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, reports a new study in the Journal of the National Cancer Institute. In the largest and most detailed analysis to date of the effects of exercise on premenopausal breast cancer, the study found that 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, at the Washington University School of Medicine. "This is just one more reason to encourage young girls and women to exercise regularly."
The study found the age-adjusted incidence rates for invasive breast cancer dropped from 194 cases per 100,000 person-years in the least active women to 136 cases in the most active. The levels of physical activity reported by the most active women were the equivalent of running 3.25 hours a week or walking 13 hours a week. The benefit of exercise was not linked to a particular sport or intensity but related to total activity. "You don't have to be a marathon runner to get the risk-reducing benefits of exercise," Colditz noted.
Related:
Exercise Keeps Breast Cells Working Well
Exercise And Breast Cancer Prevention: It's Never Too Late To Start
Source: Washington University School of Medicine
