Possible Detection Of Individual Salt-Sensitive Blood Pressure Elevation By 24-Hour Urinary Sodium Excretion And Nighttime Heart Rate

Detection of individual difference in salt-induced blood pressure (BP) elevation is important to know who should reduce salt intake for preventing hypertension, but the diagnosis of salt sensitivity requires a time-consuming protocol for testing BP changes in response to salt loading and depletion. Since WHO-CARDIAC Study indicated BP was higher in the people excreting more 24-hour urinary (24U) salt with higher heart rate (HR), ambulatory BP was monitored in a Korean population to investigate the association of nighttime BP and HR with 24-hour urinary salt excretion for detecting salt sensitivity.Total 101 males and females aged 30 to 61 years were examined for ambulatory BP (by TM2430, A&D, Tokyo, Japan) and 24U collected by aliquot cups.In the participants excreting 24U salt equal to or higher than (≥) the mean, 10.8 g, nighttime systolic and diastolic BP (SBP, DBP), in the group with HR ≥ the mean, 64.7 beats/min (18) were 119.8/77.1 mmHg, significantly higher than 109.2/67.8 mmHg in the group with HR.Significant nighttime BP elevation could be detected by 24U salt ≥ 10 g and nighttime HR ≥ 65 in this Korean population. Collecting 24U by using a simple aliquot cup and monitoring nighttime HR by a wrist watch-type HR detector are expected to detect salt sensitivity also in other populations, as noted in significantly higher BP in 50 CARDIAC Study populations with higher 24U salt and HR than their means.