Eleven healthy subjects received an intravenous infusion of angiotensin that raised their mean arterial blood pressure to the level observed in 15 patients with untreated essential hypertension. A hemodynamic study was carried out in both groups at rest and during a standardized exercise load in the sitting position. The hypertensive patients responded to exercise with significantly steeper increases of both the systolic, mean and diastolic arterial blood pressures than the angiotensin-treated subjects. There were no significant differences between the two groups in terms of heart rate, cardiac output and systemic vascular resistance, but the actual level of the systemic vascular resistance during exercise was significantly higher in the hypertensive patients. These results suggest that increased angiotensin blood levels are not responsible for the exaggerated blood pressure increase on exercise in patients with arterial hypertension.