Age

50–75

Sex

ALL

Healthy volunteers

Accepted

COPD (FEV1/FVC \< 0.70 and FEV1 \< 0.80 predicted
Healthy subjects: no evidence of airways obstruction (FEV1/FVC \> 0.70 and FEV1 \> 0.80 predicted)
Smoking history \> 15 pack-years

Chronic hypoxemia and/or hypercapnia (PaO2 \< 60 mmHg or SpO2 \< 88% at rest and/or PaCO2 \> 45 mmHg)
Recent exacerbation (\< 3 months)
Recent cancer (\< 3 years)
Diabetes
Myopathy, neuromuscular or articular disease
Unstable cardiac disease
Absolute contraindications to exercise testing
Regular physical activity or exercise training program in the last 2 months
Physical activity score \> 9 in the Voorips questionnaire
Thigh skinfold thickness \> 15 mm
BMI \> 30

Muscle Metabolism and Oxygenation During Localized Fatigue-exercise in COPD