Exercise Gains Traction as a Way to Fight Cancer

Exercise is a potent weapon against cancer.

Research in the fast-growing field of exercise oncology has left little doubt that staying physically active improves symptoms and side effects during cancer treatment. And there is now solid evidence that exercise reduces the risk for some cancers and lowers the odds of dying if you are diagnosed with certain forms of the disease. Previous finding shows that breast cancer patients having chemotherapy who exercised regularly had less fatigue, nausea, and disability from the treatments.

In 2019, Kathryn Schmitz, director of the Oncology, Nutrition, and Exercise Group at the Penn State Cancer Institute, found that exercising during and after treatment for cancer eases fatigue, anxiety and depression, while improving quality of life and physical function, i.e. the ability to go about a normal day.

Meanwhile, studies strongly suggest that exercise lowers the risk for seven forms of cancer: bladder, breast, colon, endometrial, esophageal, kidney and stomach.

There are also intriguing clues that exercise helps prevent lung, blood, head and neck, ovarian, pancreatic, and prostate cancers, too. And exercising appears to reduce the risk of dying in people diagnosed with breast, colorectal and prostate cancers, in the range of 40% to 50%.

Schmitz points out that exercise reduces levels of inflammation and insulin, which are linked to some cancers.

Also, exercise induces angiogenesis, or the creation of new blood vessel, which could mean that more blood-driven anti-cancer medicine can be delivered to malignant tumors.

“Exercise may actually change the potency of chemotherapy,” says Schmitz.

Immune function also plays a role. While cancer weakens the immune system, a single bout of exercise produces a flood of defender immune cells, says Michael Gustafson, scientific director of the Nyberg Human Cellular Therapy Laboratory at the Mayo Clinic’s Arizona campus.

Gustafson found that pedaling full-speed on a stationary bike for 10 minutes can boost tumor fighters called natural killer cells by 10 times; protective T and B cells rise in the blood, too.

By using exercise to help cancer patients build up bigger armies of defender cells, Gustafson believes that it may be possible to make powerful immunotherapy treatments work better. Those treatments “teach” a patient’s own immune cells to attack tumors.

It is also well-known that body fat makes the hormone estrogen, which can cause some forms of breast cancer, says Betsy O’Donnell, director of the Lifestyle Medicine Clinic at Massachusetts General Hospital in Boston. Luckily, exercise, along with cutting calories, helps reduce body fat, a concern for many breast cancer patients, who often gain weight during treatment.

Research shows that aerobic exercise (such as walking, jogging, or cycling) and strength training (such as lifting weights or using resistance bands) can benefit cancer patients.

A 2007 study involving 242 women with breast cancer who were about to begin chemotherapy found that aerobic exercise improved patients’ self-esteem and reduced body fat, while resistance training helped build muscle and made them more likely to finish their treatment.

Not all cancer survivors are eager to hit the gym during or soon after the rigors of treatment, so tailoring the intensity of an exercise prescription to each patient is essential, says O’Donnell.

Walking is perhaps the most popular option many of her patients choose, particularly since many people have been avoiding gyms due to the COVID-19 pandemic. She recommends building up to at least 150 minutes of walking per week, maintaining a pace that allows you to talk, but not sing.