Exercise retraining improves the prognosis and quality of life of patients with chronic lung or circulatory diseases. However, exercise intolerance may be caused by excessive ventilatory. Exposure to oxygen-replete air reduces this ventilatory overload, improves sleep and enhances responses to exercise. This study examine the impact of the acute manipulation of oxygen availability during inter-exercise recovery period of an intermittent cycling exercise on perceptual responses.

this randomized, controlled, study include adult patient with COPD. On separate days, 50 patients with COPD completed four sets of 4-min at 85% of VO2peak intercept by 3-min of passive recovery in two randomized between-sets recovery conditions. Rating exertion perception, gaz exchanges, heart rate, sleep quality and nocturnal heart rate variability were assessed.

Hypoxic exposure during inter-repetition recovery phases would reduce the ventilatory load during exercise. What's more, patients would not be forced to perform the sporting gesture in a restricted space or wearing a mask, limiting dyspnea and the perceived difficulty of the effort. Lastly, the induction of hypoxic stress during the re-training session helped to improve patients' sleep.

Inclusion Criteria:

• from 40 to 60 years
• follow-up in the pneumology unit of CHU Amiens - Picardie
• Chronic Obstructive Pulmonary Disease stade II
• Body mass index from 20 to 30 kg.m-2
• Tiffeneau index < 70% of predicted value
• FEV1 from 50 to 80% of predicted values
• Smoking cessation since at least 1 week
• Sedentary or physical active
• Affiliate to social security
• Written consent

Exclusion Criteria:

-