Table 3– Constant load exercise data at 75% of the peak work rate in room air#
VariablesAirNormoxic heliox100% oxygen
Endurance time s394±35637±46670±43
Pa,O2 mmHg67±469±468±3540±14*,+533±23*,+
Pa,CO2 mmHg48±245±244±2*51±3*,+52±3.0*,+
Sa,O2 %89±291±2*91±2*99±1*,+99±1*,+
Borg dyspnoea scores7.4±2.05.7±1.8*6.7±1.54.9±1.0*6.3±1.3
Borg leg effort scores5.8±2.35.3±2.15.9±2.34.4±1.5*5.8±2.2
  • Data are presented as mean±sem for 12 subjects. Pa,O2: arterial oxygen tension; Pa,CO2: arterial carbon dioxide tension; Sa,O2: arterial oxygen saturation. #: peak work rate relates to the preliminary incremental test; : obtained on heliox and 100% oxygen at the same time as at exhaustion on room air. *: p<0.05 versus exhaustion in room air; +: p<0.05 versus normoxic heliox at the same time-point of exercise.