Relationship of exercise to fatigue and quality of life in women with breast cancer

The purpose of this study was to examine the direct and indirect relationships of level of exercise to cancer-related fatigue (CRF) and quality of life in women with breast cancer receiving chemotherapy. A pretest-posttest, one-group design was used. All 27 subjects received exercise instructions for an 8-week, progressive, home-based exercise program that accommodated to individual cycles of chemotherapy. Baseline measures taken before chemotherapy included CRF, quality of life, and a 12-minute walk. Weekly telephone interviews were used to collect data on CRF and exercise. The 12-minute walk was readministered at posttest. The subjects were young (M = 46.6 years) and 54.8% were sedentary. Posttest 12-minute walk distances increased over the baseline measure in nearly 60% of the subjects. Four multiple regression equations were computed to test the mediating effect of exercise on the relationship between CRF and quality of life using the standard approach to test mediation. The effect of exercise on quality of life was strongly mediated by CRF. CRF accounted for 71% of the variance in quality of life (p = 0.05). Different patterns of average and worst CRF were observed, with less CRF observed in the exercisers. Findings indicated that a low-intensity, home-based exercise program is feasible for women with breast cancer receiving chemotherapy. The program resulted in improved functional ability, reduced CRF, and improved quality of life for subjects who exercised. The pattern of CRF differed between subjects who exercised and those who did not. In addition to the importance of decreasing an unpleasant sensation, maintaining functional ability throughout the course of treatment may improve patients' resiliency and ability to continue with activities they see as important.