HEART RATE VARIABILITY AND CARDIOMETABOLIC PHENOTYPES IN APPARENTLY HEALTHY ADULTS: INSIGHTS INTO EARLY AUTONOMIC DYSREGULATION

Abstract

Alterations in cardiac autonomic regulation may accompany early cardiometabolic dysfunction before clinically overt disease develops. This study evaluated heart rate variability (HRV) in relation to cardiometabolic phenotypes among apparently healthy adults. A cross-sectional analytical study was conducted among 138 adults aged 18–60 years. Short term HRV was assessed using a standardized five-minute resting recording, with standard deviation of normal-to normal intervals (SDNN) and root mean square of successive differences (RMSSD) as principal indices. Anthropometric measurements, blood pressure, fasting glucose, and lipid profile were evaluated, and participants were categorized according to cumulative cardiometabolic risk-factor burden. Mean age was 36.23 ± 9.24 years, and 55.1% of participants were male. Mean SDNN and RMSSD were 52.43 ± 9.86 ms and 42.61 ± 9.99 ms, respectively. SDNN showed inverse correlations with age (r = −0.554), body mass index (r = −0.344), and fasting glucose (r = −0.282). RMSSD was inversely associated with body mass index (r = −0.400), age (r = −0.389), triglycerides (r = −0.295), and fasting glucose (r = −0.262). Lower HRV was generally observed with increasing cardiometabolic risk burden. These findings indicate that unfavorable cardiometabolic phenotypes are accompanied by measurable alterations in cardiac autonomic regulation even among apparently healthy adults. HRV may therefore provide a useful physiological phenotype for investigating early autonomic involvement in cardiometabolic dysfunction.