Influence of Angiotensin on the Hemodynamic Response to Exercise in Normotensive Subjects

The effect of exercise on the systemic hemodynamic response in 11 healthy men has been studied before and during an intravenous infusion of angiotensin sufficient to increase the resting mean arterial blood pressure an average of 29%. On exercise in the angiotensin period there was a significantly smaller rise of the systolic pressure than on exercise in the control state, and the response of the diastolic pressure was changed from a moderate increase to a decrease on an average. The increase in mean arterial pressure on exercise was almost abolished, being 4.3 mm Hg during the infusion compared with 20.6 mm Hg before infusion. The rise in cardiac output on exercise was significantly smaller during the angiotensin period, while at the same time there were no significant changes in the behavior of the heart rate, stroke volume, or systemic vascular resistance. The findings indicate that the vasoconstricting effects of angiotensin are largely overcome by the vasodilating effect of exercise in the working muscle groups, but the possibility of relatively increased vasoconstriction in the vascular bed supplying less vitally important tissues is pointed out.