Abstract: Objective To compare the effect of breathing oxygen or air on respiratory function training for chronic obstructive pulmonary disease (COPD). Methods 32 patients with stable COPD, pulmonary function Ⅱ～Ⅳ, were divided into 2 groups: oxygen (10males and 6 females and air (12 males and 4 females). All the patients participated in a standardized pulmonary rehabilitation program. They were assessed with St. George respiratory questionnaire, pulmonary function test, 6-minute walking distance, cardiopulmonary exercise test and Borg scale, maximal oxygen consumption (VO₂max) before and after training. Results After 8 weeks of pulmonary rehabilitation, the VO₂max in oxygen group increased compared with that of the air. Conclusion Supplying oxygen during training can increase the tolerance of COPD patients.

Key words: chronic obstructive pulmonary disease (COPD), maximal oxygen consumption, pulmonary rehabilitation, oxygen supplement