Unique problems in the treatment of the older hypertensive male. Introduction: increased sympathetic nervous system activity in the elderly

Sympathetic activation increases blood pressure via effects on the heart, blood vessels and the kidney, and influences micturition and prostatic function via effects on the urinary sphincter and prostate muscular stroma. A systematic increase in sympathetic activity in older subjects would be expected to cause or exacerbate both hypertension and prostatism. Although assessment of sympathetic nervous system activity in humans is difficult, available evidence accumulated over the last decade strongly suggests that ageing is associated with increased sympathetic nervous system activity. There is general agreement that plasma norepinephrine levels are elevated in old, as compared with young, healthy human subjects. Furthermore, the rate of entry of norepinephrine into the circulation, a measure of sympathetic activity, is increased in older subjects. Plasma norepinephrine responses to both cardiovascular and metabolic stimuli are also accentuated in the aged so that the rise in plasma norepinephrine with upright posture and in response to oral glucose ingestion is greater in old than in young human subjects. As the clinical usefulness of selective alpha 1-adrenergic inhibitors is theoretically greater in states accompanied by increased sympathetic activity, the idea that selective alpha 1-adrenergic inhibition might be particularly useful in treating simultaneous hypertension and prostatism in older men has a sound physiological rationale.