Respiratory Quotient for Carbohydrates

When estimating basal metabolic rate (BMR) from carbon dioxide production, the respiratory quotient (RQ or respiratory coefficient) is a dimensionless Quantity. The ratio of carbon dioxide produced by the body to oxygen consumed by the body is used to calculate it. Such measurement, like oxygen uptake measurement, are example of indirect calorimetry. A Respirometer is used to measure it. Because various energy pathways are used for lipids, carbs, and proteins, the respiratory quotient value reveals which macronutrients are being digested. The respiratory quotient for lipid metabolism is roughly 0.7, for proteins it is approximately 0.8, and for carbs it is approximately 1.0.  Most of the time, however, energy consumption is composed of both fats and carbohydrates.

Respiratory Quotient 

When estimating basal metabolic rate (BMR) from carbon dioxide production, the respiratory quotient (or RQ or respiratory coefficient) is a unit-less Quantity. Such measurement, like oxygen uptake measurement, are example of indirect calorimetry. Ganong Respirometer is used to measure it.

Calculation

The respiratory quotient (RQ) is determined by the following ratio:

RQ= CO₂produced/O₂consumed

CO₂  and O₂ must be given in the same units and in quantities proportional to the number of molecules in this computation. Moles or quantities of gas at standard temperature and pressure would be acceptable inputs time units may be included, but they cancel out since they must be the same in numerator and denominator.

For species in metabolic balance, respiratory coefficients typically range from 1.0 (indicating the value expected for pure carbohydrate oxidation) to 0.7. (The value expected for pure fat oxidation). For further information on how these figures are calculated, see BMR. An average value between these amounts results from a mixed fat and carbohydrate diet. An organism burning glucose to make or “laid down” fat may have an RQ greater than 1.0. (for example, a bear preparing for hibernation).

For each liters (L) of CO₂ produced, the RQ value equates to a caloric value. If data on O₂ consumption is available, it is frequently used directly because it is a more direct and dependable measure of energy generation.

The energy produced by protein contributes to RQ in the sense that it is measured. However, no one RQ can be allocated to the oxidation of protein in the diet due to the intricacy of the multiple methods in which different amino acids can be oxidised.

Applications

The respiratory quotient has practical uses in severe cases of chronic obstructive pulmonary disease, where patients expend a lot of energy on respiratory effort. The respiratory quotient is driven down by increasing the quantity of fats in the diet, resulting in a proportionate decrease in the amount of CO₂ generated. This minimises the amount of energy required on breathing by lowering the respiratory load to remove CO₂.

The Respiratory Quotient can be used to determine if a person is overfeeding or underfeeding. Underfeeding lowers the respiratory quotient by forcing the body to consume fat stores, whereas overfeeding raises it by causing lipogenesis.  A respiratory quotient of less than0.85 implies underfeeding, Whereas a respiratory quotient of more than 1.0 indicates overfeeding. This is especially critical in patients with limited respiratory systems, because an elevated respiratory quotient correlates with higher respiratory rate and lower tidal volume, putting affected patients at danger.

The respiratory quotient can be used to assess liver function and diagnose liver illness because of its role in metabolism. Non-protein respiratory quotient (npRQ) values are good indications in the prediction of overall survival rate in patients with liver cirrhosis. Patients with a npRQ<0.85. had a worse survival rate than those with a npRQ>0.85. A reduction in npRQ indicates that the liver is storing less glycogen. According to previous studies, non-alcoholic fatty liver disease is associated with a low respiratory quotient value, and the non protein respiratory quotient value was a good predictor of disease severity.

Aquatic scientists have recently employed the respiratory quotient to provide light on its environmental applications. RQ appears to be linked to the elemental composition of the respired compounds, according to experiments with natural bacterioplankton utilising various single substrates. Bacterioplankton RQ is thus proved to be not only a useful feature of determining bacterioplankton respiration, but also an important ecosystem state variable that provides unique information about aquatic ecosystem functioning.  According to the stoichiometry of the many metabolised substrates, dissolved oxygen (O₂) and carbon dioxide (CO₂) in aquatic ecosystems should covary inversely due to photosynthesis and respiration Processing. We could learn more about metabolic behaviour and the combined roles of chemical and physical forces in shaping the biogeochemistry of aquatic ecosystems by using this quotient.

Respiratory Quotient value for Carbohydrates

The respiratory quotient (RQ) is a measure of the basal metabolic rate and is the ratio of carbon dioxide generated to oxygen Absorbed.

The RQ value of carbohydrates is 1.0.

RQ of fats is 0.7.

RQ of proteins is 0.8.

Conclusion

The respiratory quotient (RQ or respiratory coefficient) is a dimensionless number used to calculate basal metabolic rate (BMR) from carbon dioxide production. It is calculated using the ratio of carbon dioxide produced by the body to oxygen consumed by the body. Indirect calorimetry is a term that refers to measurements like oxygen uptake. It is measured with a respirometer. The respiratory quotient value tells which macronutrients are digested because different energy routes are employed for lipids, carbohydrates, and proteins.

The respiratory quotient (or RQ or respiratory coefficient) is a unit-less number used to calculate basal metabolic rate (BMR) from carbon dioxide production.