Hemodynamic abnormalities in borderline hypertension during mental stress.

Cardiovascular reactivity to mental stress was studied in 41 male borderline hypertensives in comparison with 37 male normotensives of the same age. In addition to a higher near-basal blood pressure, the borderline hypertensive group showed stronger absolute and percentage increases of systolic and diastolic blood pressure during stress. The increases of heart rate and cardiac output and the decreases of total peripheral resistance were also greater in borderline hypertensives. Stroke volume showed a slight increase only in this group. The reaction of mean arterial pressure correlated in both groups with the increase of cardiac output. The relationship between the reactions of cardiac output and total peripheral resistance was high both in normotensives and borderline hypertensives, and the regression line in normotensives was shifted to the right in borderline hypertensives. The results indicate an increased integrated change of circulatory parameters during mental stress in borderline hypertension, with a dominantly stronger cardiac reaction. They underline the significance of an autonomic imbalance for the pathogenesis of borderline hypertension.