The purpose of the present study was to address
1) whether exercise provides protection against new-onset depression and anxiety and
2) if so, the intensity and amount of exercise required to gain protection and, lastly,
3) the mechanisms that underlie any association.
A “healthy” cohort of 33,908 adults, selected on the basis of having no symptoms of common mental disorder or limiting physical health conditions, was prospectively followed for 11 years. Validated measures of exercise, depression, anxiety, and a range of potential confounding and mediating factors were collected.