Fig. 4.
Measures of the partial pressure of end-tidal carbon dioxide and oxygen during baseline (B2), the first hypoxic episode (H1), and end recovery on the initial and final days of the intermittent hypoxia protocol. Average values for the partial pressure of end-tidal carbon dioxide (PetCO2; A) and partial pressure of end-tidal oxygen (PetO2; B) recorded from the last 5 min of baseline 2, the last 2 min of each hypoxic episode (a cumulative average for all episodes is shown), and from the 30-min end-recovery period. Note that PetCO2 was similar on each day of the protocol during baseline, hypoxia, and end recovery following exposure to intermittent hypoxia. In contrast, note that PetO2 was significantly greater on the final compared with the initial days of the protocol during both baseline and end recovery. Moreover, note that PetO2 during end recovery was greater compared with baseline for the trials completed in the morning and evening on the initials and final days of the protocol. *Significantly different from initial days of the intermittent hypoxia protocol. §Significantly different from baseline.