Respiratory Quotient

The respiratory quotient can be represented as

RQ = VCO2/VO2

Where V represents ventilation of the given gas.

This ratio describes how many molecules of CO2 are produced per molecule of oxygen consumed, which depends on the kind of fuel that is being burned. The more oxygen a molecule contains, the greater the amount of produced CO2, and the higher the value. RQ also increases during hyperventilation or metabolic acidosis.

RQsaccharides = 1, RQlipids = 0.7, RQproteins ~ 0.8

A typical RQ value for a subject with a Western diet is 0.8.