Fatigue mediates the effects of exercise on quality of life

Purpose: Fatigue is a common side effect of cancer treatment that impacts quality of life. Exercise is one approach suggested to improve fatigue. The purpose of this study was to explore the relationship of exercise to fatigue and quality of life. Methods: Thirty-one subjects with breast cancer were enrolled prior to beginning chemotherapy and 27 completed the study. All baseline measures were obtained before the first chemotherapy treatment. Subjects were instructed on a home-based, 8-week exercise program. Results: Women who adopted the exercise program (60%) showed significant increases in functional ability and less weight gain. Exploratory, stepwise multiple regression analyses suggested that the maximum effect of exercise on quality of life outcomes may be mediated by fatigue. Conclusions: The low-to-moderate intensity, home-based exercise program was feasible for some women with breast cancer receiving chemotherapy. The results suggest that exercise may affect quality of life and that this effect may be mediated by the effects of exercise on fatigue. Better retention of functional ability and better weight control are additional possible benefits of exposing breast cancer patients to increased exercise. A randomized, controlled clinical trial is needed to establish confidence in these observed relationships.