Blood pressure variability and urinary electrolyte excretion in normotensive adults

The principal aim of the present study was to determine the relationship of ambulatory blood pressure (BP) to urinary electrolyte excretion in normotensives. Twenty-five young adults underwent ambulatory BP and heart rate monitoring while collecting urine over 24 h. The correlations of 24 h urine sodium excretion and the ratio of sodium/potassium excretion with systolic BP in the laboratory (r = 0.12 and 0.24), ambulatory awake (r = 0.11 and 0.24), and ambulatory asleep (r = 0.24 and 0.31) settings were all in the positive direction but not significant. However, 24 h sodium excretion did correlate significantly and positively with awake and asleep ambulatory systolic (r = 0.45 and 0.41, P < .05) and diastolic (r = 0.42 and 0.43, P < .05) coefficients of variability. Thus, in normotensives on an unlimited diet, 24 h urinary sodium was more closely related to ambulatory BP variability than to BP level.