Sex differences in healthy human heart rate variability: A meta-analysis

Area of Science:

• Physiology
• Cardiovascular Health
• Autonomic Nervous System Function

Background:

• Heart rate variability (HRV) is a key indicator of autonomic nervous system (ANS) function.
• Understanding sex differences in HRV is crucial for personalized cardiovascular health strategies.
• Previous research suggests potential sex-based variations in cardiac autonomic control.

Purpose of the Study:

• To quantitatively synthesize current evidence on sex differences in cardiac autonomic control.
• To analyze sex-specific patterns in heart rate variability (HRV) measures.
• To identify factors influencing observed sex differences in HRV.

Main Methods:

• A comprehensive meta-analysis of published studies was conducted.
• Data from 172 studies, including 63,612 participants, were analyzed.
• 1154 effect size estimates across 50 different HRV measures were aggregated.

Main Results:

• Females demonstrated significantly lower mean RR interval and standard deviation of RR intervals (SDNN).
• Female HRV showed significantly less total power, with greater high-frequency (HF) and less low-frequency (LF) power, resulting in a lower LF/HF ratio.
• Meta-regression indicated significant influences of age, respiration control, and recording length on HRV.

Conclusions:

• Despite higher mean heart rates, females exhibit greater vagal activity, as indicated by HF power.
• Sex-based differences in HRV reflect distinct autonomic control mechanisms.
• These findings underscore the importance of considering sex in the interpretation of HRV and autonomic function.