Brisk Walking Reduces Breast Cancer Risk in Postmenopausal Women

Women who exercise are at reduced risk for breast cancer. In the Women's Health Initiative Observational Study of almost 75,000 postmenopausal women (age range, 50-79), researchers sought to define the association between breast-cancer risk reduction and exercise intensity and to determine whether risk reduction requires lifelong exercise. Data were obtained regarding physical activity at ages 18, 35, and 50, in addition to current physical activity.

During a mean 4.7 years of follow-up, women who currently exercised at an intensity equivalent to brisk walking for 1.25-2.50 hours weekly had a significant 18% reduction in breast cancer risk, compared with sedentary women. Among women who walked briskly for more than 10 hours weekly, the risk …