The process of healthy aging causes several changes in autonomic function that may impair a person's ability to adapt to stress. However, in the absence of disease and under usual conditions, aging has a relatively small impact on functional ability.
Autonomic changes due to aging of the cardiovascular system include reduced baroreflex sensitivity, impared beta and alpha adrenergic responses to sympathetic activation, heightened sympathetic nervous system activity, and reduced parasympathetic control of heart rate. These changes may predispose elderly people to orthostatic, postprandial, and drug-induced hypotension.
Changes in thermoregulation with aging may predispose elderly people to hypothermia and heat stroke. These changes include reduced heat generation, conservation, and dissipation, associated with reduced vasoconstriction during cold exposure and impaired vasodilatation and sweating during heat exposure.
There is a small age-related decline in innervation of the myenteric plexus of the gut and reduction in esophageal and intestinal motility. However, in the absence of disease or medications, these are rarely symptomatic.
Common symptoms of consitpation, urinary incontinence, and sexual dysfunction in old age are usually due to medications and diseases outside the autonomic nervous system.