Assess The Difference Between Direct And Indirect Calorimeters

The Webster’s Dictionary defines calorimeter as, “an apparatus for measuring quantities of absorbed or emitted heat or for determining specific heats.” While direct calorimeters measure the amount of heat produced in a small chamber, indirect calorimeters measure the amount of heat produced by taking into account the amount of consumption of oxygen and elimination of carbon dioxide. Both contain the same concept, but have a different approach. Indirect calorimetry is the preferable way for physiologists to measure the amount of oxygen being consumed and carbon dioxide and nitrogen waste being produced, also known as gas exchange. These numbers can be used to estimate the level of energy that will be produced and exerted through exercise on a time interval. A chamber collects the gases and measures the volume. Although there is oxygen in the air for us to breathe in, there is only a certain amount our bodies can take in. Similarly, carbon dioxide is what we release, there is also a certain amount our bodies can let go of. Because there is actual oxygen uptake, indirect calorimetry is slightly more accurate than direct calorimetry because the heat calculation is more precise. Indirect calorimetry’s complications are, but
Arguably, it is also the less accurate way because the calorimeter is placed inside a chamber where heat is being transferred to water. Heat production is measured with a calorimeter while human bodies are exercising or at their resting point. The change in temperature of the water can estimate how many calories have been burned. Because the human body is 70% food energy and 30% efficient, ATP production is equal to the rate of change of heat produced in human bodies. Some believe that direct calorimetry is the more accurate way rather than indirect because the individual’s heat production is directly being measured. Although, it is a more costly way due to the equipment and its