Abstract
This cross-sectional study assessed the association between depression and PA in university students of both genders and the role of body image perception as a potential effect modifier. Undergraduate students (N = 3706) from seven universities in the UK completed a self-administered questionnaire that assessed sociodemographic information; a range of health, health behaviour and health awareness related factors; the modified version of Beck's Depression Inventory (M-BDI); educational achievement, and different levels of physical activity (PA), such as moderate PA (at least 5 days per week moderate exercise of at least 30 minutes), and vigorous PA (at least 3 days per week vigorous exercise of at least 20 minutes). Only 12.4% of the sample achieved the international recommended level for moderate PA, and 33.1% achieved the recommendations for vigorous PA. Both moderate and vigorous PA were inversely related to the M-BDI score. Physically active students, regardless of the type of PA, were significantly more likely to perceive their health as good, to have higher health awareness, to perform strengthening exercises, and to be males. The stratified analyses indicated that the association between depression and PA differed by body image. In students perceiving their body image as 'just right', moderate (>4th percentile) and high (>5th percentile) M-BDI scores were inversely related to vigorous PA. However, in students who perceived their body image as 'overweight', the inverse association was only significant in those with high M-BDI scores. We conclude that the positive effect of PA on depression could be down modulated by the negative impact of a 'distorted' body image on depression. The practical implications of these findings are that PA programmes targeting persons with depressive symptoms should include effective components to enhance body image perception.