The orthostatic blood pressure change and its influence factors in young students

Objective To investigate the changes of orthostatic blood pressure and heart rate after standing for 3 min and the influence factors in young students.Methods Three hundred seventeen young students 165 males and 152 females,aged（21.5±1.0） years old from grade 2007 in Medical College of Nanchang University were enrolled into this study.The blood pressure（BP） and heart rate（HR） were measured by automatic oscillometric devices when supine for 10 min and when standing for 3 min respectively,and their differences were recorded as ΔBP and ΔHR.Orthostatic hypertension（OHT） was defined as ΔBP≥10 mm Hg,orthostatic hypotension（OH） was ΔBP≤-10 mm Hg,and normal orthostatic BP response（ONT） was ΔBP between OHT and OH.The detection rates were calculated.And the association between orthostatic blood pressure changes and age,sex,athletic habit,family history of hypertension,height,body mass,and body mass index was analyzed.Results The systolic and diastolic BP（SBP and DBP） when standing were significantly higher than those when supine SBP（116.8±12.9） vs（113.8±11.9）mm Hg;DBP（71.4±8.2） vs（66.3±8.3）mm Hg,all P＜0.05.The prevalence of OHT and OH in SBP was 16.4% and 3.8%,and that in DBP was 20.5% and 3.5% respectively.Either SBP or DBP,the detection rate of OH in female was higher than that in male,while the rate of OHT in male was higher than that in female.As to the supine blood pressure,OH group was the most common followed by ONT,the lowest was OHT.Linear regression analysis demonstrated a negative relationship between supine SBP and ΔSBP（r=-0.165,P＜0.05）,and between supine DBP and ΔDBP（r=-0.465,P＜0.05）.ΔSBP correlated negatively with supine SBP and female,while ΔDBP correlated negatively with supine DBP and female as indicated by multivariate analysis.Conclusion Sex and supine BP level are associated with the prevalence of OHT and OH in young cohort.