New study offers 'strongest evidence' yet that exercise helps prevent depression
Does physical activity reduce depression, or does depression reduce physical activity?
It's a quintessential chicken and egg scenario — and a question that's plagued scientists for some time.
Now, thanks to the power of modern genomics, a new study published in JAMA Psychiatry provides the "strongest evidence" yet that exercise has a protective effect against depression.
Using the genetic data of 300,000 adults, researchers at Massachusetts General Hospital found people with higher levels of physical activity had lower odds of major depressive disorder, according to lead researcher Karmel Choi.
"We found evidence that higher levels of physical activity may causally reduce risk for depression," Dr Choi said.
In fact, the research shows that replacing sedentary behaviour with 15 minutes of vigorous activity each day can reduce depression risk by roughly 26 per cent.
"On average, doing more physical activity appears to protect against developing depression … and any activity appears to be better than none."
While the study showed physical activity could prevent depression, it found no evidence that being diagnosed with depression affected a person's ability to exercise.
But people diagnosed with depression are still at an increased risk of reduced physical activity, according to Joseph Firth, a senior research fellow at Western Sydney University who was not involved in the study.
"It's still the case that people with depression are less active than the general population, but [the study] is saying it's not necessarily the depression itself that's driving that relationship," Dr Firth said.
"It could be social factors, rather than the actual genetics of depression.
"So, it's still worth thinking about physical activity interventions for people with depression."