Effect of body temperature on steady state ventilation and metabolism in exercise.

Abstract

AbstractPetersen, E. S. and H. Vejby‐Christensen. Effect of body temperature on steady state ventilation and metabolism in exercise. Acta physiol. scand. 1073. 89. 342–351.Four healthy subjects were studied at rest and during steady slate of work at normal room and body temperature, and at elevated body temperature (38.5o C) in a climatic chamber. Ventilation, oxygen uptake, carbon dioxide elimination, heart rate, and blood lactate and pyruvate concentrations were measured. At equal work loads ventilation was not different, although respiratory rate was consistently higher and tidal volume lower at elevated temperature. Oxygen uptake was lower, and the ventilatory equivalent therefore higher in hyperthermia than in normothermia. Blood lactate concentration was higher both at rest and at all work loads indicating an increased anaerobic energy yield in hyperthermia. The study indicates the existence of a temperature threshold near 38o C, above which a relative hyperventilation is seen. The observed hyperventilation is hardly caused by changes in the [H+]‐stimulus, and it is suggested that hyperthermia per se or through interaction with other stimuli might constitute the additional ventilatory drive.