The Effects of Aerobic Training on Subclinical Negative Affect: A Randomized Controlled Trial

Objective: The antidepressant and anxiolytic effects of aerobic exercise are well known, but less is known about its effects on subclinical levels of trait negative affect in healthy but sedentary adults. In the present study, we test the effects of a 3-month randomized controlled trial of aerobic exercise training in young to midlife adults on trait measures of depression, anxiety, hostility, and anger. Method: One-hundred and 19 men (n = 56) and women (n = 63) aged 20-45 were randomized to 1 of 2 conditions: (a) 12 weeks of aerobic exercise after which they were asked to halt exercising and decondition for 4 weeks, or (b) a 16-week waitlist control group. Assessments of depression, anxiety, hostility and anger were completed at study entry, Week 12 and Week 16. Results: At study entry, participants scored low on measures of depression, anxiety, hostility and anger. Analyses among the intent-to-treat and per protocol samples found significant treatment effects of aerobic training for hostility and depression, but not for anxiety and anger. Within-group analyses demonstrated that depression and hostility scores decreased in the exercise group over the course of the intervention, while remaining stable in the control group. These effects persisted for the exercise group at nonsignificant levels after 4 weeks of deconditioning. Conclusions: Aerobic exercise training has significant psychological effects even in sedentary yet euthymic adults, adding experimental data on the known benefits of exercise in this population.