Effect of Harassment and Competition Upon Cardiovascular and Plasma Catecholamine Responses in Type A and Type B Individuals

ABSTRACT Two experiments examined the relationship between Type A behavior and cardiovascular and plasma catecholamine responses to experimental competition and harassment. Experiment I showed that, in 44 male adults, the presence of a hostile opponent caused no significant differences in the responses of Type B's. In A's, by contrast, hostility elicited greater increases in systolic blood pressure, heart rate and plasma epinephrine during competition. Behavior pattern A appears selectively predisposed to enhanced reaction to hostile interactions, but competition alone does not distinguish between individuals with A and B behavior patterns. Experiment II, with 20 cases, was carried out to determine whether or not the absence of A‐B differences in the presence of a nonhostile competitor could be explained by Type B's reactivity to the challenge of competition alone. The results were consistent with this interpretation. A's showed greater blood pressure and plasma epinephrine evaluations than B's when both types were confronted by the challenge of task performance. Consideration was given to the role of sympathetic activation in mediating the tendency of Type A individuals to develop coronary heart disease.