May 22, 2008
Teenage Girls Who Exercise May Get Protection from Premenopausal Breast Cancer
Women have long been advised that exercise lowers the risk of premenopausal breast cancer. A study published by the Journal of the National Cancer Institute has found that starting exercise as young as 12-years-old provides some protection for later in life. The study tracked 64,777 nurses in the Nurses' Health Study II, asking about their leisure-time physical activities from age 12 to the present. During the six years of the study, 550 of them developed breast cancer. "The women who regularly engaged in high amounts of physical activity during adolescence and early adulthood had a lower risk of premenopausal breast cancer than women who engaged in less activity," the study found. The physically active women were 23 percent less likely to develop cancer, and the biggest impact was regular exercise from ages 12 to 22. Women who exercised vigorously (for example running) for three hours and 15 minutes per week or who walked for 13 hours had the lowest risk. The study may be found at: http://jnci.oxfordjournals.org/cgi/content/abstract/100/10/728.
