The purpose of this study was to evaluate the function of cardiac autonomic nervous activity and post-exercise vagal reaction during the menstrual cycle. The subjects were healthy young women (n=13, age 19.9±0.6 years) with normal menstrual cycles. Power spectral analysis of heart rate variability was used to examine cardiac autonomic nervous activity. In addition, the time con stant of heart rate decline for the first 30 sec (T₃₀) after exercise was used to examine post-exercise vagal reactivation.
Results show that the cardiac autonomic nervous activity changes during the menstrual cycle. Also, T₃₀ shows significant change during the menstrual cycle, especially T₃₀ retardation in the early luteal phase. These results suggest that an imbalance of estradiol and progesterone hormones may be responsible for these changes in cardiac autonomic nervous activity during the menstrual cycle.

[Objective] The aim of this investigation was to evaluate serum steroid hormone responses to acute resistance exercise. [Methods] Subjects were young healthy males (n=6) and females (n=6) . Each group performed three sets of 10 leg press and 10 bench press exercises at an intensity of their individual 10-repetition maximum (1ORM), with 1 min rest between sets. Blood samples were collected before (Pre-Ex) and immediately following the exercise (P0), 30 mm (P30), 60 mm (P60), and 24 hours (P24h) after the exercise. Levels of blood lactate, serum testosterone, dehydroepian drosterone sulfate (DHEAS) and cortisol were determined. [Results] The levels of blood lactate in males and females significantly increased at P0 and P30 compared with Pre-Ex (p<0.05) . In males, the serum level of testosterone significantly increased at PO (p<0.05), whereas in females, it significantly decreased at P0, P30, P60, P 24 h. (p<0.05) . The level of DHEAS significantly increased at P0 in both males and females (p<0.05) . [Conclusion] The change in the level of testosterone was different between males and females, but that of DHEAS showed a similar pattern for both sexes. The data suggest that DHEAS could be a useful indicator for evaluating the anabolic status of acute resistance exercise in females.

[Objective] The aim of this investigation was to evaluate salivary dehydroepiandrosterone (DHEA) responses during a competitive period among female football players.
[Methods] Subjects were college female football players (n=9) . Saliva and blood samples were collected at 18 : 00 (6 : 00 pm) and the profile of mood state (POMS) was recorded during a period of normal training (Pre), 3 days of competition (Competition), and a recovery period (Post) . Levels of salivary DHEA, cortisol, and serum creatin kinase (CK), urea nitorogen (UN), were determined.
[Results] The levels of salivary DHEA significantly increased during competition (2 nd days) compared with Pre (p<0.05), and significantly decreased after competition compared with Pre (p<0.05) . The levels of salivary cortisol significantly increased during the competition (2 nd and 3 rd days) compared with Pre (p<0.05) . Whereas it decreased after competition compared with Pre. The levels of serum CK significantly increased during the competition (2 nd days) compared with Pre (p<0.05) . The levels of serum UN did not change during the study. The fatigue score of POMS significantly increased during competition (2 nd days) compared with Pre (p<0.05) .
[Conclusion] These data suggest that DHEA could be a useful endocrinological indicator for evaluating training status in female athletes.