Determinants of heart rate variability in the general population: The Lifelines Cohort Study

Heart rate variability (HRV) is an important marker of heart health, with low values reflecting reduced vagal control of the heart rhythm.The purpose of this study was to investigate the extent to which a broad range of demographic (age, sex), lifestyle (physical activity, smoking, alcohol use), and psychosocial factors (stress, social well-being, neuroticism) explain individual differences in HRV in the general population.Using baseline data of 10-second electrocardiograms from the Lifelines Cohort Study (n = 149,205; 58.7% female; mean age ± SD: 44.6 ± 13.2 years), we calculated the root mean square of successive differences (RMSSD) between adjacent interbeat intervals as an index of cardiac parasympathetic nervous system activity. We also calculated RMSSD adjusted for its dependency on heart rate (cRMSSD). The association of demographic, lifestyle, and psychosocial factors with RMSSD was assessed using hierarchical linear regression models adjusting for potential confounding effects of medication use, disease, and body mass index.HRV strongly declined with age and was consistently higher in women. These demographic factors together explained 17.4% of the variance in RMSSD and 21.9% in cRMSSD. Physical activity, alcohol use, and smoking showed some significant associations with RMSSD, but stress, social well-being, and neuroticism did not. Adding lifestyle and psychosocial factors to the model additionally explained <0.50% of the variance.Age and sex were the most important determinants in this very large general population cohort, explaining almost one-fifth of the individual differences in HRV. The additional contribution of lifestyle and psychosocial factors was negligible.