Menstrual Dysfunction, Hypoestrogenism, And Cardiac Parameters In Young Endurance Runners

Abstract

PURPOSE: Menstrual dysfunction is common among endurance runners and may impact cardiovascular responses to exercise. The objective of this study was to examine the relationships among menstrual status, circulating levels of steroid hormones, cardiovascular function, and endurance performance in a group of female endurance athletes. METHODS: College-aged (18-22 yrs) female endurance distance runners reporting a history of eumenorrhea (EAs, n=11) or menstrual dysfunction (MDAs, n=9) performed a modified Bruce Protocol Treadmill Test. Salivary estradiol, testosterone, and cortisol levels, circulating lactic acid levels, and ECG data were collected pre- and post-run. Heart rate, VO2max, time to exhaustion, and rate of perceived exhaustion were measured pre-, during, and post-run. RESULTS: Athletes reporting menstrual dysfunction had significantly lower resting estradiol levels and higher testosterone levels than EAs, although these groups did not differ in training regimen, BMI, or body fat %. MDAs had significantly lower heart rates from prolonged ST intervals before, during and after the treadmill test. There were no differences in time to exhaustion, rate of perceived effort or VO2max between groups. CONCLUSION: Lower estradiol levels link neuroendocrine reproductive dysfunction with altered cardiovascular responses to training in female endurance athletes, though do not appear to influence submaximal performance. We propose that depressed heart rate and hypoestrogenism heart rates in young female athletes could aid in the early identification of the “athlete triad” and may indicated heightened risk for future cardiovascular disease.