Self-selected intensity exercise in the treatment of major depression: A pragmatic RCT.

Objective: The purpose of the study was to determine the therapeutic effect of physical exercise for patients with unipolar depression. Participants took part in an 8-week walking/running aerobic exercise program at a local sports club.

Methods: Forty-six outpatients aged 18-65 years and diagnosed with mild to severe depression (ICD-10 criteria) were randomly assigned to an intervention group or wait list. Treatment as usual was continued. The Hamilton Rating Scale for Depression (HRSD-17) served as the main outcome measure. Secondary outcome measures were Beck Depression Inventory (BDI-II), Fitness Index (FI), and VO(2) max as estimated by Urho Kaleka Kekkonen or UKK 2-km Walk Test.

Results: Out of forty-six participants, 24% dropped out. Participants attended 58% of exercise sessions. All randomized participants were included in intention-to-treat (ITT) analysis. Analysis of covariance or ANCOVA showed a large reduction of depressive symptoms in HRSD-17 scores (Cohen's d: 1.8; mean change 8.2, p < .0001). BDI-II (Cohen's d: 0.50; mean change: 4.7, p = 0.09), FI scores (Cohen's d: 0.27; mean change: 5.3, p = 0.08), and VO2 max did not change significantly.

Conclusions: We observed a large and clinically significant change in HRSD-17 scores. Moderate changes in BDI-II scores without clinical significance and small changes in physical fitness assessments were observed.