Written by Kerry Courneya, Ph.D., and Margaret McNeely, Ph.D.
What is Cancer?
According to the American Cancer Society (ACS), there are more than 100 different diseases that are classified as “cancer.” The common thread among these different types of cancers is that they all start as abnormal cells that grow out of control in some part of the body. The ACS estimates that more than 1.4 million Americans were newly diagnosed with cancer and more than a half million were expected to die of the disease in 2008. The three most common cancers occurring in men are prostate, lung and colorectal cancers; in women, breast, lung and colorectal cancers arethe three most common. Cancer may be treated by a number of methods, either alone or in combination. These treatments include surgery, radiation, chemotherapy, hormonal therapy and biological therapy.
How Exercise Helps
An increasing number of studies have examined the benefits of exercising during cancer treatment. Although the majority of studies have examined women with early-stage breast cancer, research evidence suggests that exercise can have a positive impact on body weight, overall fitness, muscle strength, flexibility and quality of life, as well as on symptoms such as pain and fatigue. A recent study by Kerry Courneya, Ph.D., and colleagues found benefits from exercise for chemotherapy completion. In the study, women with breast cancer participating in a resistance training program during chemotherapy had dose reductions and fewer delays in their chemotherapy treatments.
Physical Activity Recommendations
The optimal form of exercise training for cancer patients undergoing treatment still remains unclear. Research studies have generally examined moderate-intensity aerobic exercise, resistance exercise, and/or combined programs. Further research is needed to determine the best type, timing and intensity of exercise for the different types and stages of cancer. Despite these limitations, for the most part, exercise prescriptions have closely followed the published guidelines of the American College of Sports Medicine.
Individuals are potentially different in their responses to cancer treatment. Exercise programs may need to be modified to allow for “down” days in the treatment cycle. In the case of chemotherapy or biological therapy, this may mean avoiding or scaling back exercise on days when side effects from treatment are more pronounced. In the case of radiation therapy, exercise may need to be reduced, or in some cases avoided, toward the end of treatment and/or in the early weeks following treatment.
If an individual is not regularly active and wishes to start an exercise program during cancer treatment, they may need to start with low-intensity exercise, consisting of slow walks, and gradually progress exercise over time. If they will be receiving chemotherapy, it may be wise to wait one chemotherapy cycle to see the response to treatment prior to starting an exercise program.
Individuals undergoing cancer treatment should:
- Obtain approval from their oncologist (cancer doctor) before starting an exercise program.
- Have vital signs (temperature, pulse/heart rate, blood pressure, respiration rate) monitored regularly. If participating in moderate-to-vigorous exercise, have their blood pressure and heart rate monitored before, during and after exercise to ensure that participation in exercise is appropriate and safe.
- Exercise with a partner, caregiver or exercise professional for safety reasons.
- Avoid public fitness facilities and activities (e.g., swimming), where there may be an increased risk of exposure to viral and/or bacterial infection.
- Avoid swimming if undergoing radiation therapy treatments or if they have an indwelling catheter (a tube that goes in the body), such as a central venous catheter or peripherally inserted central catheter.
- Stop exercise and contact their doctor if they have any of the following symptoms during exercise or after an exercise session:
– Disorientation, dizziness, blurred vision or fainting
– Sudden onset of nausea, vomiting
– Unusual or sudden shortness of breath
– Irregular heart beat, palpitations, chest pain
– Leg/calf pain, bone pain, unusual joint pain or pain not caused by injury
– Muscle cramps or sudden onset of muscular weakness or fatigue
Although exercise may be an effective intervention for cancer patients undergoing treatment, it is important to recognize there may be factors that make it unwise to exercise. In these cases, exercise may be still beneficial; however, the risks may be higher, and close medical supervision may be required. According to the ACS, the following are specific precautions to be aware of during cancer treatment:
- Anemia (low red blood cell count): If the red blood cell count is low, the body’s ability to carry oxygen to the tissues is reduced. Exercise may need to be scaled back and possibly avoided.
- Neutropenia (low white blood cell count): If the white blood cell count is low, the body’s ability to fight infection is reduced. Exercise should be avoided if there is a fever above 100.4°F (>38°C).
- Thrombocytopenia (low platelet count): If platelet count is low, there is an increased risk of bruising and bleeding. Avoid contact sports or activities with high risk of injury or falling. Report any unusual bruising or symptoms, such as nose bleeds, to a doctor.
- Side effects such as vomiting and diarrhea, and symptoms such as swollen ankles, unexplained weight loss/gain, or shortness of breath with low levels of exertion may make exercise unsafe. Check with a doctor before exercising.
Research evidence suggests that individuals with cancer who follow recommended guidelines and observe specific precautions can safely exercise during cancer treatment.
View the full spring 2009 issue of the ACSM Fit Society® Page online.