Several mechanisms have been proposed for the antidepressant effects of exercise, which can be divided in two categories: psychological and biological. Psychological variables include increased autonomy, physical wellbeing, enhanced quality of life, or increased self-esteem and mood [79, 80]. In this review, we opted to review the most promising biological causes of exercise given the burgeoning literature in this area. Specifically, key biological variables include several growth factors (e.g., brain derived neurotrophic factor; BDNF), oxidative stress, and genetics as they have been implicated in the role of exercise-induced neurogenesis and its antidepressant effects [27, 81–90].
