People who are physically active three times a week may reduce their risk of depression, a new study suggests.

UK researchers followed the progress of over 11,000 people born in 1958, until they reached the age of 50. Levels of physical activity and depressive symptoms were recorded at regular intervals during adulthood.

The study found that each additional session of physical activity undertaken each week reduced the odds of a person developing depression by 6%.

The researchers said that assuming the link is causal, this means that physical activity ‘has a protective effect against depression'.

"If an adult between their 20s and 40s who isn't physically active became active three times per week, they would reduce their risk of depression by approximately 16%," commented the study's lead author, Dr Snehal Pinto Pereira of University, College London (UCL).

She emphasised that this effect was seen ‘across the whole population and not just in those at high risk of clinical depression'.

"The more physically active people were, the fewer depressive symptoms they reported. Just as someone might be a little overweight but not clinically overweight or obese, many people who are not clinically depressed could still experience some depressive symptoms," she noted.

The study found a two-way relationship between exercise and depression - those who increased their weekly activities reported fewer depressive symptoms, but those with more symptoms tended to be less active.

"If everyone was physically active at least three times a week we would expect to see a drop in depression risk, not to mention the benefits for physical health, as pointed out by other research, including reduced obesity, heart disease and diabetes risk," added the study's senior author, Prof Chris Power of UCL.

Details of these findings are published in the journal, JAMA Psychiatry.

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