[Effect of oxygen (FI02: 0.35) on the aerobic capacity in patients with COPD]

Disability in patients with chronic obstructive pulmonary disease has led to the development of rehabilitation programs to increase exercise tolerance.

To determine, if the effect of training can be improved by giving supplemental oxygen during exercise.

Ten male patients with COPD (mean FEV1 = 43.2 +/- 17.1% pred) underwent a five day per week cycle ergometer training program for four weeks at least 45 minutes per day at a constant workload of 80% of their highest achieved workrate--measured in an incremental exercise test before training. At this workrate all patients performed exercise above their anaerobic threshold. Five patients were breathing 35% oxygen during exercise, five were breathing roomair (randomised, single blind). To evaluate and compare the results of training before and after the program all patients performed an incremental exercise test (continuously increasing workrate) with roomair.

In the group breathing 35% O2 during training the maximally achieved power in the incremental exercise test after training was 15.9% higher. In the group breathing roomair during training the maximally achieved power after training was 36.3% higher than before (p < 0.05). This group also showed significant reductions in lactate levels (p < 0.05) after training at the maximum workload achieved in the pre-training test.

Training in the roomair-group resulted in a significant increase in the maximum power and total amount of work. In this group training could induce a physiologic response (increase of aerobic capacity), which was shown by significantly lower lactate levels at a comparable workload.