CARDIOVASCULAR REACTIVITY, CORONARY RISK-FACTORS, AND SYMPATHETIC ACTIVITY IN YOUNG MEN

We have previously demonstrated that awareness of high blood pressure may increase blood pressure, plasma catecholamine levels, and stress r esponses. In the present study, three groups of 19-year-old men, all u naware of their blood pressure status, were selected from the first (g roup-1, 62+/-2 mm Hg, [mean+/-SEM], n=15), 50th (group-50, 90+/-4 mm H g, n=15), and 99th (group-99, 123+/-5 mm Hg, n=14) percentiles in casu al mean blood pressure at a screening. They were studied (blinded exam iners) with intra-arterial blood pressure recordings and multiple meas urements of arterial plasma epinephrine and norepinephrine during a me ntal arithmetic challenge and cold presser test. Despite high mean blo od pressure at the screening, group-99 did not differ from group-50 ei ther in intra-arterial mean blood pressure after 30 minutes of supine rest (89+/-3 versus 86+/-2 mm Hg) or in serum lipids and resting plasm a epinephrine and norepinephrine. However, in group-99 resting plasma epinephrine showed a positive hyperbolic relation to resting diastolic blood pressure (r=.73, P=.004) and a negative hyperbolic relation to the ratio of high-density lipoprotein cholesterol to total cholesterol (r=-.75, P=.002). None of these correlations were present in the two other groups. Furthermore, the three groups differed in heart rate res ponses (P<.0005) and systolic (P<.0005) and diastolic (P<.05) blood pr essure responses to mental arithmetic challenge, group-99 being hyperr eactive compared with the other two groups. Plasma epinephrine and nor epinephrine responses to mental arithmetic challenge and blood pressur e responses to the cold presser test did not differ. However, changes in mean blood pressure showed a positive hyperbolic relation to plasma epinephrine during mental arithmetic challenge in group-99 (r=.81, P= .0004) but not in the two other groups. These findings support a link between high screening blood pressure, specific hyperreactivity to men tal stress, and catecholamine-sensitive coronary risk factors.