Morgan Wharton and Annika Schmid, Cancer Prevention and Treatment Fund
You may have heard that regular exercise can reduce your risk of developing cancer, but did you know it’s also good for cancer patients who are undergoing or have completed treatment?
Is Exercise Good for Everyone Diagnosed with Cancer?
Exercise has proven benefits for cancer patients, ranging from improved fitness and higher quality of life to reduced rates of recurrence and a longer life.[1-9] What we know about exercise and cancer mostly comes from studying patients with breast or colon cancer, but there’s reason to believe that there are benefits of exercise for men and women suffering from all types of cancer, even cancer as advanced as Stage III.[3, 7]
The best news of all: It doesn’t matter if you were fit before you got diagnosed. Whether or not you exercised before has no bearing on what exercise can do for you during and after treatment.[3, 4, 6] So, it’s never too late to use exercise to fight cancer. If you’re coping with cancer or its aftermath, now is the time.
What Does the Science Show about Exercise for Cancer Patients?
Many studies have shown that exercise is beneficial to cancer patients, but no one is sure exactly why. Earlier studies suggested that exercise may help women avoid breast cancer or a recurrence of it by decreasing female hormones that feed cancer in the breast,[10-11] or by lowering inflammation in the body, a suspected contributor to many diseases. In 2014, a study was published that provides a new possible explanation for how exercise helps the body fight cancer. Researchers looked at irisin, a protein released from muscles after exercise, to see how it would affect breast cancer cells and healthy breast cells in test tubes. What they found was that when breast cancer cells came into contact with irisin, they started to self-destruct in a programmed way. While the exercise protein reduced the number of malignant cells and their ability to move around, it left the healthy cells unharmed! The researchers also found that irisin made Doxorubicin, a chemotherapy drug commonly given to breast cancer patients, more effective at killing cancer cells. Though this study did not look at what happens to cancer cells in actual patients after they exercise, it could help explain why other studies have found that cancer patients who are physically active feel better during treatment and are less likely to have their cancer come back.
A study from 2020 found that exercise is beneficial for preventing cancer deaths. It examined how active people were per day, and found that people who were more active were less likely to die from cancer by a follow-up 6 years later. However, the study did not include people who were undergoing cancer treatment when the study was measuring physical activity, which makes sense since cancer treatment can drastically reduce the ability to exercise. This means that the results of the study are not specifically about people undergoing cancer treatment.
Studies that did look at patients focused on those beginning exercise (such as walking or aerobic exercise with weight training) somewhere between 2 weeks and 1 year after completing cancer treatment. In these studies, treatment could include surgery, chemotherapy, radiation, or a combination of these therapies.[1, 2, 3, 4, 6, 7, 8] Some studies also examined the effects of exercise during cancer treatment.[5, 9]
Less Body Fat and Better Immune System:
Studies have shown that in cancer patients, exercise during or after treatment reduces fat and improves body mass index (BMI).[2, 6, 9] Exercise lowers blood pressure, boosts the immune system, and increases bone mineral density.[6, 8, 9] Denser bones means fewer fractures.
As expected, cancer patients who exercise regularly during and after treatment reported increases in strength, walking ability, aerobic capacity, and flexibility.[2, 6, 9]
Less Fatigue and Fewer Side Effects from Treatment:
Cancer patients who had completed treatment reported fewer negative side effects from treatment once they began to exercise regularly. Patients who exercised during treatment reported less nausea and less difficulty sleeping. The most commonly reported improvement was reduced fatigue. [6, 8, 9] In addition, a study published in 2021 indicates that exercise may also help relieve “chemo brain” (also known as chemo fog), which is a common side effect for cancer patients undergoing chemotherapy. Common symptoms of chemo brain are having trouble with learning new tasks, remembering names, paying attention, and concentrating. The study found that patients who did either 2.5-5 hours of moderate intensity exercise (like brisk walking) per week or who did 1.5-2.5 hours of high intensity exercise (such as running) per week in the week before starting chemotherapy, within 1 month of completing chemotherapy, and 6 months after completing chemotherapy were less likely to report “chemo brain” symptoms than patients who did not exercise. Chemo brain can be upsetting and debilitating, affecting more than 75% of breast cancer patients undergoing chemotherapy, for example.
Better Quality of Life:
In addition to the physical health benefits of exercise, cancer patients who exercised also reported improved mental and emotional well-being. Patients who exercised during treatment and those who began to exercise afterwards frequently reported an increase in quality of life. Patients who began to exercise regularly after treatment experienced less anxiety and a renewed “fighting spirit.” Cancer patients over the age of 80 who exercised regularly during their weeks or months of treatment reported less loss of memory.
Reduced Risk of the Cancer Coming Back:
Because exercise improves the immune system, cancer patients who exercise regularly lower their risk of the cancer returning.[1, 2, 3, 8] Patients who exercise are less likely to die from cancer and are more likely to live longer than patients who don’t exercise.
What Kind of Exercise Should I Do?
Aerobic activity of light to moderate intensity was the most common type of exercise in the studies of cancer patients.[2, 3, 6, 8, 9] Combining aerobic exercise with walking and resistance training (such as weight lifting or using resistance bands) led to greater health benefits than aerobic activity alone.[2, 6, 8]
Most studies used Metabolic Equivalent (MET) hours to measure physical activity by level of intensity. MET hours measure the energy output of various activities compared to the energy used by the body when at rest. Activities that require more effort have a higher MET score than activities with lower intensities. One study suggested that 18-27 MET hours per week represents the ideal rate of exercise, because that group showed the lowest rate of recurrence and more activity did not lead to increased benefits. Having a MET score comparable to 6 or more hours of walking in a week showed a 47% higher chance of survival without recurrence. Click here for a chart of various activities and their MET hour equivalent, so you can calculate your weekly exercise in MET hours and maximize your benefits from exercise.
Walking can improve the health of cancer patients. Studies estimate that the greatest benefit from walking is seen in patients who walk at an average speed(a 20 minute mile) for 3-5 hours weekly. Patients who walked just 1 hour per week, regardless of walking speed, showed improvements over the group of patients who reported no physical activity in a week.
To get the most out of exercise, you need to make it a habit—something you commit to for the long-term. That’s why it is better to start small, with easily achievable changes like using the stairs regularly instead of the elevator or walking each evening after dinner. Remember not to set unrealistic goals, because it is better to start small and keep it up than to try to do too much and give up. Don’t miss the chance to get at least some benefit from this easy, free strategy to fight cancer.
The Bottom Line
Exercise helps individuals who are undergoing cancer treatment and those who have completed cancer treatment. Cancer patients who exercise regularly during and after treatment can expect fewer side-effects from treatment, including less fatigue, fewer problems with concentration and memory, and better overall fitness and health. Patients who exercise are less likely to experience a return of cancer in the future and are more likely to live longer, healthier lives.
You should try to walk at least six hours a week at an average pace (about 1 mile per 20 minutes).
Even minimum exercise, like walking one hour per week, can improve the health of cancer patients who have completed treatment, compared to cancer patients who do not exercise at all. The benefits from exercise can be seen in all cancer patients, regardless of whether or not they exercised regularly before they were diagnosed with cancer. It’s never too late to begin to exercise and improve your health!
- Barbara Sternfeld, E.W., Charles P. Quesenberry, Jr., Adrienne L. Castillo, Marilyn Kwan, Martha L. Slattery, and Bette J. Caan, Physical activity and risk of recurrence and mortality in breast cancer survivors: Findings from the LACE study. Cancer Epidemiology, Biomarkers & Prevention, 2009. 18(1): p. 87-95.
- Daniel Y T Fong, J.W.C.H., Bryant P H Hui, Antoinette M Lee, Duncan J Macfarlane, Sharron S K Leung, Ester Cerin, Wynnie Y Y Chan, Ivy P F Leung, Sharon H S Lam, Aliki J Taylor, Kar-keung Cheng, Physical activity for cancer survivors: Meta analysis of randomised controlled trials. British Medical Journal, 2012. 344(70).
- Jeffrey A. Meyerhardt, D.H., Donna Niedzwiecki, Donna Hollis, Leonard B. Satz, Robert J. Mayer, James Thomas, Heidi Nelson, Renaud Whittom, Alexander Hantel, Richard L. Schilsky, and Charles S. Fuchs, Impact of physical activity on cancer recurrence and survival in patients with stage III colon cancer: Findings from CALGB 89803. Journal of Clinical Oncology, 2006. 24(22): p. 3635-3541.
- Jeffrey A. Meyerhardt, E.L.G., Michelle D. Holmes, Andrew T. Chan, Jennifer A. Chan, Graham A. Colditz, and Charles S. Fuchs, Physical activity and survival after colorectal cancer diagnosis. Journal of Clinical Oncology, 2006. 24(22): p. 3527-3534.
- LK Sprod, S.M., W Demark-Wahnefried, MC Janelsins, LJ Peppone, GR Morrow, R Lord, H Gross, KM Mustian, Exercise and cancer treatment symptoms in 408 newly diagnosed older cancer patients. Journal of Geriatric Oncology, 2012. 3(2): p. 90-97.
- Margaret L. McNeely, K.L.C., Brian H. Rowe, Terry P. Klassen, John R. Mackey, Kerry S. Courneya, Effects of exercise on breast cancer patients and survivors: A systematic review and meta analysis. Canadian Medical Association Journal, 2006. 175(1): p. 34-41.
- Michelle D. Holmes, W.Y.C., Diane Fesknich, Candyce H. Kroenke, Graham A. Colditz, Physical activity and survival after breast cancer diagnosis. Journal of the American Medical Association, 2005. 293(20): p. 2479-2486.
- Rosalind R. Spence, K.C.H., Wendy J. Brown, Exercise and cancer rehabilitation: A systematic review. Cancer Treatment Reviews, 2009. 36: p. 185-194.
- Ruud Knols, N.K.A., Daniel Uebelhart, Jaap Fransen, and Geert Aufdemkampe, Physical exercise in cancer patients during and after medical treatment: A systematic review of randomized and controlled clinical trials. Journal of Clinical Oncology, 2005. 23(16): p. 3830-3842.
- Key T, Appleby P, Barnes I, Reeves G. Endogenous sex hormones and breast cancer in postmenopausal women: reanalysis of nine prospective studies. J Natl Cancer Inst. Apr 17 2002;94(8):606-616.
- McTiernan A, Tworoger SS, Ulrich CM, et al. Effect of exercise on serum estrogens in postmenopausal women: a 12-month randomized clinical trial. Cancer Res. Apr 15 2004;64(8):2923-2928.
- Friedenreich CM, Neilson HK, Woolcott CG, et al. Inflammatory Marker Changes in a Yearlong Randomized Exercise Intervention Trial among Postmenopausal Women. Cancer Prevention Research. January 1, 2012 2012;5(1):98-108.
- Gannon NP, Vaughan RA, Garcia-Smith R, Bisoffi M, Trujillo KA. Effects of the exercise-inducible myokine irisin on malignant and non-malignant breast epithelial cell behavior in vitro. Int J Cancer. Feb 15 2015;136(4):E197-202.
- Gilchrist SC, Howard VJ, Akinyemiju T, Judd SE, Cushman M, Hooker SP, Diaz KM. Association of Sedentary Behavior With Cancer Mortality in Middle-aged and Older US Adults. JAMA Oncology. 2020;6(8):1210–1217.
- Elizabeth A. Salerno, Eva Culakova, Amber S. Kleckner, Charles E. Heckler, Po-Ju Lin, Charles E Matthews, Alison Conlin, Lora Weiselberg, Jerry Mitchell, Karen M. Mustian, Michelle C. Janelsins. Physical Activity Patterns and Relationships With Cognitive Function in Patients With Breast Cancer Before, During, and After Chemotherapy in a Prospective, Nationwide Study. Journal of Clinical Oncology. 2021. https://ascopubs.org/doi/full/10.1200/JCO.20.03514.