Changes of the autonomic nervous system with increasing age

The autonomic nervous system is responsible for regulating physiological homeostasis, and comprises the sympathetic and parasympathetic nervous systems, which control ergotropic and trophotropic adaptation activities. Transmission from the preganglionic to the postganglionic neuron is effected at a nicotinic synapsis by the transmitter acetylcholine. The postganlionic sympathetic synapsis uses noradrenaline as transmitter. Plasma noradrenaline concentration increases with age, probably due to increased secretion and diminished clearance. Central nervous control is likely but not yet proven. At the receptor level of the sympathetic nervous system, a decrease in receptor affinity with down-regulation, and changes in signal transduction are observed. In contrast to the increase in sympathetic activity, the activity of the parasympathetic nervous system decreases in the elderly. At least in the heart, reduced acetylcholine release is considered certain, and the likely reason for the diminished effectiveness of parasympatholytic drugs. The earlier assumption of an increase in catecholamine release in old age has been proved wrong. All these physiological changes result in a reduction in the adaptability of the organism over time. Awareness by the anaesthesiologist of the reduced cardiovascular reserves of the elderly patient is of particular clinical relevance.