Table 2.
Peak and submaximal exercise data
| Control | COPD | P Value | |
|---|---|---|---|
| Peak exercise | |||
| Workload, W | 173 ± 50 | 96 ± 21* | <0.01 |
| V̇o2, mL·kg−1·min−1 | 27.1 ± 5.5 | 16.9 ± 4.1* | <0.01 |
| V̇o2, L/min | 2.3 ± 0.5 | 1.6 ± 0.3* | <0.01 |
| V̇co2, L/min | 2.6 ± 0.7 | 1.7 ± 0.5* | <0.01 |
| RER | 1.15 ± 0.08 | 1.04 ± 0.09* | 0.01 |
| Heart rate, beats/min | 157 ± 17 | 125 ± 24* | <0.01 |
| VE, L/min | 93 ± 24 | 54 ± 20* | <0.01 |
| fB, breaths/min | 37 ± 4 | 33 ± 8 | 0.12 |
| VT, L | 2.5 ± 0.8 | 1.6 ± 0.3* | <0.01 |
| VE/V̇co2 | 35 ± 4 | 33 ± 6 | 0.62 |
| VE/V̇o2 | 40 ± 5 | 35 ± 7 | 0.06 |
| Submaximal exercise | |||
| Workload, W | 62 ± 14 | 45 ± 10* | <0.01 |
| V̇o2, mL·kg−1·min−1 | 15.4 ± 2.3 | 13.4 ± 2.8 | 0.08 |
| V̇o2, L/min | 1.3 ± 0.2 | 1.3 ± 0.1 | 0.81 |
| VCO2, L/min | 1.2 ± 0.2 | 1.2 ± 0.1 | 0.63 |
| RER | 0.90 ± 0.04 | 0.93 ± 0.07 | 0.25 |
| Heart rate, beats/min | 102 ± 8 | 103 ± 10 | 0.66 |
| VE, L/min | 33 ± 4 | 37 ± 6 | 0.11 |
| fB, breaths/min | 23 ± 4 | 27 ± 5* | 0.04 |
| VT, L | 1.5 ± 0.3 | 1.4 ± 0.2 | 0.37 |
| IC, L | 3.7 ± 0.9 | 2.5 ± 0.5* | <0.01 |
| IC/TLC, % | 55 ± 7 | 36 ± 10* | <0.01 |
| EILV/TLC, % | 67 ± 8 | 85 ± 7* | <0.01 |
| Peak Pes,ins, cmH2O | −10 ± 3 | −19 ± 6* | <0.01 |
| Peak Pes,exp, cmH2O | 8 ± 7 | 19 ± 7* | <0.01 |
| Pes,inspTI, cmH2O·s | −7 ± 2 | −11 ± 2* | <0.01 |
| Pes,expTI, cmH2O·s | 4 ± 2 | 14 ± 7* | <0.01 |
| SaO2, % | 97 ± 1 | 96 ± 1* | <0.01 |
| RPE | 11 ± 2 | 14 ± 3* | 0.03 |
| Dyspnea | 2 ± 1 | 4 ± 2* | <0.01 |
| MAP, mmHg | 101 ± 8 | 107 ± 15 | 0.40 |
| SVR, mmHg·L−1·min−1 | 8.3 ± 1.3 | 9.9 ± 1.9* | 0.04 |
Mean ± SD. Data from 23 participants (CTL = 10; COPD = 13). Submaximal exercise data were averaged during min 5–8 of the submaximal exercise test. COPD, chronic obstructive pulmonary disease; V̇o2, oxygen uptake; V̇co2, carbon dioxide production; RER, respiratory exchange ratio; VE, ventilation; fB, breathing frequency; VT, tidal volume; IC, inspiratory capacity; TLC, total lung capacity; EILV, end inspiratory lung volume; Pes,ins, inspiratory esophageal pressure; Pes,exp, expiratory esophageal pressure; TI, time integral; RPE, rating of percieved exertion; MAP, mean arterial pressure; SVR, systemic vascular resistance.
*
Significantly different from control.