| Subjects n | 82 |
| Sex male/female n/n | 34/48 |
| Age years | 65±7 |
| BMI kg·m−2 | 24.9±4.8 |
| Lung function | |
| FEV1 L | 1.0±0.4 |
| FEV1 % pred | 41±13 |
| FVC L | 2.4±0.8 |
| FVC % pred | 75±21 |
| FEV1/FVC | 0.45±0.10 |
| DLCO mmol·min−1·kPa−1 | 3.2±1.3 |
| DLCO % pred | 40±16 |
| RV L | 4.4±1.5 |
| RV % pred | 198±64 |
| RV/TLC % | 60.3±9.6 |
| RV/TLC % pred | 149±24 |
| Blood gases and pulse oximetry at sea level | |
| PaO2 kPa | 9.0±1.1 |
| PaCO2 kPa | 5.1±0.6 |
| SpO2 % | 93±3 |
| HAST blood gases and pulse oximetry | |
| PaO2 kPa | 6.3±0.6 |
| PaCO2 kPa | 4.9±0.6 |
| SpO2 % | 83±4 |
Data are presented as mean±sd, unless otherwise stated. BMI: body mass index; FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide; RV: residual volume; TLC: total lung capacity; PaO2: arterial oxygen tension; PaCO2: arterial carbon dioxide tension; SpO2: arterial oxygen saturation measured by pulse oximetry; HAST: hypoxia-altitude simulation test.