Direct measurements of energy metabolism at altitudes above 5,500 m are very scarce. On a group of 12 elite climbers (11 males, 1 female; age 36.1 ± 6.4 [x ± SD] yr; sea level VO2max 3.62 ± 0.43 L/min), members of the 1997 Italian expedition to Mt. Lhotse, the following measurements were performed in a tent-laboratory situated at 7,600 m (barometric pressure 305 Torr), at rest and during exhausting step exercise (30 cm bench, 8 cpm): pulmonary ventilation (VE), end-tidal pressures of O2 (PETO2) and CO2 (PETCO2), O2 uptake (VO2), heart rate (HR), arterialized earlobe blood pulse oximetry (SaO2) and lactate concentration ([La]b). The following results were obtained: 1) at rest, VE 23.4 ± 0.6 L/min, PETO2 37 ± 2 Torr, PETCO2 21 ± 5 Torr, VO2 0.31 ± 0.07 L/min, HR 88 ± 11 b/min; SaO2 66 ± 7%, [La]b 2.1 ± 0.6 mM; 2) during exhausting exercise, VE 48.8 ± 6.1 L/min, PETO2 38 ± 2 Torr, PETCO2 20 ± 4 Torr, VO2 0.73 ± 0.08 L/min, HR 112 ± 16 b/min, SaO2 63 ± 12%, [La]b 2.0 ± 0.6 mM. At 7,600 m VO2 during the exhausting exercise was about 20% of sea level VO2max, corresponding to the energy expenditure necessary to walk on the ground, at sea level, at about 3-4 km/h. At 7,660 m no lactate accumulation in blood is observed, at voluntary exhaustion, above that already present at rest.

Energy metabolism at 7,600 M

POGLIAGHI, Silvia;
1998-01-01

Abstract

Direct measurements of energy metabolism at altitudes above 5,500 m are very scarce. On a group of 12 elite climbers (11 males, 1 female; age 36.1 ± 6.4 [x ± SD] yr; sea level VO2max 3.62 ± 0.43 L/min), members of the 1997 Italian expedition to Mt. Lhotse, the following measurements were performed in a tent-laboratory situated at 7,600 m (barometric pressure 305 Torr), at rest and during exhausting step exercise (30 cm bench, 8 cpm): pulmonary ventilation (VE), end-tidal pressures of O2 (PETO2) and CO2 (PETCO2), O2 uptake (VO2), heart rate (HR), arterialized earlobe blood pulse oximetry (SaO2) and lactate concentration ([La]b). The following results were obtained: 1) at rest, VE 23.4 ± 0.6 L/min, PETO2 37 ± 2 Torr, PETCO2 21 ± 5 Torr, VO2 0.31 ± 0.07 L/min, HR 88 ± 11 b/min; SaO2 66 ± 7%, [La]b 2.1 ± 0.6 mM; 2) during exhausting exercise, VE 48.8 ± 6.1 L/min, PETO2 38 ± 2 Torr, PETCO2 20 ± 4 Torr, VO2 0.73 ± 0.08 L/min, HR 112 ± 16 b/min, SaO2 63 ± 12%, [La]b 2.0 ± 0.6 mM. At 7,600 m VO2 during the exhausting exercise was about 20% of sea level VO2max, corresponding to the energy expenditure necessary to walk on the ground, at sea level, at about 3-4 km/h. At 7,660 m no lactate accumulation in blood is observed, at voluntary exhaustion, above that already present at rest.
1998
hypoxia; aerobic metabolism; functional evaluation
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/641552
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