Comparison of Heart Rate Variability Between Sexes: Impact of a Physically Active Lifestyle

Sex differences and lifestyle factors such as physical activity play an important role in cardiovascular autonomic regulation. Heart rate variability (HRV) is a widely used marker of cardiac autonomic modulation and cardiovascular health. However, the combined influence of sex and physical activity levels on HRV in young, healthy adults has not been sufficiently explored. Therefore, this study investigated the effects of sex and a physically active lifestyle on HRV in men and women. A cross-sectional study was conducted on a cohort of young, healthy adults aged 18–30 and categorized into four groups based on: physically active men (AM; n = 37), sedentary men (SM; n = 44), and physically active women (AW; n = 31) and sedentary women (SW; n = 40). Regarding the impact of lifestyle, the AM group exhibited 41% higher total variance (VAR-RR) and 34% higher RMSSD (a parasympathetic index) than the SM group. The AW exhibited 74% and 78% higher VAR-RR and RMSSD, respectively, compared to the SW. Furthermore, the physically active groups (AM and AW) displayed a 75% and 50% lower LF/HF ratio, respectively, compared to their sedentary counterparts. Interestingly, the LF/HF ratio was 66% higher, and the RMSSD was 20% lower in the AM group than in the AW group. HRV indices demonstrated large to very large effect sizes. In conclusion, these findings demonstrate significantly advantage in cardiac autonomic modulation among physically active individuals and women. Together, these results reinforce the roles of female sex and an active lifestyle as important protective factors for cardiovascular health.