Exercise may slash the risk of aggressive breast cancer in black women, according to a new study. Researchers at the Georgetown Lomardi Comprehensive Cancer Center and Boston University have determined that African American women who regularly engage in vigorous exercise have a 47 percent reduced risk of developing a range of treatment-resistant tumors. The findings may lead to new public health recommendations and prevention strategies.

Epidemiological data indicates that compared to white women, black women are significantly more likely to develop and die from so-called estrogen receptor-negative (ER-) breast cancer. This cancer type, which includes HER2-positive and triple negative tumors, is typically associated with poor prognosis and treatment resistance. The new study sought to determine whether vigorous exercise can help offset this elevated risk.

To investigate, the researchers looked at data compiled by the Black Women’s Health Study (BWHS) — an exhaustive, 20-year study designed to help health officials and scientists determine why African American women are at significantly greater risk of diabetes, stroke, lupus, hypertension, and certain types of breast cancer. Of the 59,000 women involved in the project, the researchers looked at 44,704 women above the age of 30.

According to the authors, the results suggest a strong correlation between vigorous exercise and a decreased risk of aggressive breast cancer. Subjects who reported three or more hours of exercise per week had a 47 percent lower risk of developing ER- cancer compared to subjects who reported an average of one hour per week.  “These findings are very encouraging,” researcher Lucile Adams-Campbell said in a press release. “Knowing that exercise may protect against breast cancers that disproportionately strike black women is of great public health importance.”

Although the study falls short of establishing a hard, causal relationship between exercise and cancer risk, it nonetheless provides strong evidence that sensible lifestyle choices may have invaluable health benefits. "We all want to do what we can to reduce our risk of disease and improve our health, and along with other well-known benefits, we now show that exercise can possibly stave off development of potentially lethal breast cancer in black women," Adams-Campbell added.

According to the National Institutes of Health (NIH), breast cancer is currently the second most deadly cancer among women, affecting over 200,000 and killing 40,000 each year. It is estimated that one in every eight women will develop the disease at some point in their life. While the cause remains unknown, risk factors include early puberty, late menopause, and certain genes. Lifestyle factors like calorie intake and alcohol consumption have also been implicated in higher risk for diagnosis.