Interactive influences of ethnicity, gender and parental hypertension on hemodynamic responses to behavioral challenge.

To determine the independent and interactive influences of ethnicity, gender and parental hypertension on the magnitude and patterning of hemodynamic responses to standardized laboratory stressors, 112 normotensive, young adult African-American and Caucasian subjects (56 women, 56 men) completed a four-task protocol: three psychological stressors (the Stroop Color Word task, mental arithmetic and mirror tracing) and the forehead cold pressor test. Blood pressure (BP), heart rate (HR) and impedance derived measures of cardiac pre-ejection period and stroke volume were measured at rest and during each task; calculated indices of cardiac output and total peripheral resistance were also computed. Women responded to the psychological stressors with significantly larger increases in HR and cardiac output, less change in total peripheral resistance and greater attenuation of cardiac pre-ejection period than did men; however, blood pressure responses did not vary by gender, ethnicity or parental history of hypertension. Across tasks, African Americans showed larger elevations in total peripheral resistance than did Caucasians; conversely Caucasian subjects showed a more pronounced cardiac responsivity to stress, as evidenced by an elevated cardiac output and concomitant decrease in cardiac pre-ejection period, compared to their African-American counterparts. The ethnic differences in reactivity to psychological stressors were more apparent among males, while the gender differences were generally more pronounced among African Americans. Finally, the cold pressor test elicited larger increases in systolic blood pressure (SBP) among Caucasian subjects with family history positive (FH+), relative to family history negative (FH-) subjects, and also caused a greater reduction in HR among males compared to females.