INDICATORS OF SYMPATHETIC NERVOUS SYSTEM OVERACTIVITY IN HYPERTENSIVES (NERVOUS SYSTEM).

Description

A proposed mechanism of hypertension is sympathetic nervous system overactivity, which may be manifested as elevated catecholamine levels and anger suppression. The purpose of this investigation was to characterize hypertensives based on blood pressure and catecholamine response to exercise and the behavioral variable, anger. The sample consisted of 27 hypertensive (ages 27-67) and 8 normotensive (ages 27-50) subjects. Subjects completed the State-Trait Personality Inventory (which includes the State-Trait Anger Scale) and the Anger Expression Scale. They were given a graded maximal exercise test on a cycle ergometer beginning at 25 watts with workloads increasing by 25 watts every two minutes. Blood pressure (BP) was measured at rest and at the end of each workload. Plasma norepinephrine (NE) and epinephrine (E) were measured via an indwelling catheter at rest, 100 watts, and peak exercise, and analyzed by High Performance Liquid Chromatography. A subgroup of 8 hypertensives were matched for age and fitness level with the normotensives for the purpose of analysis. The findings of this investigation revealed that resting diastolic BP was moderately related to resting NE and E (r =.53 and.47) in the hypertensive subgroup. At peak exercise systolic BP was correlated with NE (r =.53). Although these associations were not statistically significant, they were not observed in the normotensives. At 100 watts systolic BP was highly related to NE in all subjects (r =.76; p $<$.05). Multiple regression analyses on the entire sample showed that age, fitness (peak VO2), and resting systolic BP were small, but significant predictors for resting NE. Peak VO2 was the only significant predictor for NE and E at peak exercise. In hypertensives resting NE and E correlated positively with all anger expression variables. No relationship was observed in normotensives. Resting diastolic BP was related to anger expression in all subjects. Peak diastolic BP during exercise correlated positively with anger-in. None of these relationships were statistically significant, however. The rate of rise of diastolic BP during exercise was negatively correlated with anger-out and positively correlated with anger-in in hypertensives (r = $-.80$ and.80; p $<$.05).

Subjects