Table 1. Main characteristics of subjects.
| Healthy controls | COPD | COPDND | COPDD | |
| N (M/F) | 15 (9/6) | 28 (16/12) | 15 (9/6) | 13 (7/6) |
| Age, y | 65±6 | 65±7 | 66±7 | 65±6 |
| Height, cm | 170±11 | 169±9 | 168±7 | 169±11 |
| Weight, kg | 72±12 | 71±10 | 74±10 | 67±10 |
| BMI, kg/m | 24.9±3.3 | 25.1±2.8 | 26.4±2.5 | 23.5±2.3# |
| FFMI, kg/m | 18.0±1.9 | 17.5±1.8 | 18.0±2.0 | 16.9±1.5 |
| Smoking status current/former/never | 1/7/7 | 10/18/0** | 7/8/0** | 3/10/0* |
| FEV1, % predicted | 113±15 | 59±16*** | 61±13*** | 56±19*** |
| FVC, % predicted | 120±17 | 104±22* | 98±20* | 110±24 |
| D L,CO, % predicted | 95±19 | 51±16*** | 55±16*** | 47±16*** |
| S p,o 2 at rest, % | 98 (98, 100) | 96 (95, 97)*** | 97 (96, 97)*** | 95 (94, 98)*** |
| P a,o 2 at rest, kPa | 12.1±1.1 | 9.3±1.0*** | 9.5±0.8*** | 9.1±1.2*** |
| P a,co 2 at rest, kPa | 5.3±0.2 | 5.2±0.5 | 5.1±0.5 | 5.2±0.4 |
| Daily physical activity, counts/min | 328 (276, 489) | 214 (129, 300)** | 208 (140, 278)** | 220 (108, 366) |
Values are expressed as mean±SD or median (25th percentile, 75th percentile). Abbreviations: BMI, body mass index; FFMI, fat-free mass index; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; D L,CO, diffusion capacity of the lungs for carbon monoxide; Sp,o 2, oxygen saturation measured via pulse oximetry. Significance of difference compared to controls: *p<0.05, **p<0.01, ***p≤0.001. Level of significance COPDD vs. COPDND patients: #p<0.05.