respiratory quotient (RQ), the ratio of the volume of carbon dioxide produced to the volume of oxygen consumed per unit of time by the body under steady-state conditions. Depending on the net metabolic needs of all parts of the body at a given moment, the ratio ranges from 0.7 to 1 and averages around 0.8. The RQ varies for different metabolic fuels: the RQ of fat is lower than that of protein, which is lower than that of glucose. Also called metabolic respiratory quotient.
