Control | COPD | ||
Without hypoxaemia | With hypoxaemia | ||
Participants n | 11 | 16 | 11 |
Age years | 70.5±2.4 | 72.9±1.7 | 71.2±2.1 |
Males n | 11 | 16 | 10 |
Smoking status n | |||
Current smoker | 0 | 3 | 3 |
Past smoker | 7 | 13 | 8 |
Never-smoker | 4 | 0 | 0 |
Smoking history pack-years | 10.5±4.8 | 72.7±14.1* | 70.5±14.4* |
BMI kg·m−2 | 23.1±0.5 | 21.6±0.9 | 19.7±2.2 |
FEV1/FVC | 81.7±2.1 | 47.8±5.0* | 41.2±3.5* |
FEV1 L | 2.55±0.11 | 1.43±0.17* | 1.06±0.14* |
FEV1 % pred | 91.7±3.4 | 54.7±5.5* | 42.1±6.0* |
FVC L | 3.14±0.14 | 2.99±0.21 | 2.59±0.23 |
FVC % pred | 90.5±3.2 | 84.7±7.4 | 80.6±6.6 |
COPD stage | |||
I | 2 | 1 | |
II | 8 | 1 | |
III | 4 | 6 | |
IV | 2 | 3 | |
Duration of COPD years | 3.81±1.38 | 4.72±1.09 | |
Peak work rate W | 93.2±8.4 | 59.4±4.6* | 72.3±7.0 |
PaO2 mmHg | 79.0±3.4 | 67.7±2.1** | |
PaCO2 mmHg | 40.0±2.2 | 40.5±1.8 | |
SpO2 % at rest | 97.4±0.4 | 96.1±0.4 | 94.8±0.5* |
Data are presented as mean±sem, unless otherwise stated. BMI: body mass index; COPD: chronic obstructive pulmonary disease; hypoxaemia: exertional hypoxaemia; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; % pred: % predicted; peak work rate: maximal incremental cycle work rate; PaO2: arterial oxygen tension; PaCO2: arterial carbon dioxide tension; SpO2: arterial oxygen saturation measured by pulse oximetry. *: p<0.05 versus control; **: p<0.05 versus COPD without hypoxaemia.