Fig. 2.

Example of a Z-transformed respirometry trace from 5 rest-associated apnoeas in one individual. Peaks in the corrected fractional extraction of oxygen (FeC) represent dramatic increases in oxygen consumption (VO₂) during the recovery period. Where the corrected FeC is zero, represents periods of apnoea. These discrete periods where FeC was zero were used to define durations of breath-holds and eupnic recovery periods.