Exercise benefits younger women

Physically active premenopausal women significantly reduce their risk of breast cancer, according to research in the May 13 edition of the Journal of the National Cancer Institute. Many studies have shown an exercise benefit to postmenopausal women, but this new research shows that younger women also reduce their cancer risk. The research is part of the long-range Nurses Health Study and included 64,777 premenopausal women. Some details:

• The greatest risk reduction came from exercise between 12 and 22, with those 23 to 34 showing a slightly reduced benefit. Women over 35, in this study, gained no risk reduction, which contradicts other studies that show a benefit to lifelong exercise.

• Running 3.25 hours a week or walking 13 hours a week brings a 23 percent risk reduction.

NOTE: Hormone-negative breast cancer is most common among premenopausal women.