MDD is the leading cause of disability for individuals ages 18 to 44 in the United States and the third greatest cause of disease burden worldwide [35]. Even with adequate pharmacological and psychosocial interventions, the rate of relapse, quality of life, and functioning often remain impaired for individuals with MDD [3, 18, 36]. Thus, new, adjunctive treatments, such as exercise, to improve depression and its comorbid conditions are needed [20, 37].
