What is the difference between respiratory quotient and respiratory exchange ratio?

What is the difference between respiratory quotient and respiratory exchange ratio?

Respiratory Exchange Ratio (RER) directly measures Vol CO2 released/Vol O2 absorbed at the mouth and does not require invasive procedures. Respiratory quotient, on the other hand, measures directly at the tissue, requiring an arterial and venous catheter while monitoring blood pressure for optimal results.

How is the respiratory exchange ratio calculated?

The Respiratory Exchange Ratio (RER) is determined by dividing VCO2 produced by VO2 consumed. The measurement is very similar to the setup required for VO2 consumption, except that the produced CO2 flow is integrated simultaneously with the consumed O2 flow.

What is the respiratory exchange ratio RER )? Explain why it is used to determine the relative contributions of carbohydrate and fat to energy expenditure?

Explain why it is used to determine the relative contributions of carbohydrate and fat to energy expenditure. The RER is the ratio between the rate of CO2 release (VCO2) and oxygen consumption (VO2). Furthermore, fat has more carbon and less oxygen, so the RER of fat measurements are higher.

How is RER used to determine energy expenditure?

The Respiratory Exchange Ratio (RER) (CO2 production/O2 uptake) increase with the exercise intensity and measured under steady state conditions is commonly used to indirectly determine the relative contribution of carbohydrate and lipids to overall energy expenditure (Simonson and DeFronzo, 1990; Pendergast et al.

What is a good respiratory exchange ratio?

An average human has an RER at rest of around 0.8, although this can vary a bit depending on diet and other factors. During a stress test, RER will typically gradually increase to a peak of about 1.2 (again variable depending on the individual).

What is the normal value for the respiratory exchange ratio?

The RER under typical metabolic conditions with stable respiratory function ranges from 0.7 to 1.0. If RER is lower than 0.7 or higher than 1.0, prolonged starvation or excessive recent energy consumption should be suspected, both events representing protocol violation of resting metabolic rate (4).

Why RQ of fat is less than 1?

Fats and proteins contain a smaller number of oxygen atoms than carbon atoms in their molecules. When fats are used as a substrate in respiration, the RQ is less than 1 because the amount of oxygen utilised is always higher than the amount of carbon dioxide released.

What happens to RER as exercise intensity increases?

As the intensity of the exercise increases and carbohydrates become the dominant or primary fuel, the respiratory quotient and the RER increase to between 0.9 and 1.0. Because RER reproducibly increases during exercise, it is considered a parameter that can document maximal effort.

What is RER and how is it calculated?

The Respiratory Exchange Ratio (RER) is defined as VCO2 produced divided by VO2 consumed (where V is Volume). Accordingly, when performing these measurements, precise determination of inspired and expired volumes plus accurate gas concentration level recording is required.

What does it mean when RER is greater than 1?

Respiratory Exchange Ratio (RER) makes it possible to calculate which specific fuel (protein, fat or carbohydrate) is being oxidized. In case the value is greater than 1, it indicates anaerobic respiration as a result of more carbon dioxide being generated than the oxygen that is being consumed.

What is RQ of anaerobic respiration?

The RQ of anaerobic respiration is infinite. This is because, in anaerobic respiration, the total volume of oxygen consumed is zero as this process occurs in the absence of oxygen and only carbon dioxide is produced. Therefore : RQ = CO2 / O2 = 2/0 = infinity.

Why RQ of fat is less than glucose?

Fat contain more oxygen than glucose c. Fat consumes more O2 and releases less CO2 as compare to glucose d.