Hemodynamic responses during exercise at and above VO2max in swine.
Hemodynamic responses during exercise at and above VO2max in swine.
复制标题
猪在最大摄氧量及以上运动期间的血流动力学反应。
DOI：
10.1152/jappl.1990.69.5.1587
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Armstrong,RB
中科院分区：
文献类型：
--
作者：
Norton,KI;Delp,MD;Duan,C;Warren,JA;Armstrong,RB
当小型猪在电动跑步机上以高水平跑步时，测量其平均动脉压（Pa）、心率、心输出量（Q）和Q分布（使用放射性标记微球）。每只动物跑两次：一次是在最大摄氧量（VO 2 max）运动期间，一次是在估计需要约115%VO2max的强度下。其目的是评估这些心血管变量，以确定是否计算出的血流阻力在超极量运动期间是不同的，在最大的运动。共解剖了114个组织/器官进行血流分析。Pa和Q在两种运动条件之间没有改变。在62块骨骼肌中，除了一块骨骼肌外，所有骨骼肌的血流量在两种情况下都没有变化，内脏器官和大脑的血流量也没有变化。结果表明，血管阻力是恒定的，在所有这些组织之间的最大和超最大运动强度。在11个冠状动脉采样部位中的7个部位测量到血流量升高。计算的血流阻力表明，在大多数血流升高的样品中，阻力降低。由于在超负荷运动期间心率升高，血流量的增加可能是对更大的心肌功和伴随的O2需求升高的反应。总之，研究表明，在高于VO 2 max的强度下，运动期间大部分组织中的Pa、Q和Q分布保持不变。因此，在由交感神经系统启动的越来越强大的血管收缩驱动和响应于超大运动期间更大的O2需求的升高的局部血管舒张驱动之间发生精确的匹配。（250字处删节）
Mean arterial pressure (Pa), heart rate, cardiac output (Q), and Q distribution (with radiolabeled microspheres) were measured in miniature swine as they ran at high levels on a motor-driven treadmill. Each animal ran on two occasions: once during exercise at maximal O2 uptake (VO2max) and once at an intensity estimated to require approximately 115% VO2max. The purpose was to assess these cardiovascular variables to determine whether the calculated resistance to blood flow during supramaximal exercise was different from that during maximal exercise. A total of 114 tissues/organs were dissected for blood flow analysis. Pa and Q were unaltered between the two exercise conditions. Blood flow to all but one of the 62 skeletal muscles sampled was unchanged between conditions as were the blood flows to the visceral organs and brain. The results demonstrate that vascular resistance was constant in all these tissues between maximal and supramaximal exercise intensities. Elevated blood flows were measured in 7 of the 11 coronary sites sampled. Calculated resistance to blood flow indicated that a decrease in resistance occurred in most of the samples having elevated blood flow. Because heart rate was elevated during the supramaximal exercise, the increase in blood flow was probably in response to the greater myocardial work and concomitant elevation in O2 demand. In summary, it was shown that Pa, Q, and Q distribution in most tissues remained unchanged during exercise at intensities above VO2max. Thus a precise matching occurs between the increasingly powerful vasoconstrictor drive initiated by the sympathetic nervous system and the elevated local vasodilatory drive responding to the greater O2 demand during the supramaximal exercise.(ABSTRACT TRUNCATED AT 250 WORDS)