Mediators of exercise effects on quality of life in cancer survivors

There is growing evidence that exercise is beneficial for cancer patients' quality of life. In a study just published on line in the journal Medicine & Science in Sports & Exercise, we explored via which pathways this effect may come about. More specifically we explored if combined resistance and endurance exercise improves cardiorespiratory fitness and muscle strength, thereby reducing fatigue and improving global quality of life (QoL) and physical function among cancer survivors who completed curative treatment including chemotherapy.
One hundred and eighty six cancer survivors were assigned to a 12-week exercise intervention and 91 patients to a wait list control group (WLC).
Compared with WLC, exercise increased cardiorespiratory fitness and reduced general and physical fatigue. The exercise effect on physical fatigue was mediated by change in cardiorespiratory fitness, while higher hand-grip strength was significantly associated with lower physical fatigue, and better lower body muscle function with lower physical and general fatigue. Lower general and physical fatigue were significantly associated with higher global QoL, and physical function.
We concluded that beneficial effects of exercise on global QoL and physical function in cancer survivors were
mediated by increased cardiorespiratory fitness, and subsequent reductions in fatigue.