If you’ve been diagnosed with breast cancer, your focus may be on getting through treatment and letting things like fitness slide. But a growing body of evidence suggests that exercise is not only good for you now, it may also set you on the path to a healthier survivorship, staving off bone loss, improving heart health, and even helping to prevent a recurrence of your cancer.

In the past, “people would tell patients, ‘you’ll get really tired, you should just rest,’” says Eleanor M. Walker, MD, the director of breast services in the department of radiation oncology at Henry Ford Cancer Institute in Detroit.

Rest is important, says Dr. Walker —but not to the exclusion of exercise. “If you’re not exercising — and that includes your muscles as well as your heart — you lose function that you may never get back afterwards,” she says.

These days, some cancer treatment centers are weighing the positive evidence about exercise and breast cancer treatment, recovery, and survivorship and adding a prescription for exercise into the mix.

What’s more, the American Cancer Society, as well as the U.S. Centers for Disease Control and Prevention (CDC), recommends that all cancer survivors get 150 minutes of moderate or 75 minutes of vigorous physical activity, along with at least two strength-training sessions, each week.

Here are some of the cancer-related issues a workout can help with.

Exercise During Treatment

Treatment-related fatigue Up to 90 percent of patients receiving radiation and up to 80 percent of those receiving chemo experience a kind of fatigue characterized by weakness and lack of energy. An impressive roster of studies indicates that exercise can measurably improve the type of fatigue brought on by treatment. In a review published in March 2018 in the Breast Journal, researchers note that exercise (among other behavioral changes) is more effective than medications at managing fatigue. The researchers said that, unlike medication, exercise may get at the underlying causes for fatigue, rather than just offering temporary relief.
Lymphedema When lymph nodes are removed during breast cancer surgery, you may end up with swelling and pain because of a buildup of lymph fluid. “It used to be that we told women not to lift weights because we thought it caused lymphedema,” says Walker. “But data now shows that light weight lifting can actually prevent it.” A randomized controlled Australian study that appeared in the September 2013 Journal of Cancer Survivorship found that women with breast cancer–related lymphedema can safely lift even heavy weights without causing or worsening lymphedema. That said, if you’re just post-surgery, get clearance from your surgeon first.
Mood “Exercise releases endorphins, brain chemicals that make us feel better,” says Walker. “I encourage patients as they go through radiation treatments to experiment with the kinds of exercise that make them feel better — I ask them, ‘What used to make you happy when you were a kid?’” Whatever you choose to do — hitting the gym, a dance class, bowling, gardening, playing with kids or grandkids in the park — an effective, mood-boosting session should last at least 30 minutes at moderate intensity (you’ve broken a sweat but can still speak).

When Treatment Is Done

Menopausal symptoms “Premenopausal women often take tamoxifen, an anti-estrogen, for five years post-treatment, which can put them into menopause,” says Walker, triggering side effects like hot flashes and potentially accelerating bone loss. All these effects, she notes, can be mitigated with exercise. Exercise can help you maintain muscle strength as you age, which in turn helps you maintain bone health and avoid fractures. Similarly, many post-menopausal survivors take drugs called aromatase inhibitors. In research published in the December 2016 issue of the journal Obesity, women taking aromatase inhibitors who did 150 minutes a week of aerobic exercise plus twice-weekly strength-training sessions had lower body fat and higher lean body mass than women who did not. Walker says exercise may also help women who take aromatase inhibitors, which can cause joint pain, to stay on the medication. “If exercise helps these women lose weight and feel less pain, that means they often stay on the medication, and that improves their long-term prognosis.”
Heart health The American Heart Society recently issued a statement about the overlapping risk factors between heart disease — the number-one killer of women — and breast cancer. In fact, because of improvements in the detection and success in treating breast cancer, many more cancer survivors end up at risk for heart disease (simply thanks to aging). Their risk is higher if they have existing risk factors for heart disease (obesity, smoking). Plus certain cancer treatments can trigger cardiac complications that elevate risk. Exercise, particularly among older, previously sedentary or overweight women, can be the key to heart health. A study published in the Journal of Clinical Oncology in March 2018 found that breast cancer survivors who incorporated resistance training and aerobic exercise reduced their risk of heart disease by mitigating the effects of obesity and metabolic syndrome.
Cognition and memory Many breast cancer survivors report feeling foggy — it’s sometimes called “chemo brain” — after treatment, while others experience a decline in thinking, memory, and concentration, says Sheri Hartman, PhD, an assistant professor in the Department of Family and Preventive Medicine and a codirector of the diet and physical activity shared resource at the University of California in San Diego Moores Cancer Center. In a study Dr. Hartman and colleagues published in September 2017 in Cancer, breast cancer survivors who participated in a physical activity program showed a “significant improvement” in cognitive processing speed and other tests of memory and concentration.

Getting Started: How Do You Work Out With Cancer?

Around the country, there are a few exercise programs designed specifically for cancer patients and survivors. At Henry Ford’s ExCITE program (Exercise & Cancer Integrative Therapy Education), for instance, cancer patients are evaluated by exercise physiologists to determine their baseline fitness and create personalized plans for them. “Patients can work out at home, at their own gyms, or on-site at our cardiac rehab facilities,” says Walker. If you don’t have access to a similar program, check with a local YMCA or gym for a trainer who specializes in cancer patients.