Sympathetic Activity and Cardiovascular Risk Factors in Young Men in the Low, Normal, and High Blood Pressure Ranges

Abstract

We hypothesized that resting blood pressure is related to sympathetic activity in young men who are unaware of their blood pressure status in high, normal, and low ranges and that there is a relationship between sympathetic activity and coronary risk factors. Forty-three healthy, young men from the 1st [group 1, 106/52±2/2 mm Hg (±SEM), n=15], 50th (group 2, 129/79±2/1 mm Hg, n=15), and 98th to 99th percentile (group 3, 166/97±3/1 mm Hg, n=13) at a blood pressure screening were studied with intraarterial blood pressure, heart rate, and arterial plasma catecholamine responses to a mental, cold pressor, and orthostatic stress test. At baseline, group 3 had significant higher blood pressure (137/74±3/2 mm Hg) than group 2 (126/66±3/2 mm Hg; P <0.01) and group 1 (116/62±2/1 mm Hg; P <0.001). Group 1 had lower systolic blood pressure than group 2 ( P =0.007). Baseline epinephrine and norepinephrine showed a clear positive linear trend ( P <0.05), with the lowest values being in group 1 and highest in group 3. High-density lipoprotein was negatively related to epinephrine ( r =−0.387; P =0.010). Mental stress was the only test that showed significant differences in cardiovascular and sympathetic responses among the groups, where group 3 had a more pronounced response in systolic and diastolic blood pressure and heart rate compared with group 1 ( P <0.001) and group 2 ( P <0.01). Furthermore, we found significant positive linear trends for Δcatecholamines during mental stress across the groups (Δepinephrine P =0.001 and Δnorepinephrine P =0.026, ANOVA). We conclude that resting blood pressure reflects both variation in resting arterial catecholamines and variation in cardiovascular and sympathetic responses specifically to mental stress.