In the Upper Bavarian Field Study a representative community sample of 1,536 persons (from 15 years of age and upwards) was interviewed by research psychiatrists. Twenty-seven percent of the respondents reported taking regular and 26.2% occasional physical exercise. Physical inactivity as well as depression were significantly associated with the female gender, increasing age, low socioeconomic status and the presence of a somatic disorder. Using a logistic regression model, the relation between physical activity and depression was measured by the odds ratio with subjects reporting regular physical activity as the reference group. Cross-sectional analysis revealed that after controlling for potential confounder variables the odds ratio for depression was, at 3.15, significantly higher for the physically inactive compared to the regular exercisers. The odds ratio for the group practising occasionally (1.55) was also elevated but not statistically significant, 87.3% of the subjects who participated in the baseline study were reinterviewed five years later. In contrast to the cross-sectional findings, low physical activity at wave 1 was not a risk factor for developing depression at wave 2.
Siegfried Weyerer (Sat,) studied this question.