Effects of the route of estrogen administration and exercise on hormonal levels in postmenopausal women

Objective: To examine the effects of exercise on serum estrogens, growth hormone, insulin, cortisol, lactate, and glucose levels in postmenopausal women receiving two routes of administration of estrogen replacement therapy (ERT).Design: Prospective, randomized, crossover study.Setting: The general clinical research center of an academic medical center.Patient(s): Eleven active, postmenopausal women.Intervention(s): The patients were screened with exercise stress testing, then oral micronized estradiol or transdermal estradiol was administered, followed by two 45-minute submaximal exercise tests. Dietary intake before the tests was standardized.Main Outcome Measure(s): The study measured maximal heart rate and aerobic power (V˙o2max), and serum levels of estradiol (E2), estrone (E1), cortisol, growth hormone (GH), insulin, glucose, and lactate.Result(s): Growth hormone, cortisol, and insulin all changed significantly in response to the 45-minute exercise bouts, but no differences were observed between the oral micronized estradiol and transdermal estradiol responses. E2 levels increased significantly during the transdermal estradiol 45-minute exercise bout; this change did not occur during the oral estradiol exercise bout. In the transdermal estradiol treatment group, the E2 levels at +30 and +45 minutes of exercise were elevated compared to the post-exercise levels at −15, 0, and 30 minutes. E1 was not significantly changed during the 45-minute exercise bouts in either group.Conclusion(s): During exercise, serum E2 levels rise significantly higher with transdermal but not oral routes of E2 administration. However, the elevated levels are not prolonged and normalize by 30 minutes after exercise. [Copyright &y& Elsevier]