Overall results for ambient air versus hyperoxia – end-exercise and isotime
| Ambient air end-exercise mean | Hyperoxia | ||||
| End-exercise | Isotime | ||||
| Mean | Difference (95% CI) | Mean | Difference (95% CI) | ||
| IET overall | |||||
| Work rate W | 155.4 | 167.8 | 12.4 (9.1–15.6)*** | NA | NA |
| SpO2 % | 92.0 | 96.0 | 4.0 (3.2–5.4)*** | 97.0 | 4.0 (3.4–5.6)*** |
| V′E L·min−1 | 70.7 | 71.7 | 1.0 (−2.2–4.3) | 39.2 | −5.9 (−8.8– −3.1)*** |
| Heart rate bpm | 141.0 | 142.0 | 1.2 (−3.0–5.3) | 118.0 | −4 (−6.3– −1.6)*** |
| V′E/V′CO2 | 35.9 | 32.6 | −3.3 (−4.6– −2.0)*** | 33.9 | −3.6 (−4.3– −3.0)*** |
| Arterial lactate mmol·L−1 | 5.0 | 5.14 | 0.14 (−0.5–0.2) | NA | NA |
| PaCO2 kPa | 5.0 | 5.5 | 0.5 (0.3–0.7)*** | NA | NA |
| PaO2 kPa | 9.6 | 30.9 | 21.3 (19.1–23.4)*** | NA | NA |
| SaO2 % | 92.3 | 99.4 | 7.1 (5.4–8.9)*** | NA | NA |
| Borg CR10 dyspnoea score | 6.0 | 5.4 | −0.6 (−0.2– −0.9)*** | NA | NA |
| Borg CR10 leg score | 5.4 | 5.7 | 0.3 (−0.7–0.2) | NA | NA |
| CWRET overall | |||||
| Endurance time minutes:seconds | 10:43 | 16:56 | 6.13 (4:59–7:35)*** | NA | NA |
| SpO2 % | 91.0 | 97.0 | 6.0 (4.3–6.9)*** | 96.0 | 5.0 (3.4–5.8)*** |
| V′E L·min−1 | 66.0 | 61.0 | −5.0 (−2.0– −8.0)*** | 54.7 | −8.3 (−11.2– −5.4)*** |
| Heart rate bpm | 145.0 | 144.0 | −1.0 (−3.3–1.3) | 135.0 | −6.0 (−7.2– −3.9)*** |
| V′E/V′CO2 | 37.0 | 34.0 | −3.0 (−2.2– −4.1) | 31.9 | −4.9 (−5.8– −4.1)*** |
| Arterial lactate mmol·L−1 | 6.2 | 4.7 | −1.5 (−2.2– −0.8)*** | NA | NA |
| PaCO2 kPa | 5.0 | 5.3 | 0.3 (0.2–0.5)*** | NA | NA |
| PaO2 kPa | 13.9 | 32.1 | 18.2 (15–21.5)*** | NA | NA |
| SaO2 % | 90.1 | 99.7 | 9.6 (7.3–12)*** | NA | NA |
| Borg CR10 dyspnoea score | 6.0 | 5.1 | −0.9 (−0.5– −1.3)*** | NA | NA |
| Borg CR10 leg score | 5.5 | 5.1 | −0.4 (−0.8– −0.1)* | NA | NA |
Data are presented as mean and mean differences with 95% confidence intervals (lower limit–upper limit). IET: incremental exercise test; CWRET: constant work-rate exercise test; NA: not available; SpO2: oxygenation by pulse oximetry; V′E : minute ventilation; bpm: beats per min; V′E/V′CO2: ventilatory equivalent for CO2: PaCO2, PaO2: arterial tension for CO2 and O2; SaO2: arterial oxygen saturation. *: p=0.05; ***: p<0.001.