Symptom limited peak of constant load cycle exercise at 75% Wmax (57 (6) W, 39 (2)% of predicted maximum)
| Variable | RA + PL | RA + BD | O2 + PL | O2 + BD | p value (ANOVA) |
|---|---|---|---|---|---|
| Values are mean (SE). | |||||
| *p<0.05 v RA+PL; †p<0.05 v RA+BD; ‡p<0.05 v O2+PL. | |||||
| RA, room air; BD, bronchodilator; PL, placebo; O2, oxygen; V̇co2, carbon dioxide output; V̇e, minute ventilation; F, breathing frequency; Ti, Te, inspiratory and expiratory time; Vt, total volume; IC, inspiratory capacity; Sao2, arterial saturation; IRV, inspiratory reserve volume; EELV, end expiratory lung volume; EILV, end inspiratory lung volume; TLC, total lung capacity; Paco2, arterial carbon dioxide tension; HCO3−, bicarbonate. | |||||
| Endurance time (min) | 5.4 (0.9) | 7.1 (1.3) | 8.5 (1.4)* | 10.4 (1.6)*†‡ | 0.002 |
| Dyspnoea (Borg) | 6.4 (0.5) | 5.8 (0.6) | 5.4 (0.6) | 5.3 (0.5) | 0.095 |
| Leg discomfort (Borg) | 4.9 (0.5) | 5.4 (0.5) | 5.2 (0.5) | 5.9 (0.5) | 0.069 |
| Heart rate (beats/min) | 122 (5) | 124 (4) | 121 (5) | 124 (5) | 0.239 |
| Sao2 (%) | 92 (1) | 93 (1) | 97 (0)*† | 97 (1)*† | <0.0005 |
| V̇co2 (l/min) | 1.15 (0.11) | 1.26 (0.12)* | 1.21 (0.12) | 1.30 (0.14)* | 0.071 |
| V̇e (l/min) | 38.6 (2.9) | 44.3 (3.5)* | 37.2 (2.7)† | 41.5 (3.5)*†‡ | <0.0005 |
| V̇e/V̇co2 | 35.5 (1.6) | 36.9 (1.6)* | 32.4 (1.3)*† | 33.5 (1.5)† | <0.0005 |
| F (breaths/min) | 34 (2) | 36 (2) | 33 (2) | 34 (2) | 0.063 |
| Te (s) | 1.08 (0.05) | 1.06 (0.06) | 1.12 (0.06) | 1.10 (0.06) | 0.202 |
| Ti (s) | 0.73 (0.04) | 0.71 (0.04) | 0.75 (0.04) | 0.74 (0.05) | 0.526 |
| Vt (l) | 1.16 (0.09) | 1.28 (0.10)* | 1.14 (0.08)† | 1.26 (0.10)*‡ | <0.0005 |
| IC (l) | 1.50 (0.12) | 1.67 (0.13)* | 1.48 (0.10)† | 1.68 (0.13)*‡ | <0.0005 |
| IRV (l) | 0.34 (0.05) | 0.37 (0.06) | 0.34 (0.04) | 0.42 (0.05) | 0.335 |
| EELV (l) | 5.17 (0.22) | 4.91 (0.24)* | 5.30 (0.23)† | 4.90 (0.21)*‡ | <0.0005 |
| EILV/TLC (%) | 95 (1) | 94 (1) | 95 (1) | 94 (1) | 0.227 |
| Paco2 (mm Hg) | 41.4 (1.2) | 40.2 (1.7) | 45.7 (1.4)*† | 43.5 (2.0)*‡ | 0.012 |
| HCO3− (mmol/l) | 22.5 (0.5) | 22.0 (0.5) | 23.5 (0.7)*† | 22.6 (0.5) | 0.028 |
| Base excess (mmol/l) | −2.4 (0.5) | −2.7 (0.5) | −2.3 (0.8) | −2.8 (0.5) | 0.342 |
| pH | 7.36 (0.01) | 7.36 (0.01) | 7.33 (0.01) | 7.34 (0.01) | 0.713 |