THERMOREGULATION DURING EXERCISE IN HIGH HUMIDITY ENVIRONMENTS

Abstract

Thermoregulatory responses during one hour pedalling on bicycle ergometer were measured in a climatic chamber of 26°C at various humidity levels. Work intensities were 30, 40, 50, 60 and 70% of Vo₂max. Relative humidities were 30, 60 and 90%.
1) Oxygen intake remained nearly constant at the same work load and was not influenced by humidity level.
2) At work intensities of more than 60% of Vo₂max the elevation of rectal temperature was augmented by increased humidity.
3) The secretion of sweat increased, but the evaporation of sweat decreased with increased humidity, particularly at work intensities of 60% and 70% of Vo₂max.