Shimizu N, Koike A, Koyama Y, Kobayashi K, Marumo F, Hiroe M
Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
Jpn Circ J. 1999 Jun;63(6):459-66. doi: 10.1253/jcj.63.459.
The effect of exercise intensity on gas exchange kinetics was investigated during exercise and recovery, as well as the relationship between the kinetics during exercise and recovery. Twenty-three patients with a history of anterior myocardial infarction performed low-intensity (38.7+/-8.3 W) and high-intensity (68.8+/-15.0 W) exercise for 6 min. The time constants of oxygen uptake (VO2), carbon dioxide output (VCO2) and minute ventilation (VE) were significantly prolonged during high intensity exercise compared with low-intensity exercise (61.2+/-8.6 vs 52.3+/-10.3 s, p<0.005 for the time constant of VO2). The time constant of VO2 was similar during exercise and during recovery from exercise of high (61.2+/-8.6 vs 66.2+/-12.2 s) as well as low intensity (52.3+/-10.3 vs 55.0+/-10.1 s). However, the time constants of VCO2 and heart rate were significantly shorter during recovery than during exercise. The time constants of VCO2 and VE were significantly longer than that of VO2 during both exercise and recovery. In the present study, it was found that (1) the gas exchange kinetics were influenced by the intensity of exercise; (2) the kinetics during recovery did not necessarily reflect the kinetics during exercise except for VO2; and (3) the kinetics of VCO2 and VE were delayed as compared with the VO2 kinetics. These characteristics should be taken into account when using gas exchange kinetics to estimate cardiopulmonary responses to exercise in patients with left ventricular dysfunction.
研究了运动强度对运动及恢复过程中气体交换动力学的影响，以及运动和恢复过程中动力学之间的关系。23名有前壁心肌梗死病史的患者进行了6分钟的低强度（38.7±8.3瓦）和高强度（68.8±15.0瓦）运动。与低强度运动相比，高强度运动期间氧摄取（VO2）、二氧化碳排出（VCO2）和分钟通气量（VE）的时间常数显著延长（VO2时间常数：61.2±8.6秒对52.3±10.3秒，p<0.005）。高强度运动时及从高强度运动恢复过程中VO2的时间常数相似（61.2±8.6秒对66.2±12.2秒），低强度运动时及从低强度运动恢复过程中VO2的时间常数也相似（52.3±10.3秒对55.0±10.1秒）。然而，恢复过程中VCO2和心率的时间常数明显短于运动期间。运动和恢复过程中，VCO2和VE的时间常数均显著长于VO2的时间常数。在本研究中，发现：（1）气体交换动力学受运动强度影响；（2）除VO2外，恢复过程中的动力学不一定反映运动期间的动力学；（3）与VO2动力学相比，VCO2和VE的动力学延迟。在使用气体交换动力学评估左心室功能障碍患者对运动的心肺反应时，应考虑这些特征。
