A recent study performed by the Epidemiology Research Program at the American Cancer Society found that postmenopausal women who walked at least seven hours per week, usually about an hour a day, had a 14% less risk of developing breast cancer than those who walked fewer than three hours per week.
The study also found that women who were most active, meaning they sweat vigorously for up to ten hours per week through exercise, had a 25% lower risk of developing breast cancer than those that exercised the least. Alpa V. Patel, a senior epidemiologist with the American Cancer Society says, “Walking is an easy, inexpensive type of exercise. Almost everyone can do it. And for this population of postmenopausal women, it provided a very significant reduction in the risk of breast cancer.”
Exercise, in general, lowers the risk of breast cancer for both postmenopausal and premenopausal women. A study that looked at younger women performed by the School of Public Health at the University of Minnesota studied sedentary, premenopausal women. This study found that exercise altered the levels of metabolites in the body which may decrease the chance of breast cancer.
Exercise is not the ultimate answer to preventing breast cancer; some women in Dr. Patel’s study who walked regularly still developed breast cancer, and some who did not exercise did not get breast cancer. But, Dr. Patel encourages exercise and says “Physical exercise, and especially walking, is so simple and so accessible to most women. And statistically, they do seem to reduce breast cancer risk. So why not?”