The relationship between body mass index, blood pressure and pulse rate among normotensive and hypertensive participants in the third National Health and Nutrition Examination Survey (NHANES)

Obesity is associated with high insulin and leptin levels. Studies also suggest that high levels of insulin and leptin increase sympathetic nervous system (SNS) activity and engender increased chronotropy, vasoconstriction and antinatriuresis that may contribute to the pathogenesis of obesity related hypertension. Sympathetic modulation of cardiovascular responses requires good baroreceptor sensitivity and optimal vascular compliance. The vascular changes associated with isolated systolic hypertension (ISH) have been shown to modify baroreceptor sensitivity and vascular compliance and may mitigate sympathetic modulation of cardiovascular responses and attenuate the hypertensive effect of obesity. The purpose of this study is to examine the differences in the relationship between body mass index, pulse rate (PR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) among participants with normal blood pressure and ISH using data from the third National Health and Nutrition Examination Survey. Data from 13,761 non-institutionalized adults 18 years and older not receiving antihypertensive therapy were analyzed. Results showed that PR, SBP and DBP increase with increasing BMI. The rise in PR, SBP and DBP with BMI is higher among participants with normal blood pressure than among those with ISH. We concluded that increasing level of obesity is associated with a rise in pulse rate and blood pressure but the effect of obesity on blood pressure and pulse rate might be weaker among participants with ISH.