Description
Empirical research has indicated that adding extra oxygen to the air during a short-term exercise session lowers minute ventilation at comparable work rates and postpones the development of dynamic hyperinflation and related dyspnea. The study aimed to determine whether supplemental oxygen during exercise was superior to medical air in improving endurance capacity and HRQoL, as well as improving maximal walking ability, reducing dyspnea, and increasing daily physical activity in individuals with COPD who were normoxemic at rest and desaturated during exercise. Individuals with COPD who had an oxygen desaturation of <90% on the 6-minute walk test were enrolled in this multicenter study and randomly assigned to an oxygen or air group, independently and concealed. For eight weeks, each of the two groups — the oxygen group and the air group — received 5 l/min-1 gas via concentrators using nasal plugs during their thrice-weekly treadmill and bicycle training. Physical training for each group originally included 10 minutes of stationary cycling at 60% of the peak work rate, determined from the 6MWT, and 20 minutes of treadmill walking at 80% of the average 6MWT pace, under supervision three times a week for eight weeks. Individuals with COPD who had an oxygen desaturation of <90% on the 6-minute walk test were enrolled in this multicenter study and randomly assigned to an oxygen or air group, independently and concealed. By week three, the amount of time spent exercising had increased to a total of 40 minutes (20 minutes of stationary cycling and 20 minutes of treadmill walking). During the training program, work rate (intensity) was raised in accordance with symptoms until dyspnea or rate of perceived exertion (RPE) reached a “moderate” to “somewhat severe” level (i.e., a score of 3-5 on the modified dyspnoea and RPE 0–10 scales).