Bouquin Heidi, Suojanen Lauri J, Koskela Jenni K, Pietilä Essi, Choudhary Manoj Kumar, Mustonen Jukka T, Pörsti Ilkka H
Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.
Department of Internal Medicine, Tampere University Hospital, Tampere, Finland.
Am J Physiol Heart Circ Physiol. 2025 Mar 1;328(3):H387-H392. doi: 10.1152/ajpheart.00796.2024. Epub 2025 Jan 10.
Increased blood pressure upon standing is considered a cardiovascular risk factor. We investigated the reproducibility of changes in aortic blood pressure, heart rate, stroke volume, cardiac output, and systemic vascular resistance during three passive head-up tilts (HUT) in 223 participants without cardiovascular medications (mean age 46 yr, BMI 28 kg/m, 54% male). The median time gap between the first and the second HUT was 9 wk and the second and the third HUT was 4 wk. We utilized whole body impedance cardiography and radial artery tonometry as methods. The participants were divided into quartiles of the changes in each hemodynamic variable during the first HUT, and the reproducibility of these changes was tested during successive HUTs. During the first HUT, significant differences were present in all between-quartile comparisons ( = 6) of all variables. The differences persisted as follows: reduction of stroke volume in six out of six (6/6) between-quartile comparisons ( < 0.001), decrease in cardiac output ( < 0.001) and increase in heart rate in 5/6 comparisons ( < 0.001), change in systemic vascular resistance in 3/6 comparisons ( < 0.001), change in aortic systolic blood pressure in 1/6 comparisons ( = 0.043), and change in aortic diastolic blood pressure in none ( = 0.266). To conclude, the reproducibility of upright posture-induced changes is high for stroke volume, cardiac output, and heart rate, moderate for systemic vascular resistance, and modest for aortic blood pressure. Although an increase in blood pressure during upright posture may be a cardiovascular risk factor, this effect may be attributed to other underlying hemodynamic variables that exhibit more reproducible posture-related changes. We examined the reproducibility of hemodynamic responses to three passive head-up tilts. The associated changes in stroke volume, cardiac output, and heart rate were highly reproducible. Systemic vascular resistance showed moderate reproducibility, whereas blood pressure changes during upright posture were modestly reproducible. If an exaggerated blood pressure response to upright posture is a cardiovascular risk factor, it is likely attributed to other hemodynamic variables that exhibit more reproducible posture-related changes.
站立时血压升高被认为是一种心血管危险因素。我们在223名未服用心血管药物的参与者（平均年龄46岁，体重指数28kg/m²，54%为男性）中，研究了三次被动头高位倾斜（HUT）期间主动脉血压、心率、每搏量、心输出量和全身血管阻力变化的可重复性。第一次和第二次HUT之间的中位时间间隔为9周，第二次和第三次HUT之间为4周。我们采用全身阻抗心动图和桡动脉压测量法。根据第一次HUT期间每个血流动力学变量的变化将参与者分为四分位数，并在连续的HUT期间测试这些变化的可重复性。在第一次HUT期间，所有变量的所有四分位数间比较（n = 6）均存在显著差异。差异持续如下：每搏量在6/6次四分位数间比较中降低（P < 0.001），心输出量降低（P < 0.001），心率在5/6次比较中升高（P < 0.001），全身血管阻力在3/6次比较中变化（P < 0.001），主动脉收缩压在1/6次比较中变化（P = 0.043），主动脉舒张压无变化（P = 0.266）。总之，直立姿势引起的每搏量、心输出量和心率变化的可重复性高，全身血管阻力的可重复性中等，主动脉血压的可重复性一般。虽然直立姿势期间血压升高可能是一种心血管危险因素，但这种效应可能归因于其他潜在的血流动力学变量，这些变量表现出与姿势相关的更具可重复性的变化。我们研究了对三次被动头高位倾斜的血流动力学反应的可重复性。每搏量、心输出量和心率的相关变化具有高度可重复性。全身血管阻力显示出中等可重复性，而直立姿势期间的血压变化具有一般可重复性。如果对直立姿势的血压反应过度是一种心血管危险因素，那么很可能归因于其他表现出与姿势相关的更具可重复性变化的血流动力学变量。
