Cardiovascular responses of boys exhibiting the type A behavior pattern.

Two experiments measured the cardiovascular responses of fourth- and fifth- grade boys to tasks that were relevant to Type A characteristics. Boys were classified as Type A or Type B by the Adolescent Structured Interview (ASI) and Matthews Youth Test for Health (MYTH). Results showed that ASI and MYTH assessments were significantly and moderately correlated--a finding similar to the association among Type A measures in adulthood. During the competition induced by Experiment 1 tasks, ASI Type As showed greater elevations in heart rate than did Type Bs. During the second game of this experiment, the more extreme the Type A behavior, the greater the elevation in systolic and diastolic blood pressure. In contrast, MYTH Type As exhibited enhanced systolic blood pressure in response to the difficult, frustrating, and slow-paced tasks presented in Experiment 2. They also increased in heart rate with increasing exposure to the tasks. These results resemble the findings from the adult Type A psychophysiologic studies and suggest that the cardiovascular responses associated with the Type A pattern may begin in childhood.