Dynamic exercise response in hypertensive adolescent on clonidine therapy: clonidine therapy in adolescent...

The cardiovascular response to dynamic exercise is compared in 16 normotensive control adolescents (C), 15 untreated hypertensive (H) adolescents, and 14 hypertensive adolescents on clonidine therapy (HRx) for blood pressure control. All subjects exercised to exhaustion (heart rate (HR) = 200) on a treadmill by Bruce protocol. Blood pressure and HR were monitored during exercise and recovery. Systolic pressure was greater in H and HRx and than C at baseline, exercise, and recovery (P less than 0.01) as was the product of systolic blood pressure times heart rate (SBP X HR). Diastolic blood pressure (DBP) was greater in H and HRx at base line but decreased in all subjects (C, H, and HRx) during vigorous exercise. Our results indicate that H and HRx adolescents have higher SBP and HR at rest and exercise consistent with a hyperkinetic circulatory state; DBP response to exercise is normal in H adolescents; and, clonidine in HRx lowered baseline HR and blood pressure but did not alter a normal exercise response.