Plasma clearance of noradrenaline does not change with age in normal subjects.

Noradrenaline kinetics (plasma concentrations, plasma clearance and appearance rates) were investigated in seven elderly healthy subjects and in six young healthy subjects. Forearm venous plasma noradrenaline concentrations were higher in the elderly subjects compared with the young subjects. Plasma clearance of noradrenaline was identical in the two groups. The increase in plasma noradrenaline concentration, with age, probably reflects an increased sympathetic nervous activity.