Bock JM, et al. - Among 14 young (25±4yrs) and 15 older (68±4yrs) participants, sympathoexcitatory stimuli-induced alterations in central-artery stiffness and wave reflection were studied. The participants were asked to complete 3 minutes of the cold pressor test (CPT) and lower-body negative pressure (LBNP) separated by 15 minutes. Young vs older subjects had larger changes in mean arterial pressure (MAP, 18±7 vs 9±5mmHg), carotid-femoral pulse wave velocity (1.3±0.7 vs 0.6±0.9m·sec-1), central augmentation pressure (4±2 vs 6±3mmHg), and augmentation index (18±9 vs 7±4%). Direct modulation of central hemodynamics by the sympathetic nervous system was suggested. Differential blood pressure responses were largely responsible for age-related differences in central artery responsiveness to sympathoexcitatory stimuli.