While exercise confers cardiovascular and other health benefits throughout life, women who engage in regular physical activity in their 40s may significantly slash their postmenopausal breast cancer risk.  Tricia M. Peters, from the US National Cancer Institute (Maryland, USA), and colleagues studied 118,899 postmenopausal women enrolled in the National Institutes of Health-AARP Diet and Health Study, in which study participants, ages 50 to 71 years, were surveyed as to participation in physical activity in the ten years prior to menopause.  The researchers found that postmenopausal women who maintained more than 7 hours per week of higher intensity activity over the 10-year period prior to entry into the study were 16% less likely to develop breast cancer.   The team concludes that: “: A high level of recent physical activity of moderate-to-vigorous intensity is associated with reduced postmenopausal breast cancer risk.”