To study the relationship between vital capacity and helium-oxygen mixture inspiration and altitude environment to explore changes of vital capacity and expiratory reserve volume (ERV).

• 目的 :比较肺容量对氦氧混合气体和对高原环境的反应 ,探讨呼吸氦氧混合气体后肺活量 ,尤其是补呼气容积大幅增高的现象 ;