Abstract：The purpose of this study was to examine the influence of weight training on blood pressure and autonomic nervous balance in women during the normal menstrual cycles. Twenty-one normally menstruating women were recruited for this study. Participants were assigned into weight training group and sedentary group in a random order. Heart rate variability and blood pressure were monitored at rest for every 7 days after menstrual bleeding for 2 complete menstrual cycles. Participants were performed eight different types of resistance weight trainings twice a week for 4 weeks (12 repetitions per set, 3 sets, 70% maximum strength). The results showed that parasympathetic nervous activity was significantly decreased in the first week after menstrual bleeding. Systolic blood pressure tended to be lower during the luteal period for the both groups. Changes in diastolic and systolic blood pressures were less pronounced for the weight training group as compared to the control group. This study concludes that the blood pressure and heart rate variability were influenced by the menstrual cycle hormones, whereas the weight training could improve the stabilization of blood pressure. It took a longer recovery time for weight training before and after the menstrual bleeding. The result of the study suggests a hemodynamic benefit of weight training for young women in regulating the blood pressure. (Full text)