As little as one hour per week of exercise can offer “significant protection” against depression, an Australian research team has found.

The study revealed that regular exercise of any intensity can prevent depression, with mental health benefits seen regardless of age or gender.

Analysis, published in the American Journal of Psychiatry, involved 33,908 Norwegian adults who had their levels of exercise and symptoms of depression and anxiety monitored over 11 years.

The research team found that 12 per cent of cases of depression could have been prevented if participants took part in just one hour of physical activity each week.

“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,” said lead author, associate professor Samuel Harvey, from the Black Dog Institute and University of New South Wales in Australia.

Healthy participants were asked to report the frequency of exercise they took part in and at what intensity: without becoming breathless or sweating, becoming breathless and sweating, or exhausting themselves. At a follow-up stage, they completed a self-report questionnaire to indicate any emerging anxiety or depression.

Researchers also accounted for variables which might impact the association between exercise and common mental illness. These included socioeconomic and demographic factors, substance use, body mass index, new onset physical illness and perceived social support.

Results showed that people who reported doing no exercise had a 44 per cent increased chance of developing depression compared to those who were exercising one to two hours a week.

“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 associate professor Harvey.

He added: “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.”