Exercise Dose Required to Improve Quality of Life and Fatigue in Breast Cancer Survivors

Abstract

Survivors of breast cancer often cope with negative side effects resultant to their diagnosis and subsequent medical treatment. These effects, which include decreased aerobic capacity, psychosocial impairment, poor body image, and fatigue, may negatively impact quality of life (QOL). Previous studies have shown exercise to be effective in reducing or alleviating many of these side effects leading to an improvement in QOL. However, most studies have not been designed to evaluate the exercise dose needed to generate a significant change in fatigue and QOL. PURPOSE: The purpose of this study was to examine the exercise dose required to significantly improve QOL and decrease fatigue in breast cancer survivors. METHODS: Twenty-one breast cancer survivors (43–79 years, > one month post-treatment) were randomly assigned to either an exercise group (n=1 1) or control group (n=10). The exercise group participated in a low to moderate intensity (30–50% heart rate reserve) aerobic exercise program three times a week for ten weeks. The control group did not participate in the exercise program or change their normal daily activities. Weekly quality of life and fatigue were assessed with the Quality of Life Index for Patients with Cancer and the Schwartz Cancer Fatigue Scale, respectively. All measures were collected on the same day of the week and at a similar time of day. RESULTS: Statistical analysis revealed a significant improvement in QOL in the exercise group compared to the control group (p = .0003) by week 4 and this difference was maintained for weeks 5–10. The exercise group increased QOL 18.2% from pre to post-training (Mean (SD) 79.1 (16.1) to 93.5 (6.6) while the control group decreased QOL 3.5%, 85.1 (19.9) to 82.2(13.4). The exercise group showed a significant reduction in fatigue by week two compared to the control group (p = .0001) and this difference was maintained for weeks 3-10. The exercise group reduced fatigue 56.1% 18.0 (6.1) to 7.9 (2.4) while the control group increased fatigue 31.9%, 12.2 (4.9) to 16.1 (8.0). CONCLUSIONS: These results indicate that low to moderate intensity exercise is of sufficient strength to improve QOL and fatigue in breast cancer survivors in just a few weeks. This relatively low dose-response relationship may help improve exercise adherence, general health, and well-being in this population.