The effect of age and gender on heart rate variability in healthy individuals

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Objective Cardiovascular autonomic function, represented by heart rate variability (HRV) is a simple, non-invasive measure used to determine alteration of sympathetic and parasympathetic control. The aim of the present study was firstly to evaluate the effect of age and gender on HRV measures, and secondly to determine the relationship between measures of HRV and functional capacity in healthy individuals Methods This was a retrospective, single centre, cross-sectional, observational study. Data were collected between January 2018 and July 2019. Sixty-eight healthy participants (age range: 19-78 years) were stratified according to age into the younger age group (<40 years of age, N = 43, males, N = 26; females, N = 17) or the older age group (>55 years of age, N = 25, males, N = 14; females, N = 11). Frequency domain HRV measures (i.e. absolute and normalised low frequency power (LF), high frequency power HF and their ration i.e. LF/HF ratio) were derived from RR interval and recorded at rest (supine position) for 30 minutes. Simultaneous non-invasive gas-exchange and central haemodynamic measurements (bioimpedance) were collected at rest and during maximal graded cardiopulmonary exercise stress test using semi-recumbent cycle ergometer. Results The mean age of the younger group was 26 ± 6 years and older 64 ± 6 years. Cardiorespiratory fitness (i.e. peak oxygen consumption) was significantly reduced in older compared to younger age group (1.60 ± 0.57 vs. 2.38 ± 0.74 L/min, p < 0.01). The mean absolute values of HF power declined with age in males by 32% (younger, 1156 ± 806 ms2 vs. older, 835 ± 488 ms2, p = 0.18), but not in females 3% difference (younger, 1182 ± 958 ms2 vs older, 1150 ± 843 ms2, p= 0.92). There was no significant difference in HF power between males and females in the younger age group (young male, 1156 ± 806 ms2 vs. young female, 1182 ± 958ms2, p = 0.92), but older males demonstrated 32% lower HF power than older females (835 ± 488 ms2 vs. 1150 ± 843 ms2, p= 0.25). Further analyses revealed no significant relationship between measures of heart rate variability and functional capacity i.e. the HF power was not significantly related to peak oxygen consumption in males (r= - 0.15, p= 0.36) or females (r= 0.05, p = 0.80). Conclusions High frequency power of the heart rate variability declines with age more in men but not women. Gender difference in high frequency power is apparent in older but not younger age, with older women showing nearly one third higher HF than older men. Measures of heart rate variability do not predict cardiorespiratory fitness