Fig. 1. (A) An example of the recorded fractional O₂ content of the excurrent air from the respirometer (FE_O2) (solid red line) over time. (B) The calculated coefficient of variation (CV=standard deviation divided by mean) (solid green line). A chosen CV threshold (red line in B) was used to derive the FI_O2 baseline (blue line in A). (C) Calculated rate of aerial O₂ consumption (_O2) (green line) for each pair of recorded FE_O2 and derived FI_O2 values. A _O2 threshold (red line) was chosen to separate breaths from noise.