| Summiters without oxygen | p-value (versus sea level) | Other climbers | p-value (versus sea level) | p-value (between groups) |
Subjects n | 5 | | 6 | | |
Spontaneous breathing | | | | | |
Resp. rate (pneumotach.) breaths·min-1 | 10.7±4.3 | ns | 20.2±1.9 | <0.0025 | <0.001 |
Resp. rate (inductive belt) breaths·min−1 | 10.8±5.9 | ns | 18.7±4.3 | <0.002 | <0.05 |
VT mL | 1391±505 | ns | 973±134 | ns | ns |
V′E L·min−1 | 13.3±1.8 | <0.01 | 19.2±1.5 | <0.0005 | <0.0002 |
PET,CO2 mmHg | 28.2±1.4 | <0.0001 | 24.2±2.4 | <0.001 | <0.01 |
Sa,O2 % | 87.3±1.8 | <0.0005 | 88.7±2.3 | <0.0001 | ns |
VT/BSA mL·m−2 | 750±252 | ns | 511±52 | ns | <0.05 |
V′E /BSA L·min−1·m−2 | 7.21±0.78 | <0.01 | 10.13±0.74 | <0.001 | <0.0001 |
6 breaths·min−1 controlled breathing | | | | | |
Resp. rate breaths·min−1 | 6.0±0.5 | ns | 6.2±0.7 | ns | ns |
VT mL | 2383±247 | <0.025 | 2428±1060 | ns | ns |
V′E L·min−1 | 14.4±1.4 | <0.025 | 15.1±0.62 | ns | ns |
PET,CO2 mmHg | 28.1±2.4 | <0.005 | 26.6±2.7 | <0.01 | ns |
Sa,O2 % | 88.4±1.9 | <0.0005 | 87.9±1.5 | <0.0001 | ns |
VT/BSA mL·m−2 | 1291±111 | <0.025 | 1285±582 | ns | ns |
V′E /BSA L·min−1·m−2 | 7.81±0.62 | <0.025 | 8.01±3.44 | ns | ns |
Maximal parameters | | | | | |
MVV L·min−1 | 191.4±35.5 | ns | 183.0±17.3 | ns | ns |
VC mL | 5258±581 | ns | 5494±367 | ns | ns |
MVV/BSA L·min−1·m−2 | 103.4±15.0 | ns | 96.3±4.7 | ns | ns |
VC/BSA mL·m−2 | 2847±229 | ns | 2897±166 | ns | ns |
Ventilatory control | | | | | |
HVR L·min−1/% Sa,O2 | −2.14±1.13 | <0.025 | −5.09±2.53 | <0.025 | <0.05 |
Ventilatory efficiency | | | | | |
Sa,O2/V′E (sp. br.) %/L·min−1 | 6.66±0.86 | <0.005 | 4.64±0.32 | <0.025 | <0.0005 |
Sa,O2/V′E (6 breaths·min−1) %/L·min−1 | 6.19±0.66 | <0.025 | 6.64±2.51 | ns | ns |
VD/VT sp. br. | 0.092±0.035 | ns | 0.162±0.047 | ns | <0.025 |
VD/VT 6 breaths.min−1 | 0.062±0.078 | ns | 0.047±0.084 | ns | ns |
Ventilatory reserve | | | | | |
100×(MVV–V′E(Sa,O2 = 70))/MVV % | 66.6±14.2 | ns | 26.7±21.3 | <0.002 | <0.01 |
MVV– V′E(Sa,O2 = 70) L·min−1 | 129.3±44.2 | ns | 47.6±38.9 | <0.01 | <0.01 |
Cardiovascular parameters | | | | | |
Heart rate beats·min−1 | 72.9±9.5 | ns | 72.6±11.3 | <0.05 | ns |
Systolic blood pressure mmHg | 127.2±16.2 | ns | 130.3±9.6 | ns | ns |
Diastolic blood pressure mmHg | 85.4±11.9 | <0.05 | 90.4±8.3 | <0.01 | ns |