Influence of age and gender on autonomic regulation of heart

Heart rate variability (HRV) is a non-invasive method to measure cardiac autonomic function. Impairments in HRV have been proposed as independent risk factor for increased cardiac mortality and morbidity. Cardio protective phenomenon in females has been hypothesized to be due to differential autonomic tone. Age related loss of vagal control has been reported as predisposing factor for the development of cardiovascular disease. In this study we assessed effect of age and gender on autonomic regulation of heart in healthy volunteers. HRV data of 189 subjects (114 males and 75 females) were analyzed in time and frequency domains using customized program. Artifact free 5 min electrocardiogram segment was used for analysis. It was ensured that none of the subject had medical illness such as diabetes, hypertension, thyroid disorders, cardiac disorders, diseases potentially related with autonomic neuropathy and major psychiatric illness by careful history and clinical examination. HRV recordings were done under standard laboratory condition. On correlation analysis SDNN, RMSSD, total power negatively correlated with age suggesting reduced autonomic regulation of heart with increase in age (SDNN: r = −0.444, p