Sympathetic nervous system and exercise tolerance response in normotensive and hypertensive adolescents.

Comparative evaluation of isometric and dynamic exercise performance in normotensive, borderline hypertensive and hypertensive adolescents was made. Hemodynamic changes were correlated with level of adrenergic sympathetic nervous system activity as measured by plasma epinephrine and norepinephrine values. No significant intergroup differences were found with respect to isometric exercise with the exception of high peak isometric exercise heart rates and plasma epinephrine levels in the patients with significant hypertension. During dynamic treadmill testing, patients with the most marked hypertension demonstrated a statistically significantly greater tachycardia response to exercise that correlated with highest peak exercise epinephrine levels. The most hypertensive systolic dynamic exercise response was evidenced in the borderline hypertensive group in which peak exercise norepinephrine values were significantly higher than in other groups. Maximal exercise serum lactate levels were higher in hypertensive patient groups than in normotensive subjects. Altered hemodynamic response to peak dynamic exercise appears to exist in adolescents with borderline and significant hypertension and is in part mediated by altered activity of the sympathetic nervous system.