Skip to main content

Table 2 Average ventilation, blood gases, blood lactate concentration, heart rate and perceived level of exertion during the 15-min hyperpnoea test in normoxia, hypoxia and hyperoxia

From: Effect of acute hypoxia on respiratory muscle fatigue in healthy humans

  Normoxia Hypoxia Hyperoxia
(l min-1) 159.3 (15.6) 158.1 (15.6) 159.5 (15.1)
fR (cycles·min-1) 54.2 (4.3) 54.2 (4.9) 53.7 (4.1)
VT (l) 2.95 (0.26) 2.93 (0.30) 2.98 (0.25)
Ti/Tt 0.48 (0.03) 0.49 (0.03) 0.49 (0.04)
PET CO2 (mmHg) 37.0 (2.1) 36.8 (1.7) 35.9 (2.3)
SpO2 (%) 98.4 (0.9) 79.3 (1.9) *** 98.9 (0.7)
PaO2 (mmHg) (n = 6) 123.7 (1.8) 46.0 (0.8) *** 347.9 (29.0) ###
PaCO2 (mmHg) (n = 6) 37.1 (1.2) 36.7 (1.1) 37.5 (0.8)
pH (n = 6) 7.42 (0.02) 7.42 (0.01) 7.40 (0.03)
[La] (mmol·l-1) (n = 6) 1.6 (0.4) 2.1 (0.7) + 1.3 (0.3)
HR (bpm) 98 (23) 99 (23) + 86 (16)
RPE (points) 6.0 (0.9) 5.8 (1.2) 5.2 (0.6)
  1. Values are means (SD). , minute ventilation; fR , breathing frequency; VT , tidal volume; Ti/Tt, ratio of inspiratory time to total respiratory cycle duration; PET CO2 , end-tidal CO2 partial pressure; SpO2 , arterial O2 saturation; PaO2 , arterial oxygen partial pressure; PaCO2 , arterial carbon dioxide partial pressure; [La], blood lactate concentration; HR, heart rate; RPE, rate of perceived exertion. *** significantly different from normoxia and hyperoxia (P < 0.001), ### significantly different from normoxia and hypoxia (P < 0.001), + significantly different from hyperoxia (P < 0.05)