Effects of exercise on stress : a meta-analysis

Physical exercise is frequently prescribed by clinicians and researchers as an effective stress reduction technique. There has been some research to support this assertion, however the research has been varied in its methodological rigor. The design problems, variations in exercise programs, and the use of a wide range of psychological measures have made results difficult to interpret. Additionally, the psychological benefits and underlying change processes have not been clearly delineated. The purpose of this study was to conduct a meta-analysis of the research in this area in an attempt to answer specific questions regarding the role of exercise in stress reduction. This meta-analytic approach was chosen because it permits the quantitative integration of findings of several studies and consideration of the variables that may influence the variance in study outcomes. The effectiveness of exercise as a treatment for stress, the type of exercise that was most beneficial, and the type of individual who gained the most from the exercise intervention was examined. The 61 effect sizes, which were calculated from 24 studies included in the meta-analysis, were coded along with other variables considered important. Study components such as design type, stress level, type of exercise program, program length, frequency of exercise sessions, attrition rate, psychological measure, composition of sample, gender, and study type were coded as independent variables. Effect size was the dependent variable. Analysis of variance revealed that exercise was an effective stress reducer, stressed people gained a greater stress reduction effect than minimally stressed people, and there were no differences between trait and state anxiety reduction from pre- to post-exercise program. In addition, a one-way ANOVA indicated that there was a significant difference between program lengths. Examination of the means revealed that an 8- to 12-week program was most effective in reducing stress. Although there was a greater effect size for unpublished studies than published studies, the pattern of change for each study type was similar. The significance of these results and recommendations for future studies are discussed.Education, Faculty ofCurriculum and Pedagogy (EDCP), Department ofGraduat