Sex differences in heart rate responses to postural provocations

Abstract Sex differences are known in several facets of cardiac electrophysiology, mostly concerning myocardial repolarisation. In this study, heart rateand heart rate variability(HRV) responses to postural provocations were compared in 175 and 176 healthy females and males, respectively (aged 33.1 ± 9.1 years). Two different postural provocative testswith position changes supine→ sitting→standing→supine and supine→standing→ sitting→supine (15-min standing, 10-min other positions) were performed up to 4 times in each subject. Heart rateand heart rate variabilityspectral indices were measured in 5-min windows before positional changes. At supine position, females had averaged heart rateapproximately 5 beats per minute (bpm) faster than males and this sex difference was practically constant during the postural changes. In both sexes, changesupine→ sittingand supine→standing increased heart rateby approximately 10 and 30 bpm, respectively, with no statistical differences between the sex groups. At supine baseline, females had normalised high frequency components (nHF) of HRV approximately 7% larger compared to males (p