The Relationship between Cold-Induced Natriuresis and Arterial Blood Pressure in Man

Abstract

In 9 naked healthy volunteers, exposed to cold of +15 °C for 60 min, changes in arterial blood pressure, internal body temperature, renal hemodynamics, urine flow and osmolality, and fractional sodium excretion were studied in both hydropenia and water diuresis. No change in urine flow or in U/P osmolality ratio was found in cold. Fractional sodium excretion was significantly increased and significantly correlated to the cold-induced rise in arterial blood pressure. Since no changes in GFR were observed in cold, the results suggest that a cold-induced depression of renal tubular sodium re-absorption is the cause of cold-induced natriuresis in man.

Key Words:

• Blood pressure
• cold exposure
• hydropenia
• sodium excretion
• water diuresis