Effects of Moderate Aerobic Exercise Combined with Caloric Restriction on Circulating Estrogens and IGF-I in Premenopausal Women

摘要

This proposal entitled Effects of moderate aerobic exercise combined with caloric restriction on circulating estrogens and IGF- 1 in premenopausal women examined the effects of exercise training combined with caloric restriction, resulting in weight loss, on two hormonal biomarkers for breast cancer i.e., circulating estrogens and insulin-like growth factor I (IGF-I). In 33 women who completed the study, exercise 4 X per wk at 79 6 % of maximal heart rate combined with an 32% decrease in caloric intake over four menstrual cycles produced significant increases in aerobic capacity (27 5%), decreases in body weight loss ranging from 1-9 kg, and loss of body fat ranging from 5 to 12% of initial percent fat. Light conditioning resulted in significant gains in aerobic capacity (30 5%), but only produced a trend toward a decrease in body fat percent (-1.2%), and only a small change in body weight (-0.8 kg). Despite the highly significant changes in body composition and body weight in the exercising group, preliminary results indicate no significant changes in serum estradiol or serum estrone. IGF-I did not change significantly either, indicating that chronic exercise and dieting do not result in favorable changes in two hormonal biomarkers for breast cancer in this age group.