Autonomic control of cardiac chronotropic function in man as a function of age: assessment by power spectral analysis of heart rate variability.

The analysis of age-related features of the autonomic heart rate control during various periods of postnatal human ontogenesis is presented. The study was performed in 354 apparently healthy individuals of either sex, ranging in age from 3 months to 89 years. The method of spectral analysis of heart rate variability was used. We demonstrated different ratios between the sympathetic and the parasympathetic influences upon heart rate control in relation to age. In infancy and after 50 years, there is a prevalence of the sympathetic activity against a background of weak parasympathetic activity. In early years, the prevalence of the parasympathetic activity is observed at a sufficiently high sympathetic activity level.