Haley JS, et al. - The Women In Steady Exercise Research (WISER) Sister study was undertaken to evaluate the impacts of a dosed, moderate to vigorous, aerobic exercise intervention on levels of inflammation in premenopausal women who were at high risk of developing breast cancer. Participants in the study were randomized to control (< 75 minutes per week; 41 patients), low-dose exercise (150 minutes per week; 38 patients), or high-dose exercise (300 minutes per week; 37 patients) groups. In a population of healthy women who were at high risk of developing breast cancer, moderate to vigorous aerobic exercise seemed to increase levels of proinflammatory biomarkers in a dose-dependent manner. Findings suggested that the mechanism of reduced risk of breast cancer found in physically active individuals may not result from reduced levels of inflammation in healthy premenopausal women.