Aging is associated with structural and functional changes in the autonomic nervous system (ANS), which innervates the whole body, and its altered function may influence almost all body systems. Changes related to aging are found in autonomic nerves and ganglia, and ANS controlled functions including cardiovascular functions. Much of the current knowledge about age-related changes in sympathetic nervous function is derived from studies of circulating catecholamine levels, norepinephrine kinetics and microneurographic recordings from sympathetic nerves of skeletal muscle. Significant evidence suggests that basal plasma noradrenaline levels increase with age. These data indicates that healthy aging is associated with elevated basal sympathetic nervous activity. In contrast, the reactivity of the sympathetic and the parasympathetic nervous activity are reduced with aging.