Age-related changes in autonomic function: relationship with postural hypotension.

Eleven elderly subjects, six with signs and symptoms of postural hypotension, were investigated for autonomic neuropathy of their cardiovascular and pupillary systems. The results were compared with those from a group of nine young subjects to define the reductions in autonomic activity that normally occur with age. There was evidence of a decline in autonomic function in the elderly, but this was no greater in the group with postural hypotension. A positive correlation was found between the level of the supine systolic pressure and the degree of postural drop. It is suggested that pathology in the vasculature and not in the sympathetic innervation is responsible for postural hypotension in the elderly.