Fig. 3. (A) Arterial P_CO2, (B) blood pH and (C) plasma bicarbonate concentration in trained and untrained turtles swum from 0 to 2 h during recovery from anoxic submergence. There was no significant interaction between time and treatment for any of the parameters. Values are mean ± S.E.M. (N=6–9). The pooled means of the 2 h active recovery/trained treatment were significantly higher than those from the other treatments for arterial P_CO2 and blood pH. Differing letters indicate significant differences between time points for pooled means (two-way RM-MANOVA, Student's t-test, P<0.05). PR, passive recovery; AR, active recovery; U, untrained; T, trained. 1 torr=133.3 Pa.