Stress and age effects on catecholamines in normal subjects

Abstract

In the first study, plasma and urinary catecholamine levels were studied in healthy young volunteers following exposure to a thermal test (cold-pressor test). Plasma noradrenaline was markedly elevated for some time after the stress ceased. In a second study, a cognitive-conflict task (Stroop's coloured-word conflict test) was used as the stress for groups of young and old, male and female volunteer subjects. There were group differences in the catecholamine responses: all groups except the young females responded with considerable increases in urinary adrenaline excretion. Noradrenaline, however, was raised only in the two elderly groups. All the subjects were considerably aroused by the test as judged by changes in the skin conductance, heart rate and electrocardiogram. The significance of decreased responsivity of the sympatho-adrenomedullary system to stressful situations in young women is discussed with reference to their low incidence of coronary artery disease.