Influence of spontaneous pursed lips breathing on walking endurance and oxygen saturation in patients with moderate to severe chronic obstructive pulmonary disease

Objective: To evaluate how spontaneously used pursed lips breathing influences walking endurance, oxygen saturation and dyspnoea in patients with moderate to severe chronic obstructive pulmonary disease. Design: A randomized open-label, cross-over study of chronic obstructive pulmonary disease patients participating in a rehabilitation programme. Setting: Outpatient pulmonary rehabilitation centre at a university hospital. Subjects: Thirty-two patients with moderate to severe chronic obstructive pulmonary disease. Intervention: All patients performed two endurance shuttle walking tests in random order. During endurance shuttle walking test I a mouthpiece was used in order to prevent spontaneous pursed lips breathing. During endurance shuttle walking test II spontaneous pursed lips breathing was used freely. Heart rate, oxygen saturation and the patients' estimated dyspnoea and leg fatigue on a Borg Category Ratio 10 scale were recorded before, directly after, and 5 and 10 minutes after the tests. Results: When spontaneous pursed lips breathing was used the patients walked on an average for 37 seconds (16%) longer (P