Effects of exercise on circulating levels of sex hormones in overweight and obese postmenopausal women: A systematic review

Objective. - This study aimed to examine the evidence regarding the regulatory role of exercise in circulating levels of sex hormones in overweight and obese postmenopausal women. News. - Exercise has shown to be an effective non-pharmacological tool in obesity and breast cancer prevention. Sex hormones have been proposed as a potential link by which exercise may modulate obesity and breast cancer after menopause, however, the response of sex hormones as a metabolic pathway responsible for the connection between both pathologies are not entirely understood. An extensive search was performed using PubMed, Medline, Scopus and SPORTDiscus databases for the period from inception of each database to May 2018. A total of 778 studies were found in the search. Of these, 9 met the inclusion criteria and were further analyzed. Despite the different exercise protocols performed, most studies found a decrease in circulating levels of estrone and estradiol, and an increase in sex hormone-binding globulin (SHBG). However, when the effect of exercise on these sex hormones was compared to an unexercised control group, conflicting results were obtained. A reduction in body mass was reported in those studies in which exercise caused a significant effect on estrone, estradiol and SHBG compared to a control group. Conclusion. - These results suggest that exercise-induced weight loss and the type of exercise performed may to be critical factors in the modification of the circulation expression of some sex hormones. Further studies are required to elucidate the most effective exercise dose to restore sex hormones homeostasis as potential obesity-breast cancer nexus in the postmenopausal woman. (C) 2018 Elsevier Masson SAS. All rights reserved.