Bogaard H J, Woltjer H H, Dekker B M, van Keimpema A R, Postmus P E, de Vries P M
Department of Pulmonary Medicine, Academic Hospital VU, Amsterdam, The Netherlands.
Eur J Appl Physiol Occup Physiol. 1997;75(5):435-42. doi: 10.1007/s004210050185.
Whereas with advancing age, peak heart rate (HR) and cardiac index (CI) are clearly reduced, peak stroke index (SI) may decrease, remain constant or even increase. The aim of this study was to describe the patterns of HR, SI, CI, arteriovenous difference in oxygen concentration (Ca-vO2), mean arterial pressure (MAP), systemic vascular resistance index (SVRI), stroke work index (SWI) and mean systolic ejection rate index (MSERI) in two age groups (A: 20-30 years, n = 20; B: 50-60 years n = 20). After determination of pulmonary function, an incremental bicycle exercise test was performed, with standard, gas-exchange measurements and SI assessment using electrical impedance cardiography. The following age-related changes were found: similar submaximal HR response to exercise in both groups and a higher peak HR in A than in B[185 (SD 9) vs 167 (SD 14) beats.min-1, P < 0.0005]; increase in SI with exercise up to 60-90 W and subsequent stabilization in both groups. As SI decreased towards the end of exercise in B, a higher peak SI was found in A [57.5 (SD 14.0) vs 43.6 (SD 7.7) ml.m-2, P < 0.0005]; similar submaximal CI response-to exercise, higher peak CI in A [10.6 (SD 2.5) vs 7.2 (SD 1.3) 1.min-1.m-2, P < 0.0005]; no differences in Ca-vO2 during exercise; higher MAP at all levels of exercise in B; higher SVRI at all levels of exercise in B; lower SWI in B after recovery; higher MSERI at all levels of exercise in A. The decrease in SI with advancing age would seem to be related to a decrease in myocardial contractility, which can no longer be compensated for by an increase in preload (as during submaximal exercise). Increases in systemic blood pressure may also compromise ventricular function but would seem to be of minor importance.
随着年龄增长，心率峰值（HR）和心脏指数（CI）明显降低，每搏输出指数（SI）可能降低、保持不变甚至升高。本研究的目的是描述两个年龄组（A组：20 - 30岁，n = 20；B组：50 - 60岁，n = 20）中心率、每搏输出指数、心脏指数、动静脉氧浓度差（Ca - vO2）、平均动脉压（MAP）、全身血管阻力指数（SVRI）、每搏功指数（SWI）和平均收缩射血率指数（MSERI）的变化模式。在测定肺功能后，进行递增式自行车运动试验，采用标准的气体交换测量方法，并使用电阻抗心动描记法评估每搏输出指数。发现了以下与年龄相关的变化：两组运动时次极量心率反应相似，A组的心率峰值高于B组[185（标准差9）对167（标准差14）次·分钟-1，P < 0.0005]；两组运动至60 - 90瓦时每搏输出指数均升高，随后保持稳定。由于B组运动接近尾声时每搏输出指数降低，A组的每搏输出指数峰值更高[57.5（标准差14.0）对43.6（标准差7.7）毫升·平方米-2，P < 0.0005]；两组运动时次极量心脏指数反应相似，A组的心脏指数峰值更高[10.6（标准差2.5）对7.2（标准差1.3）升·分钟-1·平方米-2，P < 0.0005]；运动期间动静脉氧浓度差无差异；B组在所有运动水平时平均动脉压更高；B组在所有运动水平时全身血管阻力指数更高；恢复后B组的每搏功指数更低；A组在所有运动水平时平均收缩射血率指数更高。随着年龄增长每搏输出指数降低似乎与心肌收缩力下降有关，而这种下降无法通过增加前负荷（如次极量运动时）来代偿。全身血压升高也可能损害心室功能，但似乎不太重要。
