Fig. 5. The effect of increasing the duration of severe hypoxia on the input pressure P_IN required to maintain a resting cardiac output of 16–17 ml min^–1 kg^–1. (A) P_IN recorded prior to _max1 and prior to _max2; (B) the change in resting P_IN between _max1 and _max2 (N=6–7 in each group). *Significant difference (P<0.05) identified using repeated-measures ANOVA. One-way ANOVA did not reveal any significant differences in the change in P_IN between treatments.