The initial review of the effects of physical activity in reducing cancer-related fatigue, published in The Cochrane Library in 2008, identified some benefits of physical activity on fatigue during and after adjuvant treatment but also identified a number of study design limitations. To evaluate the current state of knowledge on the effect of exercise on cancer-related fatigue both during and after cancer treatment, researchers conducted a review of studies published on or before March 2011. Where data were available, the researchers performed meta-analyses for fatigue using a random-effects model. Fifty six studies (28 from the original search and 28 from the updated search) involving 4068 patients were reviewed. A meta-analysis of all fatigue data, incorporating 38 comparisons, provided data for 1461 patients who received an exercise intervention and 1187 control patients. At the end of the intervention period, exercise was significantly more effective than the control interventions. Benefits of exercise on fatigue were observed for interventions delivered during or post-adjuvant cancer therapy, and were identified for patients with breast and prostate cancer but not for those with hematological malignancies. Aerobic exercise significantly reduced fatigue but resistance training and alternative forms of exercise were not found to be statistically significant. These data were published online in The Cochrane Library on November 14, 2012.
The results of the Cochrane review are not all that surprising. Exercise, particularly aerobic exercise, is recognized as being energizing. Non-aerobic exercise, such as yoga and resistance weight training, did not significantly reduce fatigue; however, they may be beneficial in reducing other symptoms, such as anxiety. The research team concluded that further work is needed to determine the most effective exercise for fatigue management, including type, frequency, and duration. Tehere also is a need to develop and utilize consistent outcome measures.