FACTORS AFFECTING EXERCISE INDUCED BRONCHOSPASM

哮喘是第二个主要原因的功能限制在下 45岁年龄组。 急性加重的疾病，由物理 这些患者易受影响的运动可能会进一步加剧 寒冷和/或干燥的环境。 确凿证明 支气管收缩的机制是气道的热量损失， 从而冷却呼吸道。 然而，在锻炼过程中， 哮喘患者和正常受试者都表现出呼气增加 最有可能是由于支气管扩张和弹性增加引起的流动 肺回缩。 因此，该机制似乎 负责这种增加的气流作为一个竞争机制 运动诱发支气管痉挛（EIB）。 游泳训练整体下降 哮喘残疾评分和药物使用，但不会减少EIB 严重性。 跑步训练似乎可以实现这些好处， 降低EIB。 我们假设，这两种形式之间的差异 训练是适应性呼吸刺激的差异。 运行结果 在由于自适应过程导致气道冷却阈值增加中， 呼吸道反复发作的呼吸过度在一个广泛的范围 的气候条件。 温暖潮湿的游泳池环境将 不能提供有效的适应性刺激。 本项目的目的是 评估身体健康和/或气道适应在EIB中的作用， 通过游泳和跑步训练加上三种方式的正常二氧化碳呼吸过度来降温 交叉设计

Asthma is the second leading cause of functional limitation in the under 45-year-old age group. The acute exacerbation of symptomes by physical exertion to which these patients are susceptible can be further exacerbated by a cold and/or dry environment. There is compelling evidence that the mechanism for bronchoconstriction is loss of heat from the airways with consequent cooling of the respiratory tract. During exercise, however, both asthnatics and normal subjects demonstrate an increased expiratory flow which is most likely due to both bronchodilation and increased elastic recoil of the lung. It would appear, therefore, that the mechanism responsible for this increase in airflow serves as a competetive mechanism to exercise-induced bronchospasm (EIB). Swim training decreases overall asthma disability scores and use of medicine but does not diminish EIB severity. Run training appears to accomplish these benefits and also to reduce EIB. We hypothesize that the difference between these two forms of training is a difference in adaptive respiration stimulus. Running results in an increase in threshold to airway cooling due to an adaptive process in the respiratory tract from repeated bouts of hyperpnea under a broad range of climatic conditions. The warm, humid swimming pool environment would not provide a sifficiently adaptive stimulus. The aim of this project is to asses the roles in EIB of physical fitness and/or airway adaptation to cooling via swim and run training plus eucapnic hyperpnea in a three-way crossover design.