Tanaka K, Yoshimura T, Sumida S, Mitsuzono R, Tanaka S, Konishi Y, Watanabe H, Yamada T, Maeda K
Eur J Appl Physiol Occup Physiol. 1986;55(4):356-61. doi: 10.1007/BF00422733.
Exercise-induced alterations in cardiac function during graded cycling with submaximal and maximal intensities were studied in 13 trained and 13 untrained young men. Stroke volume (SV) and stroke index (SI) at rest and during submaximal and maximal exercise, determined by impedance cardiography, were consistently greater in the trained than in the less fit group. Training-induced bradycardia was evident in the trained group at rest and during submaximal exercise. Even when SV and SI were compared at the same absolute heart rate and left ventricular ejection time, those for the trained group were markedly greater than those for the untrained. SV for the untrained group was relatively diminished above the work rate corresponding to the anaerobic threshold. The difference in SV during exercise may be attributed to inadequate filling due to the smaller stretch of myocardial fibers in diastole and/or lesser systolic emptying of the left ventricle due to the reduced myocardial contractility in systole of untrained individuals.
在13名受过训练和13名未受过训练的年轻男性中，研究了次最大强度和最大强度分级骑行运动期间运动诱发的心脏功能变化。通过阻抗心动图测定，训练组在静息、次最大强度运动和最大强度运动时的每搏输出量（SV）和每搏指数（SI）始终高于健康状况较差的组。训练引起的心动过缓在训练组静息和次最大强度运动时很明显。即使在相同的绝对心率和左心室射血时间下比较SV和SI，训练组的数值也明显高于未训练组。未训练组的SV在对应于无氧阈值的工作率以上相对降低。运动期间SV的差异可能归因于未训练个体舒张期心肌纤维伸展较小导致的充盈不足和/或收缩期心肌收缩力降低导致的左心室收缩期排空较少。
