The Heat Production of the Fasting Rat in Relation to the Environmental Temperature

Abstract

The heat production of the albino rat in the postabsorptive state was determined in 122 8-hour periods of measurement at environmental temperatures ranging from 7.5° to 35.0°C. The critical temperature for the fasting rat was found to be 30°C. The metabolism was constant over a range of temperatures extending from 30°C. to 33°C. The percentage of the total heat eliminated as latent heat of water vapor increased steadily from 7.9% to 59.2%, with rise in environmental temperature from 7.5°C. to 35°C., though the absolute amount of heat eliminated in this manner was practically constant up to 31°C., above which a definite increase took place.