A 55-year-old woman with breast cancer who is undergoing chemotherapy presents with fatigue. She tried rest with little improvement, but she is concerned that exercise may increase her cancer-related fatigue.
Does exercise improve fatigue in patients undergoing treatment or post-treatment for cancer?
Aerobic and resistance-training exercise programs lead to decreased overall fatigue and an improved quality of life during and after treatment of cancer.
Because patients with cancer are surviving longer, they increasingly have to live with the long-term consequences of cancer therapy. Cancer-related fatigue affects 70 to 100 percent of patients with cancer.1 Fatigue affects the patient physically, emotionally, and mentally during and after treatment. It may have severe social and economic consequences, and can limit a patient's ability to carry out activities of daily living and participate in clinical trials.
Rest was initially recommended to combat cancer-related fatigue, but studies have shown that exercise is helpful in reducing fatigue associated with cancer.1 Impaired physical performance is a main cause of fatigue in patients with cancer, which leads to psychological distress. Improving physical performance through regular aerobic activity leads to improvement in performance status, reducing psychological distress and fatigue in these patients.2
The mode, intensity, duration, frequency, and location of exercise varied among the 28 studies included in this Cochrane review.1 Seven of the studies used walking as exercise, four studies used stationary cycling, and 13 studies used a range of patient-preferred modalities. Two studies investigated resistance training alone, whereas another study included flexibility training. Yoga was included in two studies, and seated exercise in one. The amount of exercise varied from two to seven days per week for 10 to 75 minutes per session, but the overall time spent exercising was rarely reported. Thirteen studies were home based, 16 were supervised and institution based, and others included both exercise locations.
The intervention period among the studies ranged from three to 32 weeks, with 12 weeks as the most common period. Stage of treatment varied among included studies, with 13 studies investigating during treatment, 11 after treatment, and four during and after treatment. The exercise group was compared with a control or usual care group in 16 studies, whereas two of the studies also encouraged participants in the control group to remain active. Although the included studies all compared an exercise program with usual care or less intense exercise, they differed in their standardized measures of fatigue. To combine the results of the studies, the authors used a statistical method—the standard mean difference—to create a common unit of measurement. The standard mean difference indicated that exercise helped to reduce fatigue. Although there was variation in the size of the effect, almost all of the studies showed less fatigue in the exercise group.
The National Comprehensive Cancer Network also recommends exercise as part of the management strategy of cancer-related fatigue during and after therapy.3 Although there is not a specific amount of activity recommended for patients with cancer, some studies have suggested that patients participating in three to five hours of moderate activity per week may experience fewer adverse effects, including fatigue.3 Further research is necessary to determine the most effective exercise regimen, but certain patients may benefit from referral to exercise specialists or physical therapists. Patients should have a program that is individualized to fit their needs based on sex, type of cancer, age, and physical fitness level at baseline.3
Background: Cancer-related fatigue is now recognized as an important symptom associated with cancer and its treatment. A number of studies have investigated the effects of physical activity in reducing cancer-related fatigue with no definitive conclusions about its effectiveness.
Objectives: To evaluate the effect of exercise on cancer-related fatigue during and after cancer treatment.
Search Strategy: The Cochrane Controlled Trials Register (CENTRAL/CCTR), Medline (1966 to July 2007), EMBASE (1980 to July 2007), CINAHL (1982 to July 2007), British Nursing Index (January 1984 to July 2007), AMED (1985 to July 2007), SIGLE (1980 to July 2007), and Dissertation Abstracts International (1861 to July 2007) were all searched using key words. Reference lists of all studies identified for inclusion and relevant reviews were also searched. In addition, relevant journals were hand searched and experts in the field of cancer-related fatigue were contacted.
Selection Criteria: Randomized controlled trials that investigated the effect of exercise on cancer-related fatigue in adults were included.
Data Collection and Analysis: Two review authors independently assessed the methodologic quality of studies and extracted data based upon predefined criteria. Where data were available, meta-analyses were performed for fatigue using a random-effects model.
Main Results: Twenty-eight studies were identified for inclusion (n = 2,083 participants), with the majority carried out on participants with breast cancer (n = 16 studies; n = 1,172 participants). A meta-analysis of all fatigue data, incorporating 22 comparisons, provided data for 920 participants who received an exercise intervention and 742 control participants. At the end of the intervention period, exercise was statistically more effective than the control intervention (standard mean difference = −0.23; 95% confidence interval, −0.33 to −0.13).
Authors' Conclusions: Exercise can be regarded as beneficial for persons with cancer-related fatigue during and after cancer therapy. Further research is required to determine the optimal type, intensity, and timing of an exercise intervention.
These summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (http://www.cochrane.org).