Adrenal-medullary and adrenal-cortical responses to understimulation and overstimulation: comparison between type A and type B persons.

Male and female university students, classified as Type A and Type B persons with the aid of a questionnaire measuring coronary-prone behavior, were studied while doing mental work under laboratory conditions, characterized by understimulation and overstimulation, and while unoccupied (baseline session). The urinary excretion of adrenaline, noradrenaline and cortisol, heart rate (in the understimulation and baseline conditions) and self-reports were used as indices of arousal. The overall picture showed that both experimental conditions increased arousal, the rise being particularly pronounced for cortisol excretion during understimulation and for adrenaline excretion during overstimulation. Comparison between groups showed that cortisol excretion was higher in Type A than in Type B persons of both sexes during understimulation. Adrenaline excretion was about the same in both sexes (Type A and Type B) during understimulation, but was higher in males than in females during overstimulation. There were no group differences in performance.