Daily response of blood pressure to day-to-day variation of urinary sodiumto potassium ratio

The relationship between blood pressure and urinary sodium-to-potassium (Na /K) ratio was assessed in eight healthy men, none of whom used antihyperten sive medications. Blood pressure and urinary sodium and potassium concentra tions were measured for 11 to 33 days without any dietary restriction. For two of the eight subjects, the urinary Na/K ratio significantly correlated with systolic blood pressure (r=0.70 and 0.45, respectively), and in one of the two subjects, the urinary ratio also positively correlated with diasto lic blood pressure (r=0.72). In the others, no relationship between the rat io and blood pressure was observed (r=-0.24 to 0.26). The results indicate that, in some individuals, the daily variation of urinary Na/K ratio is clo sely correlated with day-to-day changes in blood pressure level, and sugges t that the urinary Na/K ratio is useful in the management of the daily sodi um and potassium intake balance of hypertensive patients who need to restri ct salt intake.