New research shows that girls and young women who exercise regularly between the ages of 12 and 35 have a substantially lower risk of breast cancer before menopause compared to those who are less active. The study, by researchers at Washington University School of Medicine and Harvard University, appears in the online Journal of the National Cancer Institute.
In this report, the largest and most detailed analysis to date of the effects of exercise on premenopausal breast cancer, nearly 65,000 women were studied and it was found that those who were physically active had a 23 percent lower risk of breast cancer before menopause. In particular, high levels of physical activity from ages 12 to 22 contributed most strongly to the lower breast cancer risk.
“We don’t have a lot of prevention strategies for premenopausal breast cancer, but our findings clearly show that physical activity during adolescence and young adulthood can pay off in the long run by reducing a woman’s risk of early breast cancer,” says lead investigator Graham Colditz, M.D., associate director at Washington University School of Medicine and Barnes-Jewish Hospital. “This is just one more reason to encourage girls and young women to exercise regularly.”
One-fourth of all breast cancers are diagnosed in women before menopause. “You don’t have to be a marathon runner to get the risk-reducing benefits of exercise,” the authors add.