Substrate utilization during prolonged exercise with ingestion of 13C-glucose in acute hypobaric hypoxia (4,300 m)

摘要: Energy substrate oxidation was measured using indirect respiratory calorimetry combined with tracer technique in five healthy young male subjects, during a 80-min exercise period on ergocycle ingestion of 140 g 13C-labelled glucose, normoxia and acute hypobaric hypoxia (445 mmHg or 4,300 m), at the same relative \( {\left( {77\% \dot{V}_{{{\text{O}}_{2} \max }} } \right)} \) absolute workload (161±8 W, corresponding to 77 54% \dot{V}_{{{\text{O}}_{{\text{2}}} {\text{max}}}} normoxia). The rate exogenous glucose not significantly different three experimental situations: 21.4±2.9, 20.2±1.2 17.2±0.6 over last 40 min ~77 ~54% hypoxia, respectively, providing 12.5±1.5, 16.8±1.1 14.9±1.1% energy yield, although resulted higher plasma concentration than normoxia. contribution carbohydrate (CHO) yield (92.0±2.1%) for both given (75.3±5.2%) (78.1±1.8%). This greater reliance CHO entirely due larger endogenous yield: 75.9±1.7% versus 66.6±3.3 55.2±3.7% workload.