had survived ovarian cancer.
The other eight studies in the review were interventional. They enrolled people into some form of an exercise program (the “intervention”) and then compared their happiness levels before and after. Six of these studies were randomized controlled trials — ones that randomly assigned one group of people to an exercise program and another group to a control group that did not engage in the intervention. The happiness levels of both groups were compared at the end of the study to see if there were any differences.
Participants in the interventional studies came from various demographic groups, including college students, older adults, postmenopausal women and cancer survivors.
What the studies revealed
The findings from all this research “generally support the beneficial relationship between [physical activity] and happiness,” Chen and Zhang write.
All of the observational studies found a positive association between exercise and happiness. A Canadian study that involved more than 17,000 people reported, for example, that people who were inactive and remained inactive were three times more likely to be unhappy two years later than inactive people who had changed their habits and were engaged in some kind of regular physical activity at that two-year milestone.
Observational studies, however, can show only a correlation between two things — in this case, exercise and happiness — not a direct cause-and-effect. Although these studies adjusted their findings for a variety of confounders that might also explain why people who are physically active are happier (they may be in better health, for example), the results still might have been influenced by factors that the studies did not address.
And, indeed, the findings from the interventional studies — which offer stronger evidence than observational ones — were not consistent. Only four of the eight studies found a significant difference in change of happiness between their intervention and control groups.
Interestingly, in the studies that did find physical activity helped people feel more upbeat, it didn’t matter what type of exercise was involved. Aerobic exercise (such as walking and jogging) and stretching/balancing exercise (such as yoga and tai chi) were both linked to happier moods.
Most surprising, perhaps, was the finding that people didn’t have to invest a lot of time into exercising to feel happier. In some of the studies, working out just once or twice a week — sometimes for as little as 10 minutes — produced positive results.
No downside, many benefits
As Chen and Zhang point out in their paper, because of the limited number of randomized controlled trials on this topic in the medical literature, it’s impossible to draw any firm conclusions about whether physical activity enhances happiness.
It’s also quite possible, they say, that the social aspect of physical activity — being out and about with other people — may be what’s influencing moods in these studies, rather than any effects that exercise may have on the brain.
Still, for most people, becoming more physically active has no downside, only a long list of benefits, including lowering your risk of heart disease and certain cancers, helping you manage blood sugar and insulin levels, improving your sleep, strengthening your bones and muscles, reducing your risk of falls, and improving your sexual health.
Those are enough to make anyone feel happier.
FMI: You’ll find an abstract of the study on the Journal of Happiness Studies website, but the full study is, unfortunately, behind a paywall.