title: Effect of female sex hormones on cardiorespiratory parameters.
abstract: BACKGROUND
  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 (VO2max) 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 VO2max.
  
  
  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 VO2max were measured during premenstrual phase (20th-25thday) and postmenstrual phase (5thto 10thday).
  
  
  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 VO2max during the premenstrual phase.
  
  
  CONCLUSIONS
  This study indicates that there is decreased cardio-respiratory efficiency during premenstrual phase.
authors.affiliation: Department of Physiology, Bharati Vidyapeeth Medical College, Pune, Maharashtra, India.
authors.forename: Gayatri
authors.initials: G
authors.lastname: Godbole
authors.affiliation: Department of Physiology, Bharati Vidyapeeth Medical College, Pune, Maharashtra, India.
authors.forename: A R
authors.initials: AR
authors.lastname: Joshi
authors.affiliation: Department of Physiology, Bharati Vidyapeeth Medical College, Pune, Maharashtra, India.
authors.forename: Savita M
authors.initials: SM
authors.lastname: Vaidya
keywords: Menstrual cycle; VO2 max; pulse rate and respiratory rate; weight