Blumenthal and colleagues (Blumenthal et al., 1999) conducted a 16-week randomized clinical
trial comparing exercise, sertraline, and a combination of exercise and sertraline. They found
that all 3 conditions were successful in reducing depression scores and there were no significant
differences among the conditions. Patients in the exercise condition and the combined exercise
and medication condition demonstrated significantly improved aerobic capacity from baseline
while the medication group demonstrated no such change. Further support for the role of
aerobic exercise in reducing depressive symptoms comes from Penninx and colleagues
(Penninx et al., 2002). Using data from a single blind randomized controlled trial, they
examined the effects of aerobic exercise, resistance exercise, and health education on
depressive symptoms and physical functioning in a sample of older adults with osteoarthritis
of the knee. Participants in the aerobic exercise condition demonstrated significant
improvements in depressive symptoms compared with participants from the other 2 conditions,
and also reported less disability and higher walking speed at follow-up than the control group