In the past, cancer patients were usually advised to rest and avoid physical effort. However, it is now well established that excessive rest and lack of physical activity may result in severe deconditioning and thus reduced physical functioning. Furthermore, women undergoing chemotherapy or radiation therapy as adjuvant treatment for breast cancer commonly experience debilitating side effects. One of the main side effects of radiation therapy is fatigue; common side effects of chemotherapy are nausea and vomiting, fatigue, weight gain and mood disturbances. These side effects interfere with daily activities such as self-care or return to work. Physical exercise has been reported to improve the underlying conditions in people with a range of chronic diseases.
This review evaluated physical exercise as a means of counteracting several of the side effects that cancer treatments (chemotherapy and radiation therapy) induce. It included nine controlled clinical trials with a total of 452 participants. Results suggest that physical exercise can improve physical function even during cancer treatment. Also, fatigue may be lessened through exercise although there is insufficient evidence to conclude this. There is still not enough evidence about the effect of exercise on outcomes such as mood disturbances, immune function and weight gain. Moreover, there is a lack of evidence for harms of exercise during adjuvant cancer treatment.