If we had a pill that conferred all the benefits of exercise, physicians would prescribe it to every patient. Our health care system would find a way to make sure that every patient had access to this “wonder drug.”
~Dr. Robert E. Sallis
Remember last week I talked about the idea of prescribing exercise as a treatment, in the same way we would prescribe a drug? This week, that vision became closer to a reality in the prevention and treatment of one of the most significant chronic diseases we all face.
Unfortunately, cancer touches most of us. The good news is that cancer deaths are actually declining in the western world due to advances early detection and treatment. Nonetheless, cancer continues to be the second leading cause of mortality worldwide.
Like other chronic illnesses, many cancers can be prevented and better managed with lifestyle changes. Not surprisingly, exercise has emerged as a powerful weapon in cancer prevention and treatment. This week, three very significant research articles were published, which summarized the work of a 17-member panel of worldwide exercise oncology experts. The panel was interested in the relationship between cancer care and physical activity.
The panel reviewed the scientific research looking at almost 1.5 million pooled research subjects. Their review focused on the use of exercise as a means of prevention, in the management of symptoms from cancer treatment, and for supportive care of cancer survivors . From this review, the panel also made recommendations for translating evidence into practice for those working in cancer care.
Here are the important points to know:
Approximately one-quarter of the world’s population is considered to be physically inactive, which increases their risk of developing cancer. According to the Sedentary Behaviour Research Network, “…physical inactivity is now the 2nd leading cause of death in the U.S. and the 4th worldwide. This represents about 5.3 million deaths per year, which is equivalent to the 5 million deaths attributed to tobacco usage.” If inactivity is so detrimental and exercise is such a powerful preventive health tool, how do we get people more active? Let’s start with light physical activity.
Also sometimes called “utility activity”, this is the type of movement that happens throughout the day. Simple daily movement has emerged as an important part of the chronic disease prevention puzzle. As long stretches of sitting time crowd out opportunities for movement, prolonged time seated is considered a risk unto itself (even if you are getting other forms of exercise). For example, researchers report that there is a 36% increased risk of developing endometrial cancer when comparing sedentary women to those who do regular moderate to vigorous level exercise.
Sedentary time has been implicated in not only certain types of cancers, but also in “all cause” mortality, type II diabetes, and cardiovascular disease. Take home message: To lower your overall risk of chronic disease, start by breaking up sitting time throughout the day and try to get more movement wherever possible (e.g., taking the stairs instead of the elevator).
The next step is to focus on regular exercise. We now have strong evidence that regular exercise lowers your risk of developing seven common types of cancer, which includes colon, breast, endometrial, kidney, bladder, esophagus and stomach. To be clear, the word or concept of exercise differs from physical activity (which is simply movement using your skeletal muscles that causes you to expend some energy). Exercise is a type of physical activity that is structured, planned, and usually takes place for a reason (like improving your health). This is where the idea of having sessions of moderate to vigorous physical activity for thirty minutes or more (structured, planned) comes in. Think about how you can plan regular sessions of exercise into your week. I’ll talk more about the best types and amounts for improving cancer outcomes below.
After reviewing the related research, the expert panel concluded that exercise was generally safe for those going through treatment (with the caveat that many of the exercise tolerance findings were based on studies of those with breast and prostate cancer). Here are their recommendations based on strong evidence in the use of exercise for those receiving treatment for cancer:
Moderate intensity aerobic activity (swimming, running, brisk walking, cycling) three times a week, or aerobic and resistance training twice a week, can reduce anxiety, fatigue, symptoms of depression, and improve physical function in cancer patients. Neither anxiety nor depression appear to be treated by resistance training alone. Unlike the results of studies of cancer patients with anxiety and fatigue, higher amounts of aerobic exercise seem to be more effective at reducing depressive symptoms in research participants.
Those with lymphedema, or the swelling of the arms and legs related to cancer treatment, can participate in regular exercise, but should see an exercise professional for an individualized and supervised prescription.
There is also moderate evidence that bone health in cancer patients can be improved by specific types of exercise (e.g., a 1-yr supervised program of combined moderate-vigorous intensity resistance plus high-impact training). Simple aerobic activity (walking) did not appear to have a significant impact on bone density. Because of the increased risk for osteoporosis in cancer survivors, women at risk for bone fragility or falls should work with their doctor and an exercise specialist who can best design an individualized program.
The panel recommended that for cancer survivors, incorporating regular exercise can help improve survival rates, especially after a diagnosis of breast, colon, and prostate cancer. Exercising to reduce other risks may be just as important for longevity; for example, some types of cancer treatment can also increase your risk of developing cardiovascular disease.
When looking at the “strong” evidence category outlined by the expert panel, cancer outcomes can be improved by exercising three times a week for 30 minutes or more, including twice a week of resistance training (one exercise per major muscle group, with 8-15 repetitions in sets of two).
If you are going through cancer treatment and want some guidance, check out this great handout from the Exercise is Medicine program. You can also print this simple prescription page to get some direction from your physician.
The evidence for the role of exercise in chronic disease reduction and treatment is crystal clear. My next step in promoting exercise for health might be buying myself a megaphone. 😊 Exercise is one of the best medicines that you will ever take. Period. Take it regularly and often and, please, start as soon as possible.
Your sister in health,
 Lynch B, Mahmood S, Boyle T. (2018). Sedentary behaviour and cancer. Sedentary Behaviour Epidemiology.
 Patel et al. (2019). American College of Sports Medicine Roundtable Report on Physical Activity, Sedentary Behavior, and Cancer Prevention and Control. Medicine & Science in Sports & Exercise. (51). 2391.
 Campbell et al. (2019). Exercise Guidelines for Cancer Survivors. Consensus Statement from International Multidisciplinary Roundtable. Medicine & Science in Sports & Exercise. (51). 2375.
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