ETHNIC-DIFFERENCES IN HEMODYNAMIC-RESPONSES TO STRESS IN HYPERTENSIVEMEN AND WOMEN

Hemodynamic response patterns to three laboratory stressors were compa red in 63 mildly hypertensive black and white men and women. Ethnic gr oups were matched for age, body mass index, and casual blood pressures . Stressors included a mental arithmetic task, a simulated public spea king task, and a forehead cold presser test. Blood pressure increases during the stressors were similar in the two ethnic groups. However, t he presser responses were mediated by greater vascular tone in black c ompared to white subjects. These differences persisted whether the hem odynamic response pattern was associated with an overall fall (speech task) or rise (cold presser) in systemic vascular resistance. Gender d ifferences in the hemodynamic basis of presser responding were also ob served. Women, compared to men, exhibited greater increases in heart r ate and smaller vascular contributions to their blood pressure increas es during stress. Ethnic and gender differences are discussed in terms of the neurohumoral mechanisms mediating the cardiovascular stress re sponse. The findings are consistent with converging evidence suggestin g that P-adrenergic receptor down-regulation is characteristic of hype rtension in whites, whereas heightened vascular cr-receptor sensitivit y or early vascular hypertrophy may be a feature of hypertension in bl acks.