Jacqueline Drouin and Lucinda Pfalzer, Ph.D.
Exercise is now being recognized as an important component of the fight against cancer. There is evidence that exercise can be of benefit in three ways to manage cancer and its symptoms. First, epidemiological evidence indicates that exercise, combined with healthy lifestyle practices, appears to prevent certain types of cancers. The cancers that are reported to occur less frequently in active people are cancers of the colon, breast, prostate, and possibly the lung, digestive system, thyroid, bladder and the hematopoietic system (Lichtenstein, et al. 2000; Sternfeld, et al., 1992; Frisch, et al., 1985). Second, aerobic exercise has been shown to provide benefits specifically to people undergoing treatment for cancer. These benefits include improved physical function and relief from fatigue, nausea, and depression (Pinto & Maruyama, 1999). Third, exercise enables people who survive cancer with a means to recover their physical functions and return to a healthy and active lifestyle (Augustine & Gerber, 2000, Friendenreich & Courneya, 1996).
Despite evidence that supports exercise as a means to manage cancer and its symptoms, people with cancer are routinely told to rest and limit their physical activity (Ream & Richardson, 1999). However, rest and diminished physical activity lead to further declines in function that worsen the symptoms of cancer, such as fatigue, nausea and depression (Ream & Richardson, 1999, Dimeo, et al., 1998, Segar, et al., 1998, MacVicar, et al., 1989, Winningham, et al., 1986). This worsening of symptoms leads to chronic disabilities that continue to plague cancer survivors in the recovery and remission phases of their disease. Chronic disabilities that continually affect cancer survivors include limited physical function, chronic fatigue, and depression (Dimeo, et al., 1998, Segar, et al., 1998).
The following discussion on cancer and exercise will present three topic areas. The first topic area will include an overview of cancer epidemiology and pathology, cancer causes, and methods of cancer diagnosis. The second topic area will present a review of the literature on experimental studies related to exercise and cancer. The final portion of this paper will describe guidelines for the development of safe and effective exercise protocols for people undergoing treatment for cancer, recovering from cancer, in remission from cancer, or living with cancer.