Exercise and Breast Cancer: How Regular Movement Can Help Reduce Your Risk

Cardio and strength training aren’t just good for boosting your mood and keeping weight off. Here’s how breast cancer and exercise are linked.

Obesity is a major contributor to the nation’s cancer toll and is quickly overtaking tobacco as the leading preventable cause of cancer, according to the American Society of Clinical Oncology, making a healthy diet and regular exercise that much more important.

Exercise has many benefits—but chief among them is maintaining a healthy weight. Regular exercise helps reduce the risk of obesity-associated diseases, including cardiovascular disease, diabetes, and many types of cancer, including breast cancer.

Breast cancer, exercise, and body weight explored

Breast cancer and obesity are both on the rise worldwide and, interestingly, the two diseases are connected. Obesity can significantly increase a woman’s risk of breast cancer after menopause, according to the National Cancer Institute. Furthermore, women who are obese at the time of diagnosis have a 30 percent higher chance of dying from breast cancer or other causes in the years following their diagnosis. The American Cancer Society’s 2019 statistics attribute rising incidence rates of hormone receptor (HR)–positive breast cancer—the most common type of breast cancer—to the increasing prevalence of excess body weight.

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Remarkably, even dietary choices in childhood and adolescence can have an impact. Studies by BCRF researchers Drs. Graham Colditz, Walter Willett, and others have shown that being overweight early in life increases a woman’s risk of benign breast disease, which can increase her chance of future breast cancer.

The good news is that studies have consistently shown that making lifestyle changes including keeping a healthy diet, losing weight, and doing moderate-intensity exercise—just 150 minutes a week or more of aerobic exercise and strength training—can play a role in preventing breast cancer and improving prognosis after a breast cancer diagnosis. It is estimated that a third of breast cancers could be prevented with lifestyle choices, particularly those that help to maintain a healthy weight, including eating a balanced diet and exercising.

Unraveling the obesity-breast cancer connection to improve outcomes

How does exercise reduce cancer risk? Although the evidence is clear, we do not yet fully understand the connection between exercise, breast cancer risk, and weight. BCRF investigators are working to unravel the biologic mechanisms underlying this relationship and develop effective intervention strategies.

• Drs. Andy Dannenberg and Neil Iyengar have identified inflammatory markers that may predict risk of breast cancer, even in women of normal weight.
• A study, led by Dr. Stephen Hursting, is examining the effect of a combination of diet, exercise, and anti-inflammatory medication in reversing breast cancer risk.
• Dr. Anne McTiernan has launched the first-ever clinical trial to test the immediate effects of exercise on breast cancer biomarkers related to inflammation and blood vessel formation.
• Drs. Melinda Irwin and Vered Stearns are looking at the importance of weight loss and exercise after breast cancer, and early findings have shown that movement, good nutrition, and guided weight loss are effective strategies to improve outcomes and decrease the risk of recurrence.

Ultimately, understanding the interplay between breast cancer, diet, exercise, and weight loss could lead to the development of personalized and more effective prevention strategies, like specific diet and exercise plans.