Clark C J, Cochrane L M
Department of Respiratory Medicine, Hairmyres Hospital, Glasgow.
Thorax. 1988 Oct;43(10):745-9. doi: 10.1136/thx.43.10.745.
In view of the lack of objective information on work performance in asthma, a progressive incremental exercise test was carried out in 44 subjects with mild to moderate asthma and 64 normal, healthy subjects matched for habitual activity, to compare cardiorespiratory fitness and to determine the relative contribution of airflow obstruction to exercise limitation. The two groups achieved similar maximum heart rates (mean (SD) 176(12) and 175(10) beats/min). After allowance for confounding factors the asthmatic subjects had a lower maximum oxygen consumption (VO2 max) (by 199 ml min-1) than control subjects. Having asthma also accounted for a significant reduction in anaerobic threshold (125 ml min-1) and oxygen pulse (0.805 ml/beat). There was no correlation of FEV1 with VO2 max, anaerobic threshold, or oxygen pulse either before or after bronchodilator. The dyspnoea index (VE/MVV%) was increased in the asthmatic subjects at peak exercise, but was less than 60% in all subjects at a workload that produced 75% of the predicted maximum heart rate. Thus the asthmatic subjects had a maximum heart rate similar to that of normal subjects but the low VO2 max, anaerobic threshold, and oxygen pulse suggest suboptimal fitness, which was not directly due to airflow obstruction. All had sufficient ventilatory reserve to allow toleration of training at a work intensity adequate to permit improvements in cardiovascular fitness.
鉴于缺乏有关哮喘患者工作表现的客观信息，我们对44名轻度至中度哮喘患者以及64名与哮喘患者日常活动量匹配的正常健康受试者进行了递增式运动试验，以比较心肺适能，并确定气流阻塞对运动受限的相对影响。两组受试者达到的最高心率相似（平均值（标准差）分别为176（12）次/分钟和175（10）次/分钟）。在考虑混杂因素后，哮喘患者的最大摄氧量（VO2 max）低于对照组（低199 ml·min⁻¹）。患有哮喘还导致无氧阈（降低125 ml·min⁻¹）和氧脉搏（降低0.805 ml/次搏动）显著降低。支气管扩张剂使用前后，第一秒用力呼气量（FEV1）与VO2 max、无氧阈或氧脉搏均无相关性。哮喘患者在运动峰值时的呼吸困难指数（VE/MVV%）升高，但在产生预测最大心率75%的工作量下，所有受试者的该指数均低于60%。因此，哮喘患者的最高心率与正常受试者相似，但低VO2 max、无氧阈和氧脉搏表明其适能欠佳，这并非直接由气流阻塞所致。所有受试者都有足够的通气储备，能够耐受达到改善心血管适能所需强度的训练。
