Classification of individual differences in cardiovascular responsivity: The contribution of reactor type controlling for race and gender

Classification of 150 normotensive or mildly hypertensive men and women int o myocardial, vascular, or mild reactors was accomplished using a regressio n-based approach. The method was based on the participants' cardiac output (CO) and total peripheral resistance (TPR) reactivity to the speech, presen tation task. This task purportedly can elicit both myocardial and vascular responses. Cut-scores were based on the y-intercept from the linear regress ion of the CO reactivity on TPR reactivity and vice versa. A greater percen tage of Black men were classified as vascular responders as compared to Bla ck women and White participants. Groups were found to differ on cardiovascu lar reactivity to the speech preparation, cold presser, and mirror tracing tasks in predictable ways, after controlling for gender and ethnicity. Grou ps were also differentiated by ambulatory blood pressure and hypertensive s tatus. The study supports the classification of homogeneous groups of parti cipants based on the relative extent to which myocardial or vascular mechan isms dominate the reactivity to stress.