title: Changes of respiratory sinus arrhythmia during the menstrual cycle depend on average heart rate.
abstract: To evaluate the complex time course of changes in respiratory sinus arrhythmia (RSA) during the menstrual cycle, daily beat-to-beat morning recordings of heart rate (HR) were carried out in 26 healthy female subjects (age 20-29 years) during two menstrual cycles. For determination of fast, vagally mediated variations of HR we used a robust time-domain measure of RSA (logRSA). We found pronounced changes in HR during the menstrual cycle with a minimum in the early follicular phase and a maximum in the late luteal phase. There were large differences between individuals in the fluctuations of logRSA during the menstrual cycle that were related to average HR: subjects with a low HR exhibited higher values of logRSA in the luteal compared to the follicular phase, whereas the trend was reversed in subjects with a high HR. The difference of extreme points of logRSA fluctuations (early follicular and mid luteal phase) was correlated to average HR (r=-0.64, P < 0.001). We conclude that different patterns of RSA fluctuations occur depending on the level of average HR.
authors.affiliation: Adaptational Physiology Laboratory, Department of Physiology, University of Graz, 8010 Graz, Austria.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Seebauer
authors.forename: Matthias
authors.initials: M
authors.lastname: Frühwirth
authors.forename: Maximilian
authors.initials: M
authors.lastname: Moser
mesh_terms: D000328:Adult; D001146:Arrhythmia, Sinus / Q000503:physiopathology*; D005260:Female; D005498:Follicular Phase / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008183:Luteal Phase / Q000502:physiology; D008597:Menstrual Cycle / Q000502:physiology*; D015656:Respiratory Mechanics