Can an hour of exercise a week prevent depression?

Up to 12 percent of depression cases can be prevented by exercise according to the results of a major study published this week.

Over the course of 11 years, 33,908 Norwegian adults had their levels of exercise and symptoms of depression and anxiety monitored.

The study found 12 percent of cases of depression could have been prevented if participants did at least an hour of physical activity each week.

Regular leisure-time exercise of any intensity provides protection against future depression but not anxiety, according to the paper.

“These findings are exciting because they show that even relatively small amounts of exercise – from one hour per week – can deliver significant protection against depression," said one of the study's lead authors Associate Professor Samuel Harvey from the Black Dog Institute and UNSW in a statement.

The results of the study show even small amounts of exercise can protect against depression, with mental health benefits in both men and women of all ages.

The findings have been published in the American Journal of Psychiatry and confirm what was has long been recommended by health companies like Bupa. 

Bupa's Dr Tim Ross, says the mental health benefits of exercise are wide ranging- for the mind and body.

"Exercise is a great way to help with depression. Withdrawal is a significant factor with depression and going for a walk, or something more strenuous, gets people out and about and re-connecting with their world."

"As a practising GP, exercise is frontline in my management for patients with depression. Movement gives an uplift in metabolism and increases energy flow, something that is lacking in many people with depression."

The authors of the study say it reinforces the role exercise should play in improving mental health.

“We’ve known for some time that exercise has a role to play in treating symptoms of depression, but this is the first time we have been able to quantify the preventative potential of physical activity in terms of reducing future levels of depression,” says Assoc Prof Harvey.

“We are still trying to determine exactly why exercise can have this protective effect, but we believe it is from the combined impact of the various physical and social benefits of physical activity."

“These results highlight the great potential to integrate exercise into individual mental health plans and broader public health campaigns." 

"If we can find ways to increase the population’s level of physical activity even by a small amount, then this is likely to bring substantial physical and mental health benefits.”