Research Associated With Exercise and Cancer
The first real research linking exercise to improved quality of life and management of fatigue was done by Winningham, MacVicar, and Burke (1986) with a population of patients with breast cancer, during a time in medical thinking when the typical recommendation for patients with cancer was increased rest. During the1980s, more than 40 studies demonstrated that physical activity in patients with cancer improves their functioning and quality of life (QOL) (Young-McCaughan et al., 2003). Winningham and colleagues published guidelines for exercise use in the cancer population. Since that time, many others have suggested guidelines for exercise use in cancer populations.
Today, the relationship between exercise and improved physical and mental well- being is well established for healthy people as well as people with cancer (Hacker, 2009). However, most research on exercise and cancer has involved patients with breast cancer, possibly because of the high number of breast cancer survivors in the population as compared to other cancers. For example, a large retrospective analysis of multiple studies involving patients and/or survivors of breast cancer (Wanchai, Armer, & Stewart, 2011) demonstrated overwhelmingly that supervised and home-based exercise programs could provide benefits for participants, ranging from improved QOL scores, to enhanced self-esteem, improved mood, greater aerobic fitness, higher level of functioning, and decreased pain and fatigue. Unfortunately, because many early studies were conducted with women with breast cancer only, their generalizability is limited (Visovsky & Dvorak, 2005).
Other studies conducted involved patients of varying types of cancer, but due to the number of variables and differences among then, drawing conclusions from such cohorts is difficult. Two large prospective observational studies suggest, however, that regular exercise following treatment for colon cancer may reduce the risk of recurrence and death. These data are significant in that they suggest that lifestyle factors, not just the molecular aspects of the tumor play a role in treatment outcomes (National Cancer Institute, 2006).
Demonstrating exercise’s physical effect on functional status, weakness, and cancer-related fatigue (CRF) has been primary endpoints in many studies (Hanna, Avila, Meteer, Nicholas, & Kaminsky, 2008). Although few studies have focused solely on CRF, exercise has been demonstrated as successfully reducing CRF in multiple studies, leading some to postulate that exercise currently offers the best nonpharmacologic option for reducing CRF (Hanna et al., 2008). Unfortunately, much is still unknown, including the best timing, duration, or intensity of exercise.
Other studies have measured the effect of exercise on depression, anxiety, and stress. In one study, a significant reduction in anxiety was observed following just one exercise session (Blanchard et al., 2001). Still others have found the aerobic physical exercise during or after cancer treatment resulted in improved QOL, body composition, fatigue, and endurance; additional benefits included decreased pain, diarrhea, nausea, and sleep disturbances, and improved life satisfaction, symptoms of depression, and self-esteem (Visovsky & Dvorak, 2005).