Goodman J M, McLaughlin P R, Liu P P
Faculty of Physical Education and Health, University of Toronto, 55 Harbord Street, Toronto, Ontario, Canada M5S 2W6.
Clin Sci (Lond). 2001 May;100(5):529-37.
We assessed left ventricular systolic and diastolic performance during and after prolonged exercise under controlled conditions in a group of healthy, trained men. Previous studies have examined the effects of prolonged effort on left ventricular function, yet it remains unclear whether or not left ventricular dysfunction (e.g. cardiac fatigue) can be produced under such conditions. We studied 15 healthy men, aged 27+/-1 years (mean+/-S.E.M.). Subjects exercised on bicycles at a constant work rate (60% of maximum oxygen uptake per min) for 150 min. Measurements of gas exchange, blood pressure and haematocrit were obtained, concurrent with the assessment of left ventricular function using equilibrium radionuclide angiography, at rest, during exercise (every 30 min) and after 30 min of recovery. Fluid replacement was provided and monitored during the exercise period. The baseline resting and exercise ejection fractions were 66+/-2% and 78+/-2% respectively. During exercise, subjects consumed 1816+/-136 ml of fluid, and the haematocrit had increased at 120 min of exercise (from 47.2%+/-0.6 to 49.9+/-0.8%; P<0.05). There was no change in either systolic or diastolic blood pressure throughout the exercise period, but heart rate drifted upwards from 141+/-2 beats/min after 30 min to 154+/-3 beats/min after 150 min (P<0.05). There was a small decline (8%; P<0.05) in end-diastolic volume at 150 min. No changes were observed in left ventricular ejection fraction, the pressure/volume ratio or end-systolic volume. After 30 min of sitting in recovery, heart rate was still higher than the pre-exercise value (84+/-3 compared with 69+/-2 beats/min; P<0.05), as were measures of peak filling rate and time to peak filling (P<0.05). The ejection fraction in the post-exercise recovery period was similar to the pre-exercise value. The results indicate that prolonged exercise of moderate duration may not induce abnormal left ventricular systolic function or cardiac fatigue during exercise.
我们在可控条件下，对一组健康、经过训练的男性进行长时间运动期间及之后的左心室收缩和舒张功能进行了评估。以往的研究探讨了长时间运动对左心室功能的影响，但在此类条件下是否会产生左心室功能障碍（如心脏疲劳）仍不明确。我们研究了15名健康男性，年龄为27±1岁（均值±标准误）。受试者以恒定工作率（每分钟最大摄氧量的60%）骑单车运动150分钟。在静息状态、运动期间（每30分钟一次）以及恢复30分钟后，进行气体交换、血压和血细胞比容的测量，并同时使用平衡放射性核素血管造影评估左心室功能。运动期间提供并监测补液情况。静息和运动时的基线射血分数分别为66±2%和78±2%。运动期间，受试者消耗了1816±136毫升液体，运动120分钟时血细胞比容升高（从47.2%±0.6升至49.9±0.8%；P<0.05）。整个运动期间收缩压和舒张压均无变化，但心率从30分钟后的141±2次/分钟逐渐上升至150分钟后的154±3次/分钟（P<0.05）。150分钟时舒张末期容积有小幅下降（8%；P<0.05）。左心室射血分数、压力/容积比或收缩末期容积均未观察到变化。恢复坐姿30分钟后，心率仍高于运动前值（分别为84±3次/分钟和69±2次/分钟；P<0.05），峰值充盈率和达到峰值充盈时间的测量值也是如此（P<0.05）。运动后恢复期的射血分数与运动前值相似。结果表明，适度时长的长时间运动在运动期间可能不会诱发异常的左心室收缩功能或心脏疲劳。
