Cardiovascular autonomic nervous response to postural change in 610 healthy Japanese subjects in relation to age.

To determine the effect of aging on the cardiovascular response to postural change, we examined the cardiovascular sympathetic and parasympathetic response to active standing in 610 healthy Japanese subject (6-83 years) measuring the initial heart rate (HR) response for 3 min in the supine and standing position, we also measured the coefficient of variation of R-R interval (CV(R-R)). As a result, the cardiovascular response to active standing demonstrated a different change with aging between sympathetic and parasympathetic. Sympathetic function was in a sthenia state in young subjects, and that this function declined with age increasing. Whereas, parasympathetic function was immature enough to inhibit the sympathetic tone in young subjects and matured at 20 years of age, and had an ability to inhibit sympathetic tone. CV(R-R) show a linear change that decline with age increasing. These results indicated that the cardiovascular parasympathetic response to active standing shows a characteristic change with aging that differs from cardiovascular parasympathetic at rest represented by CV(R-R). The present study is the first report to demonstrate the cardiovascular response to standing in relation to aging in large population. These results suggested that the cardiovascular response to postural change is dependent on subject's age.