Women In Steady Exercise Research (WISER) Sister

OBJECTIVES:

Primary

• To conduct a dose response study of low- or high-dose exercise over 5 menstrual cycles, with no concomitant dietary changes producing a caloric deficit, in healthy younger women with ≥ 18% lifetime risk for developing breast cancer.
• To determine the effects of this exercise regimen on variables known to be associated with breast mitotic activity in these participants.

Secondary

• To assess changes in other physiologic parameters associated with breast mitotic activity (i.e., urinary progesterone [pregnanediol-glucuronide, PdG] from daily first morning urine samples; follicular phase circulating [serum] levels of estradiol, progesterone, testosterone, and prolactin; follicular phase breast density [fibroglandular tissue volume] from magnetic resonance imaging; estrogen metabolites [estrone, estradiol, estriol, 2-OHE_1, 2-OHE_2, 4-OHE_1, 4-OHE_2, 16-OHE_1 and ratios]; adipokines [i.e., adiponectin and Leptin]; and body composition [i.e., % body fat, lean mass, fat mass, total mass]) in these participants.
• To assess the extent to which changes in body composition and/or body mass mediate observed changes in these participants.
• To quantify the relationship between estrogen and progesterone from daily urinary measurements with observed menstrual cycle alterations such as follicular and luteal phase length changes, and ovulatory status in these participants.
• To compare levels and exercise-induced changes in urinary estrogens, estrogen metabolites, circulating hormones, adipokines, and body size across two groups of women who differ as to breast cancer risk in an exploratory manner.