Thomas S G, Paterson D H, Cunningham D A, McLellan D G, Kostuk W J
Centre for Activity and Ageing, London, Ont., Canada.
Can J Physiol Pharmacol. 1993 Feb;71(2):136-44. doi: 10.1139/y93-019.
Studies of the cardiovascular response to exercise in older subjects have presented conflicting data regarding left ventricular function, the cardiac output-oxygen consumption (Q-VO2) relationship, and the pattern of change in Q, stroke volume (SV), and arteriovenous O2 difference. We have examined the cardiovascular response to submaximal and strenuous exercise in 96 men of mean age 63 years during an incremental treadmill test with Q determined by CO2 rebreathing, and in 12 subjects studied during incremental supine exercise with left ventricular volumes evaluated by radionuclide angiocardiography. During treadmill exercise the Q was approximately 10% lower than reported for younger samples, with a lower intercept of the Q-VO2 relationship. During near-maximal exercise Q was approximately 15 L.min-1, with SV of 95 mL plateauing or showing a small decline in heavy work. Peak arteriovenous O2 difference (150 + mL.L-1) approached values of the young. During the supine exercise SV increased from rest to exercise, with a consistent increase in ejection fraction (rest, 66%, to peak exercise, 76%). In contrast to a prior report, the end-diastolic volume was constant, with the increase of SV attributable to a reduced end-systolic volume. Also, in contrast to a number of reports in older subjects, our findings show only small losses in cardiovascular response, and in left ventricular performance during light through strenuous exercise.
关于老年受试者运动时心血管反应的研究，在左心室功能、心输出量与氧耗量（Q-VO2）关系以及Q、每搏输出量（SV）和动静脉氧分压差的变化模式方面呈现出相互矛盾的数据。我们在递增式跑步机测试中，通过二氧化碳重呼吸法测定Q，对96名平均年龄63岁的男性进行了次最大强度和剧烈运动时心血管反应的研究；并对12名受试者在递增式仰卧运动中进行了研究，通过放射性核素心血管造影评估左心室容积。在跑步机运动期间，Q比年轻样本报告的值低约10%，Q-VO2关系的截距更低。在接近最大强度运动时，Q约为15 L·min-1，SV为95 mL，在重度运动时趋于平稳或略有下降。最大动静脉氧分压差（150 + mL·L-1）接近年轻人的值。在仰卧运动期间，SV从静息状态增加到运动状态，射血分数持续增加（静息时为66%，运动峰值时为76%）。与先前的报告相反，舒张末期容积保持恒定，SV的增加归因于收缩末期容积的减少。此外，与关于老年受试者的一些报告相反，我们的研究结果表明，在轻度至剧烈运动期间，心血管反应和左心室功能仅有微小损失。
