Table 1.

Open-circuit and rebreathing data at rest and exercise

	Rest	Exercise
Rectal temperature, °C
With mask and attachments	38.6±0.4	39.8±0.4
Without mask and attachments	38.6±0.5	39.5±0.5
Hematocrit, %	47.5±2.2	47.1±2.0
Ventilation, ml·min−1·kg−1	523±84	729±79
Tidal volume, ml/kg	5.5±0.6	5.2±0.7
O2 uptake, ml·min−1·kg−1	12.7±3.1	25.5±3.5
CO2 output, ml·min−1·kg−1	12.1±3.2	24.3±3.7
Respiratory exchange ratio	0.95±0.11	0.96±0.06
Respiratory rate, breaths/min	96±14	142±14
Rebreathing measurements
Mean alveolar Po2, Torr
Rebreathing 98% O2	556±28	544±13
Rebreathing 40% O2	114±28	93±8
End-inspiratory lung volume, ml/kg	24.4±4.9	40.7±6.7
End-expiratory lung volume, ml/kg	16.5±4.6	30.5±6.4
Pulmonary blood flow, ml·min−1·kg−1	127±45	239±50
DlCO, ml·min−1·Torr−1·kg−1
Rebreathing 98% O2	0.188±0.073	0.376±0.071
Rebreathing 40% O2	0.248±0.093	0.591±0.142
DlCO-std, ml·min−1·Torr−1·kg−1	0.290±0.108	0.553±0.105
DmCO, ml·min−1·Torr−1·kg−1
θCO of dog blood	0.614±0.313	1.105±0.392
θCO of human blood	0.606±0.315	1.084±0.380
Vc, ml/kg
θCO of dog blood	0.9±0.4	1.8±0.5
θCO of human blood	1.0±0.4	2.0±0.7
Septal volume, ml/kg	2.2±1.2	4.9±2.0

Values are means ± SD. Dl_CO, lung diffusing capacity for CO; Dm_CO, membrane diffusing capacity for CO; Dl_CO-std, Dl_CO standardized to hematocrit = 0.45 and alveolar Po₂ = 120 Torr; θ_CO, rate of CO uptake; Vc, pulmonary capillary blood volume.