| Diagnosis | Gender | Mean age (years) | FEV1% predicted | FVC% predicted | FEV1/FVC ratio |
| Asthma (n = 60) | 19M/41F | 48.2 (15.4) | 80.6 (26.6) | 93.3 (26.7) | 71.6 (12.1) |
| COPD (n = 65) | 32M/33F | 67.9 (9.2) | 42.0 (30.5–56.5)* | 78.3 (21.3) | 40.2 (33.0–55.5)* |
| Interstitial lung disease (n = 41) | 24M/17F | 68.7 (9.9) | 72.0 (18.9) | 73.2 (20.2) | 78.1 (8.4) |
| Idiopathic hyperventilation (n = 36) | 8M/28F | 53.7 (15.2) | 93.0 (88.0–104.5)* | 99.3 (14.4) | 79.1 (7.6) |
| Healthy controls (n = 30) | 11M/19F | 53.8 (12.7) | 106.5 (16.0) | 113.3 (17.2) | 77.2 (6.3) |
Data are mean (SD) except for *median (interquartile range).
COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.