Functional changes in autonomic nervous responses with ageing.

The effects of ageing on autonomic nervous responses have been investigated in 29 young adults, 64 healthy elderly in the age range 66 to 86 years, and 20 elderly in-patients with hypothermia, instability of bladder function or marked orthostatic hypotension. In the healthy elderly group, the beat-to-beat variation in response to postural change was significantly diminished, the vasoconstrictor response to cooling reduced and baroreflex sensitivity during lower-body negative pressure was decreased compared with young adults. Patients with an atronic bladder, determined by urodynamic tests, showed an even more marked decrease in baroreflex sensitivity. The multisystem nature of these autonomic disturbances suggests that physiological impairment may occur in autonomic neural pathways with ageing.