The influence of intravenous glucose on body temperature

The influence of an intravenous infusion of glucose (500 ml of 20% w/v), on heat production and variables which contribute to heat loss was studied in six normal human volunteers. Mannitol (500 ml of 20% w/v) was infused on a different occasion as an osmotic control. Both infusions produced changes in haematocrit and osmolality of a similar magnitude. Heat production increased by 20% after intravenous glucose but only a small increase in heat production was observed after intravenous mannitol. Calf blood flow increased after both infusions but hand blood flow increased only after the glucose infusions. The increase in skin temperature which was observed after both infusions was associated with increases in peripheral blood flow. Core temperature decreased slightly following administration of both substances. The changes in metabolic heat production and cardiovascular function are discussed. These changes do not appear to be due to the catecholamine response to hyperglycaemia and hyperosmolality.