Chen W Y, Weiser P C, Chai H
Scand J Respir Dis. 1979 Jun;60(3):144-50.
Five patients were studied using a randomly assigned sequence of four inspired-air conditions during strenuous treadmill exercise for 10 min. The four inspired-air conditions were: (1) Cool, dry room air (CDA) at 23 degrees C with 3 mg of water and 7.3 cal of heat content/l, (2) over-saturated air (OSA) at room temperature containing 43 mg water and 16.3 cal/l, (3) hot, dry air (HDA) at 120 degrees C having 3 mg water and 24.4 cal/l, and (4) warm, humidified air (WHA) at 37 degrees C with 43 mg water and 34.7 cal/l. Using inspired-air CDA and OSA, all patients manifested exercise-induced asthma (EIA) while forced expiratory volume in 1 sec (FEV1) and maximal mid-expiratory flow (MMEF) decreased to an average of 81% and 63% of the baseline when breathing CDA and to 83% and 71% of the baseline when breathing OSA. With WHA, EIA was clearly prevented while the post-exercise FEV1 and MMEF were 101% and 103% of baseline, respectively. With HDA, the post-exercise FEV1 and MMEF were 95% and 86% of baseline, respectively. Analysis of variance revealed that the post-exercise pulmonary function changes had resulted solely from respiratory heat loss and not from water loss or from interaction of heat and water losses. These results indicate that exercise-induced asthma is associated with airway cooling incurred during exercise rather than airway dehydration.
对5名患者进行了研究，在剧烈的跑步机运动10分钟期间，使用随机分配的四种吸入空气条件序列。这四种吸入空气条件分别为：（1）23摄氏度的凉爽、干燥室内空气（CDA），含水量3毫克，热含量7.3卡路里/升；（2）室温下的过饱和空气（OSA），含水量43毫克，热含量16.3卡路里/升；（3）120摄氏度的热、干燥空气（HDA），含水量3毫克，热含量24.4卡路里/升；（4）37摄氏度的温暖、加湿空气（WHA），含水量43毫克，热含量34.7卡路里/升。使用吸入空气CDA和OSA时，所有患者均表现出运动诱发哮喘（EIA），而在呼吸CDA时，1秒用力呼气量（FEV1）和最大呼气中期流量（MMEF）平均降至基线的81%和63%，呼吸OSA时降至基线的83%和71%。使用WHA时，EIA明显得到预防，运动后FEV1和MMEF分别为基线的101%和103%。使用HDA时，运动后FEV1和MMEF分别为基线的95%和86%。方差分析显示，运动后肺功能变化完全是由呼吸热损失导致的，而不是由水分损失或热与水分损失的相互作用导致的。这些结果表明，运动诱发哮喘与运动期间发生的气道冷却有关，而不是与气道脱水有关。
