The respiratory quotient (RQ) is infinite when there is no consumption of oxygen in respiration, or in anaerobic respiration .
The RQ is the ratio of the volume of carbon dioxide produced to the volume of oxygen consumed during cellular respiration. In anaerobic respiration, oxygen is not consumed, so the total volume of oxygen consumed is zero. Since the RQ is calculated by dividing the volume of carbon dioxide produced by the volume of oxygen consumed, the result is infinity.
