Submitted on November 22, 2005
Accepted on May 9, 2006
Preserved Autonomic Function in Amenorrheic Athletes
Megan M Wenner1, Allen V Prettyman2, Raelene E Maser3, and William B. Farquhar1*
1 Department of Health, Nutrition, and Exercise Sciences, University of Delaware, Newark, Delaware, United States
2 School of Nursing, University of Delaware, Newark, Delaware, United States
3 Department of Medical Technology, University of Delaware, Newark, Delaware, United States
* To whom correspondence should be addressed. E-mail: wbf{at}udel.edu.
Reproductive hormones such as estradiol and progesterone are known to influence autonomic cardiovascular regulation. The purpose of this study was to determine if amenorrheic athletes (AA) have impaired autonomic cardiovascular regulation compared to eumenorrheic athletes (EA). Thirty-five athletes were tested: 13 AA (19±1 yrs), 13 EA (21±1 yrs), and 9 EA (23±1) on oral contraceptives (EA-OC). Multiple indices of autonomic cardiovascular regulation were assessed: respiratory sinus arrhythmia (RSA), cardiovagal baroreflex sensitivity (BRS) via phase IV and phase II of the Valsalva maneuver, a spontaneous index of BRS, and the heart rate and blood pressure responses to orthostatic stress (20 minute 60 degree head-up tilt). RSA was not different among the groups. There were no group differences in the spontaneous index of BRS (AA=30±6, EA=24±3, EA-OC=29±5 msec/mmHg) or in phase II (AA=8±2, EA=7±1, EA-OC=8±1 msec/mmHg) of the Valsalva. There was a difference in BRS during phase IV (AA=21±3, EA=15±1, EA-OC=26±6 msec/mmHg; ANOVA p=0.04). Tukey's post hoc test indicated that BRS was greater in the EA-OC group compared to the EA group (p=0.04). There were no differences in cardiovascular responses to orthostatic stress among the groups. In conclusion, AA do not display signs of impaired autonomic function and orthostatic responses compared to EA or EA-OC during the follicular phase of the menstrual cycle.
