THE EFFECT OF EXERCISE ON CLINICAL DEPRESSION:
A META-ANALYSIS
LYNETTE L. CRAFT AND DANIEL M. LANDERS
ARIZONA STATE UNIVERSITY
The effect of exercise on negative affect has been examined in hundreds
of studies. However, the effect of exercise on diagnosed clinical
depression has received far less attention in the literature. While
many studies have investigated various types of exercise on depression,
poor methodological techniques have predominated and results have been
conflicting. The purpose of the study was to investigate the effect
of exercise on clinical depression and depression resulting from mental
illness by using the technique of meta-analysis. Studies were chosen
if they examined the effect of a chronic exercise paradigm (independent
variable) on depression (dependent variable). Each study was coded
for variables related to study information, design, subject, exercise,
and dependent measure characteristics which could potentially moderate
the effect of exercise on depression. Moderator variables were analyzed
using analysis of variance (ANOVA). Results from 30 studies showed
an overall mean effect of -.72. This study concluded that aerobic
and nonaerobic exercise programs were effective in alleviating depression
(ESs= -.94, -.82). Those individuals who were initially more depressed
showed the greatest response to an exercise intervention (ES= -.88).
Exercise was also found to be as effective as other treatments when compared
to psychotherapy and behavioral interventions (ESs= -.06, .03). Moderating
variables and implications for the prescription of exercise as a treatment
for depression are discussed.
An abstract of this presentation is published in Medicine and Science
in Sports and Exercise, 30 (5), May 1998 Supplement, S117.