title: Effect of Different Phases of Menstrual Cycle on Heart Rate Variability (HRV).
abstract: BACKGROUND
  Heart Rate Variability (HRV), which is a measure of the cardiac autonomic tone, displays physiological changes throughout the menstrual cycle. The functions of the ANS in various phases of the menstrual cycle were examined in some studies.
  
  
  OBJECTIVE
  The aim of our study was to observe the effect of menstrual cycle on cardiac autonomic function parameters in healthy females.
  
  
  METHODS
  A cross-sectional (observational) study was conducted on 50 healthy females, in the age group of 18-25 years. Heart Rate Variability (HRV) was recorded by Physio Pac (PC-2004). The data consisted of Time Domain Analysis and Frequency Domain Analysis in menstrual, proliferative and secretory phase of menstrual cycle. Data collected was analysed statistically using student's pair t-test.
  
  
  RESULTS
  The difference in mean heart rate, LF power%, LFnu and HFnu in menstrual and proliferative phase was found to be statistically significant. The difference in mean RR, Mean HR, RMSSD (the square root of the mean of the squares of the successive differences between adjacent NNs.), NN50 (the number of pairs of successive NNs that differ by more than 50 ms), pNN50 (the proportion of NN50 divided by total number of NNs.), VLF (very low frequency) power, LF (low frequency) power, LF power%, HF power %, LF/HF ratio, LFnu and HFnu was found to be statistically significant in proliferative and secretory phase. The difference in Mean RR, Mean HR, LFnu and HFnu was found to be statistically significant in secretory and menstrual phases.
  
  
  CONCLUSIONS
  From the study it can be concluded that sympathetic nervous activity in secretory phase is greater than in the proliferative phase, whereas parasympathetic nervous activity is predominant in proliferative phase.
authors.affiliation: Resident, Department of Physiology, Government Medical College , Patiala, Punjab, India .
authors.forename: Tejinder Kaur
authors.initials: TK
authors.lastname: Brar
authors.affiliation: Professor and Head of Department, Department of Physiology, Government Medical College , Patiala, Punjab, India .
authors.forename: K D
authors.initials: KD
authors.lastname: Singh
authors.affiliation: Professor, Department of Physiology, Government Medical College , Patiala, Punjab, India .
authors.forename: Avnish
authors.initials: A
authors.lastname: Kumar
keywords: Autonomic nervous system; Heart rate; Low frequency; Menstrual cycle; Vagal activity