Calorimetry is the measurement of the amount emitted or absorbed heat. In biology and medicine calorimetry are used to study thermal effects accompanying the processes of metabolism (see Metabolism and energy) or the various activities of organs of the entire organism. For a unit of measure accept Joule, calorie (see "Units") or kcal equal to 1000 calories. Instruments, which are measured thermal effects are called calorimeters.
In calorimeters with constant temperature thermal effect is measured by the change in the physical state of the substance (for example, ice - water); in calorimeters with variable temperature is registered change of temperature calorimetric liquid. There are also differential calorimeters: in one half of such calorimeter is the study of the thermal reaction, and in another you enter the same amount of heat to the temperature difference between both systems is zero. The heat can also be explored by indirect calorimetry, limited to the study of pulmonary gas exchange and accounting substances secreted by the kidneys, intestines and skin. Precisely enough energy consumption can be calculated and the study of one of the gas exchange (see).