Blood Pressure Responses to Extremes of Sodium Intake in Normal Man 1

Abstract

Summary

The relationship between blood pressure and the state of salt balance was evaluated at four levels of salt intake (10 mEq/day, 300 mEq/day, 800 mEq/day, and 1500 mEq/day) in eight normal men. Increasing salt intake resulted in progressive increases in weight, blood pressure, potassium excretion, and creatinine clearance, while plasma renin activity and plasma aldosterone concentration decreased. Cardiac output increased with increasing salt intake, while calculated systemic vascular resistance decreased. The curve defining the relationship between salt excretion and blood pressure was derived. These results support the conceptual framework integrating blood pressure regulation through the final common pathway of renal salt excretion. Moreover, they underscore the importance of salt regulation in the pathogenesis of hypertension.