[Changes in beta-adrenergic regulation of the cardiovascular system during aging].

Changes in beta-adrenergic regulation of the cardiovascular system in aging involved 40 healthy subjects aged 20-34, 60-74 and 75-89 have been studied. Single drug loads with propranolol (0.6 mg/kg, per os) and isadrin (10 mg, sublingually) were used. With aging, the beta-adrenergic regulation of heart at various levels (in the central and autonomic vegetative nervous system, the ACTH-cortisol system) changes. The negative effect of beta-adrenergic blockade on the cardiovascular system enhances, that is a result of a more significant suppression of the sympathetic effects on the heart and peculiarities of the propranolol pharmacokinetics in old age. The reactivity of beta-adrenergic mechanisms in response to their stimulation decreases as well. Blockade of the beta-adrenoreceptors produces a distinct saving effect on the performance of the cardio-respiratory system under conditions of physical loading, that is due to a suppression of sympathetic hyperactivity and elimination of excess strain in the ACTH-cortisol system at the peak submaximal physical loading.