Table 2.
Subject characteristics
| Controls | COPD | P | |
|---|---|---|---|
| Subjects, n (female/male) | 12 (2f/10m) | 13 (3f/10m) | |
| Age, yr | 69 ± 2 | 66 ± 2 | 0.36 |
| BMI, kg/m2 | 26 ± 1 | 27 ± 2 | 0.73 |
| Lung function | |||
| FVC, liters | 4.8 ± 0.3 | 3.2 ± 0.2* | <0.001 |
| FEV1, liters | 3.5 ± 0.2 | 1.7 ± 0.2* | <0.001 |
| FEV1, %Predicted | 119 ± 6 | 55 ± 5* | <0.001 |
| FEV1/FVC, % | 79 ± 3 | 51 ± 4* | <0.001 |
| Resting SaO2, % | 95 ± 1 | 94 ± 1 | 0.57 |
| Physical activity and function | |||
| Knee extensor max, W | 29 ± 4 | 24 ± 4 | 0.38 |
| Knee extensor endurance, min | 14 ± 3 | 8 ± 1* | 0.04 |
| Gait speed, m/s | 1.38 ± 0.03 | 1.12 ± 0.08* | 0.007 |
| Steps per day | 5,387 ± 648 | 3,067 ± 250* | 0.004 |
| Sedentary physical activity, min/day | 1,245 ± 23 | 1,321 ± 15* | 0.01 |
| Light physical activity, min/day | 160 ± 16 | 111 ± 10 | 0.14 |
| Moderate-to-vigorous physical activity, min/day | 25 ± 4 | 8 ± 2* | 0.003 |
| Muscle characteristics | |||
| Quadriceps muscle mass, kg | 1.8 ± 0.1 | 1.4 ± 0.1 | 0.06 |
| Type 1 fibers, % | 40 ± 3 | 40 ± 5 | 0.61 |
| Type 2 fibers, % | 60 ± 3 | 60 ± 5 | 0.61 |
| NCAF | 2.7 ± 0.05 | 2.6 ± 0.05 | 0.78 |
| Medication history | |||
| Inhaled β-agonist/cholinergic antagonist, n | 0 | 7* | <0.001 |
| Corticosteroid, n | 0 | 0 | 1.00 |
| Statin-type drugs, n | 2 | 2 | 0.93 |
| Muscle relaxant, n | 0 | 2 | 0.14 |
Values are means ± SE.
COPD, chronic obstructive pulmonary disease; BMI, body mass index; FVC, forced vital capacity; FEV1, forced expiratory volume in 1 s; SaO2, arterial oxygen saturation; NCAF, number of capillaries around a fiber.
Medications listed are those taken over the past 6 mo.
*
Significant difference.