Table 1.
Constant load exercise data at 75% WRpeak
| Variables | Normoxia | Normoxic helium | 100% oxygen |
| Endurance time s | 390 | 640 | 670 |
| tlim | Isotime | Isotime | |
| V′E L·min−1 | 43.7 | 48.6 | 37.4 |
| VT L | 1.68 | 1.87 | 1.56 |
| Breathing frequency breaths·min−1 | 26 | 26 | 24 |
| tI s | 0.69 | 0.99 | 0.98 |
| tI/ttot % | 34 | 43 | 46 |
| ΔIC L | −0.232 | 0.080 | −0.090 |
| VT/IC ratio | 0.76 | 0.74 | 0.66 |
| SaO2 % | 87 | 91 | 99 |
| Borg dyspnoea score | 8 | 5 | 5 |
| Borg leg fatigue score | 6 | 5 | 4 |
Isotime data are those obtained on normoxic heliox and 100% oxygen at the same time as at the limit of tolerance (tlim) on room air. WRpeak: peak work rate at the preliminary incremental test in room air; V′E: minute ventilation; VT: tidal volume; tI: inspiratory time; tI/ttot: duty cycle of inspiration; ΔIC: change in IC from baseline; SaO2: arterial oxygen saturation.