Heart rate as a predictor of future blood pressure in schoolchildren

Heart rate (HR) has been shown to predict future blood pressures (BP) in st udies in adults. We explored the relation of HR to future BP levels in a co hort of 344 black and 456 white schoolchildren ages 5 to 19 years, to exami ne the hypothesis that HR predicts subsequent BP even very early in life. A fter making baseline measurements, BP was assessed longitudinally 1 to 24 a dditional times (mean = 8.25) after the baseline period, at intervals of ap proximately 6 months. We found that HR was significantly related to future diastolic BP in the black boys (P =.016) after adjusting for baseline diast olic BP, age, and body mass index, but not in the black girls or in the whi te children. Because HR is reflective of sympathetic nervous system (SNS) a ctivity that in turn can be related to the renin-angiotensin system (RAS), we also explored the relation of HR to the RAS by studying relationships to variants in the angiotensinogen gene and the angiotensin I-converting enzy me (ACE) gene. We found a significantly positive relationship of HR to the presence of the deletion allele of the ACE gene (P =.0015), but, again, onl y in the black boys. Because blacks in general appear to retain additional sodium when compared with whites, the SNS, as reflected in the HR, may infl uence BP more when individuals have increased sodium retention. In summary, baseline HR predicted future diastolic BP in the black boys but not in the black girls or in the white children. Am J Hypertens 2000;13:1082-1087 (C) 2000 American Journal of Hypertension, Ltd.