Myocardial and vascular responses to challenge: A comparison of hypertensive and normotensive individuals

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Doctor of Philosophy (Ph.D.)




The purpose of this study was to examine differences between hypertensives and normotensives at baseline and in cardiovascular responses to three stressors (mirror tracing, cold pressor, and evaluated speech) and to determine if responder type groups (i.e., myocardial and vascular responders, and low reactors) within blood pressure status groups responded differently to these stressors. Healthy, unmedicated, mild hypertensives (n = 29) and normotensives (n = 29), Blacks and Whites, men and women, 25-54 years of age, served as subjects and were matched on the basis of age, sex, race, height, and weight. Using regression-derived cut scores, subjects were classified into 3 responder types (i.e., myocardial and vascular responders, and low reactors) based on their cardiac output and total peripheral resistance (TPR) responses to the presentation phase of the speech task. The proportion of hypertensives was comparable across responder types $(p > .05)$.At baseline, hypertensives had significantly greater TPR $(p < .01)$ than normotensives, whereas normotensives had significantly greater Heather Index than hypertensives $(p < .01)$. After adjusting for baseline, main effects for blood pressure status revealed that hypertensives had a significantly greater increase in blood pressure than normotensives during evaluated speech and mirror tracing as well as for TPR during mirror tracing (all p's $<$.05).Among vascular responders, hypertensives were more reactive in blood pressure than normotensives to the speech and mirror tracing tasks. Among myocardial responders, normotensives were more reactive than hypertensives in myocardial responses to mirror tracing and cold pressor. There were no blood pressure status differences for low responders.In conclusion, several differences between hypertensives and normotensives, not apparent in the overall comparisons, were evident once subjects were classified into responder types. Therefore, classifying hypertensive and normotensive subjects into responder types may be useful in determining differences between these groups that are not apparent in the overall comparisons.


Biology, Animal Physiology; Psychology, Clinical; Psychology, Physiological

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