Human Calorimetry

Abstract

The heat production, heat eliminationand the rectal and surface temperature changes of ten adult subjects have been studied in the respiration calorimeterin basal condition and after the ingestion of carbohydrate and protein meals. On the averageheat elimination exceeds heat production by 13 per cent in the first basal hour and 9 per cent in the second. The body first falls in temperature uniformly; laterthe surface falls much more than the rectal temperature, indicating a heat regulating adjustment. After the meal heat is first stored in the body by general rise of temperaturebut later the surface temperature rises much more than the rectal temperature (about 1°C. compared to 0.25°C.), radiation from the body is increased and the extra heat is eliminated. Increased evaporation plays a minor role. The rise of surface temperature is most marked on the legbut the use of the ‘thermal circulation index’ shows the increased circulation is general. It commences 20 minutes after the ingestion. The effects of protein and of solid and liquid carbohydrate are similar. They are closely correlated with an increase pulse rate after the meal. There is no evidence of a withdrawal of blood from the somatic tissues to the visceral, but a definite general increase in circulationwhich may well be due to the same factors as cause the specific dynamic action.