What is heat gain and heat loss?

In order to maintain a constant body temperature, we must balance heat production with heat loss.

• If we are getting too cold, we must reduce heat loss whilst increasing heat production by increasing our level of activity or metabolism

• If we get too hot the reverse must occur – decrease heat production by decreasing metabolism and increasing heat loss

Heat gain must be equal to heat loss.

The inputs and outputs of heat are as follows;

Heat inputs

• Heat from body processes (metabolism), in particular respiration of the liver and muscle cells

• Heat gained from surroundings by conduction and radiation

Heat outputs

• Radiation, conduction and convection to surroundings

• Evaporation of water from skin and lungs; warm air breathed out, warm urine and faeces