What is the Relationship between Depression and Physical Activity?

In a previous post (10/2/14), I reported a study suggesting that physical activity improves depression. In a new study published in the October 15 issue of JAMA Psychiatry, Drs. Snehal M. Pinto Pereira, Marie-Claude Geoffroy, and Christine Powersuggest a bidirectional relationship between depression and physical activity, i.e., physical activity may decrease depressive symptoms and, in turn, depressive symptoms in early adulthood may be an impediment to physical activity.