Effects of Exercise on Biobehavioral Outcomes of Fatigue During Cancer Treatment

Abstract

Cancer treatment is associated with decreased hemoglobin (Hb) concentration and aerobic fitness (VO_{2 max}), which may contribute to cancer-related fatigue (CRF) and decreased quality of life (QoL). Endurance exercise may attenuate CRF and improve QoL, but the mechanisms have not been thoroughly investigated. Objectives. To (a) determine the feasibility of conducting an exercise intervention among women receiving treatment for breast cancer; (b) examine the effects of exercise on Hb and VO_{2 max} and determine their association with changes in CRF and QoL; and (c) investigate changes in selected inflammatory markers. Methods. Fourteen women receiving chemotherapy for Stages I–II breast cancer were randomly assigned to exercise (n = 7) or usual care (n = 7). Women in the exercise group performed supervised, individualized treadmill exercise 2–3 times/week for the duration of chemotherapy (9–12 weeks). Data were collected 4 times over 15–16 weeks. Results. Recruitment rate was 45.7%. Sixteen women consented and 14 completed the trial, for a retention rate of 87.5%. Adherence to exercise protocol was 95–97%, and completion of data collection was 87.5–100%. Exercise was well tolerated. VO_{2 max} was maintained at prechemotherapy levels in exercisers but declined in the usual-care group (p < .05). Hb decreased (p < .001) in all participants as they progressed through chemotherapy. Exercise did not have significant effects on CRF or QoL. Changes in inflammatory markers favored the exercise group. Conclusions. Exercise during chemotherapy may protect against chemotherapy-induced decline in VO_{2 max} but not Hb concentration.