Fig. 2. Effects of sustained exercise, fatigue, and subsequent recovery, on rates of O₂ uptake (_O2; mean ± S.E.M.); arterial blood pH (pHa), P_O2 (Pa_O2) and total O₂ content (Ca_O2); red muscle P_O2 (PRM_O2), and the arterial to red muscle P_O2 gradient (Pa_O2–PRM_O2). Data are provided for rainbow trout swimming at two sustained speeds in body lengths s^–1 (BL s^–1); at their maximum sustained swimming speed (Max); immediately upon fatigue (note that _O2 data are not available for this instance), and at 1 h and 2 h of recovery (Rec). NA, data not available. N=5 in all cases, for those variables where exercise elicited statistically significant effects by one-way ANOVA for repeated variables, a common superscript indicates no significant difference between means by Bonferroni post-hoc test (P<0.05).