Introduction: Female sex hormones, estrogen and progesterone regulate various phases of the menstrual cycle. Hormonal changes tend to affect various parameters of physical fitness. Maximum oxygen uptake (VO2 max) is a measure of aerobic power. This study was planned to assess effect of different phases of menstrual cycle on cardiorespiratory parameters like pulse rate, respiratory rate and VO2 max.
Methods: 100 female medical students in the age group of 17-22 years were studied for three consecutive menstrual cycles. Weight, resting pulse rate, respiratory rate and VO2 max were measured during premenstrual phase (20th-25th day) and postmenstrual phase (5th to 10th day).
Results: It was observed that there was a significant increase in body weight, pulse rate, and respiratory rate during premenstrual phase. There was a decrease in VO2 max during the premenstrual phase.
Conclusion: This study indicates that there is decreased cardio-respiratory efficiency during premenstrual phase.
Keywords: Menstrual cycle; VO2 max; pulse rate and respiratory rate; weight.