LAUSR

The compliance of large elastic arteries in the cardiothoracic circulation declines, whereas sympathetic nervous system activity increases markedly with advancing age in adult humans. We tested the hypothesis that the reduction in compliance of the large elastic arteries with age is associated with elevations in sympathetic tone to vascular smooth muscle in 16 young and 17 older adults. Carotid arterial compliance (via ultrasonography) was 45% lower in healthy older compared with young men (P<0.001), and was inversely related to sympathetic nerve activity (via microneurography) (r=−0.51; P<0.005). Statistically correcting for sympathetic nerve activity abolished the age-related difference in arterial compliance (P=0.35). Our results suggest that increases in the sympathetic tone of vascular smooth muscle may have a mechanistic role in the age-related reduction in large artery compliance.