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Benefits of Exercise Oncology Studied in Breast Cancer Patients


Harvard Medicine Magazine

The oars slice in and out of the water in unison as the boat glides downstream. To an observer, it looks like any other group of rowers enjoying a sunny day on the Charles River. But this all-female team of athletes has more than their love of rowing in common: They are all breast cancer survivors, bound together by their desire to stay strong and active.

These women, and their peers in boats across the country, have long understood through lived experience that regular exercise has powerful effects on both the bodies and minds of people with cancer. Today, science is finally catching up with them.

Just a few decades ago, advice to cancer patients, particularly those undergoing chemotherapy, centered on rest: Take it easy. Avoid strenuous activity, especially aerobic exercise. At the time, the recommendation seemed logical. Allowing the body to rest might also allow it to heal, experts thought, while physical activity might worsen fatigue, pain, and other symptoms.

This thinking began to change in the late 1980s, when a pair of oncology nurses at The Ohio State University undertook what was then a radical experiment. Curious to see whether conventional wisdom on exercise avoidance held true, they randomly sorted forty-five breast cancer patients who were undergoing chemotherapy into a group that participated in ten weeks of aerobic exercise training or into a control group. The findings of this landmark study were stunning: Not only was exercise safe and feasible during cancer treatment, it was also associated with improvements in weight, body composition, and nausea symptoms. The small trial served as a catalyst for future investigations, ultimately leading to a new field of study: exercise oncology.

In 2010, researchers and clinicians gathered at an interdisciplinary meeting to review the evidence on the safety of exercise in people living with cancer. The resulting American College of Sports Medicine (ACSM) Roundtable report—one of the first of its kind—advised cancer survivors to avoid inactivity.

Eight years later, the roundtable met again to assess the data; that assessment led the group to expand its recommendations to include the role of exercise in cancer prevention, control, and survivorship. The guidelines offer a powerful prescription for people with cancer. The evidence to support these guidelines is overwhelmingly reassuring: Studies suggest that regular physical activity is associated with fewer or milder side effects from chemotherapy, improved quality of life, and even lower odds of cancer recurrence and mortality. While research continues, leading investigators in the field say that every physician and other health care provider should consider prescribing exercise to their patients with cancer.

“We’re at the point where we know exercise is an evidence-based treatment with robust effects,” says Kathryn Schmitz, a researcher at the Penn State Cancer Institute who chaired the ACSM’s roundtables. “If we don’t prescribe it, when does that become malpractice?”

Weighty issues Since exercise oncology’s infancy, much of the research in the field has focused on breast cancer. That’s largely because of the prevalence of the disease, which, according to a 2020 NIH report, is the most common type of cancer among women in the United States. It also affects about 1 percent of men and can occur in transgender and nonbinary people assigned female at birth.

As with some other cancers, the conditions of overweight or obesity can heighten the risk for breast cancer in postmenopausal women. Indeed, one recent meta-analysis of eighty-two studies found that the risk of dying from breast cancer was 35 percent higher among women who were affected by obesity at the time of their diagnosis, compared to the mortality risk for women who were within standard weight ranges.