Department of Medical Sciences, Sports Physiology Laboratory, University of Cagliari, Cagliari, Italy;
Am J Physiol Heart Circ Physiol. 2013 Nov 1;305(9):H1387-96. doi: 10.1152/ajpheart.00397.2013. Epub 2013 Aug 30.
The aim of the present study was to test the contribution of stroke volume (SV) in hemodynamic response to muscle metaboreflex activation in healthy individuals. We hypothesized that an acute decrease in cardiac afterload and preload due to the administration of a vasodilating agent could reduce postexercise muscle ischemia (PEMI)-induced SV response. Ten healthy males (age 33.6 ± 1.3 yr) were enrolled and randomly assigned to the following study protocol: 1) PEMI session, 2) control exercise recovery (CER) session, 3) PEMI after sublingual administration of 5 mg of isosorbide dinitrate (ISDN), and 4) CER after ISDN. Central hemodynamics were evaluated by means of impedance cardiography. The main findings were a blunted SV response during metaboreflex following acute arterial and venous vasodilation, associated with a reduction in cardiac diastolic time and filling, and a decrement of systemic vascular resistance. These hemodynamic changes restrain blood pressure response during metaboreflex activation. Our results indicate that hemodynamic response to metaboreflex activation is a highly integrated phenomenon encompassing complex interplay between heart rate, cardiac performance, preload, and afterload and that impairment of one or more of these parameters leads to altered hemodynamic response to metaboreflex.
本研究旨在测试健康个体中每搏量（SV）在肌肉代谢反射激活的血液动力学反应中的作用。我们假设，由于给予血管扩张剂，心后负荷和前负荷的急性下降可能会降低运动后肌肉缺血（PEMI）诱导的 SV 反应。招募了 10 名健康男性（年龄 33.6±1.3 岁），并随机分为以下研究方案：1）PEMI 会议，2）对照运动恢复期（CER）会议，3）舌下给予 5mg 硝酸异山梨酯（ISDN）后的 PEMI 会议，以及 4）ISDN 后的 CER 会议。通过阻抗心动图评估中心血液动力学。主要发现是在急性动静脉血管扩张后代谢反射时 SV 反应减弱，与舒张时间和充盈减少以及全身血管阻力降低有关。这些血液动力学变化抑制了代谢反射激活时的血压反应。我们的结果表明，代谢反射激活的血液动力学反应是一个高度综合的现象，包括心率、心脏性能、前负荷和后负荷之间的复杂相互作用，而这些参数中的一个或多个参数的损伤会导致代谢反射的血液动力学反应改变。
