Effects of physical activity on endogenous sex hormones in postmenopausal women

Background: It is hypothesized that physical activity lowers postmenopausal breast cancer risk at least in part via hormonal pathways. Thus, we investigated whether recent physical activity was associated with lower circulating levels of endogenous sex hormones after menopause. Methods: We conducted a cross-sectional study in 1260 postmenopausal women recruited as controls in the population-based breast cancer case-control study MARIE. Serum concentrations of estrone, estradiol, androstenedione, testosterone, and sex-hormone-binding-globulin (SHBG) were measured, and their associations with different physical ac…