Hwang S K, Kim D W, Ko S K, Kim C K
Department of Physiology, Yonsei University College of Medicine, Seoul, Korea.
Yonsei Med J. 1991 Mar;32(1):58-63. doi: 10.3349/ymj.1991.32.1.58.
Nine athletes and ten nonathletes were selected randomly to study the changes of cardiac function during exercise by impedance cardiography. The speed of the treadmill was maintained at 3.4 mph, and its grade was increased by 1% (Balke protocol). The exercise was continued until the target heart rate (THR), 85% of maximum oxygen uptake (VO2max). The measured parameters for pre- and post-exercise were stroke volume (SV), heart rate (HR), and cardiac output (CO). Average stroke volume of athletes at pre-exercise, 71.1 ml, was higher than that of nonathletes, 64.6 ml, and stroke volume of the former at post-exercise, 97.0 ml, was also higher than that of the latter, 85.2 ml. Therefore, despite the lower heart rate, cardiac outputs of athletes at pre- and post-exercise, 4.98 and 16.3 L/min, were higher than those of nonathletes, 4.87 and 14.2 L/min. For the second phase of the study, cardiac outputs of three subjects were measured during the continuous treadmill exercise with newly developed electrodes and shoes for minimizing motion artifact. Though there were several studies measuring cardiac output during continuous bicycle exercise, this is thought to be the first study in the world measuring cardiac output during continuous treadmill exercise without aid of ensemble averaging.
随机选取9名运动员和10名非运动员，通过阻抗心动描记法研究运动过程中心脏功能的变化。跑步机速度保持在3.4英里/小时，坡度以1%的幅度增加（巴尔克方案）。运动持续进行直至达到目标心率（THR），即最大摄氧量（VO2max）的85%。运动前后测量的参数包括每搏输出量（SV）、心率（HR）和心输出量（CO）。运动员运动前的平均每搏输出量为71.1毫升，高于非运动员的64.6毫升；运动员运动后的每搏输出量为97.0毫升，也高于非运动员的85.2毫升。因此，尽管运动员心率较低，但其运动前后的心输出量分别为4.98升/分钟和16.3升/分钟，高于非运动员的4.87升/分钟和14.2升/分钟。在研究的第二阶段，使用新开发的电极和鞋子，以尽量减少运动伪影，在连续跑步机运动期间测量了三名受试者的心输出量。虽然有几项研究测量了连续自行车运动期间的心输出量，但这被认为是世界上第一项在不借助总体平均的情况下测量连续跑步机运动期间心输出量的研究。
