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.

Regular exercise does more than improve fitness and boost mood. Research shows that physical activity may also help reduce breast cancer risk and improve outcomes after a diagnosis.

While scientists are still working to understand exactly how exercise influences breast cancer development, studies consistently show that physically active women tend to have lower breast cancer risk than those who are not. Researchers believe this relationship is driven by several factors, including body weight, inflammation, hormone levels, and overall metabolic health. Among these factors, body weight has emerged as one of the strongest and most extensively studied links between lifestyle and breast cancer risk.

Understanding the link between obesity and breast cancer

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 2026 statistics attribute rising incidence rates of breast cancer to the increasing prevalence of excess body weight.

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.

Actionable lifestyle changes to protect your breast health

The good news is that studies have consistently shown that making lifestyle changes, including maintaining a healthy diet and 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. Current estimates suggest that approximately one-third of breast cancer cases could be prevented through these targeted lifestyle interventions, which prioritize metabolic health, lean muscle mass, and sustained weight management. So, it’s not just about losing weight, it’s also about building lean muscle mass.

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. Their research includes:

• Investigating the key discovery that obesity and normal-weight metabolic dysfunction are associated with breast fat inflammation, tumor growth, and breast cancer recurrence.
• Developing a series of diet and exercise interventions aimed at reversing the tumor-promoting effects of metabolic dysfunction.
• Examining the effect of a combination of diet, exercise, and anti-inflammatory medication in reducing the obesity-breast cancer link.
• Increasing our understanding of the pathways whereby exercise could lower breast cancer risk and identifying new targets for the development of drugs that could prevent breast cancer.
• Launching the first-ever clinical trial to test the immediate effects of exercise on breast cancer biomarkers related to inflammation and blood vessel formation.
• Examining the importance of weight loss and exercise after breast cancer; this follows the discovery that movement, good nutrition, and guided weight loss are effective strategies to improve outcomes and reduce the risk of recurrence.

The synergistic role of diet and physical activity

Diet and exercise are linked in how they regulate systemic inflammation and overall metabolic health. Ultimately, understanding the complex relationship between physical activity, nutrition, obesity, and breast cancer development can lead to the creation of highly personalized breast cancer prevention strategies. Advancing this knowledge allows clinicians to devise specific, combined diet and exercise plans tailored to an individual’s unique biological and metabolic profile.

Frequently asked questions

Does strength training help with breast cancer risk? 

Strength training appears to be an important part of a healthy exercise regimen which helps lower breast cancer risk. When combined with aerobic activity, strength training helps maintain lean muscle mass and improves overall metabolic function.

Is exercise safe during or after breast cancer treatment?

It depends on each individual’s specific treatment, cardiotoxic exposures, treatment phase, and general health. Determining whether it’s safe to exercise during or after breast cancer treatment requires coordinated guidance from a multidisciplinary cancer care team.

Do lifestyle interventions strictly apply to postmenopausal women?

While obesity profoundly impacts postmenopausal risk profiles, establishing consistent metabolic and physical activity habits across all life stages, including childhood and premenopausal years, is vital for breast cancer risk reduction.