Aerosure and Six Minute Walk Distance in Severe COPD

Inclusion Criteria: * Stable severe COPD (FEV1 \< 50% predicted) * Modified MRC dyspnoea score 2 or greater * At least 10 pack year smoking history * Able to mobilise independently Exclusion Criteria: * Contraindications to spirometry \[1\] * Contraindications to clinical exercise testing \[2\] * Contraindications to HFAO (see section A.6.3b)) * Resting SpO2\>88% on air or on patient's usual oxygen prescription * Systolic arterial blood pressure (ABP) \>200mmHg, diastolic ABP \>100 mmHg 1. Cooper, B.G., An update on contraindications for lung function testing. Thorax, 2010. 2. ATS/ACCP Statement on Cardiopulmonary Exercise Testing. Am. J. Respir. Crit. Care Med., 2003. 167(2): p. 211-277.