Fig. 1. Boutilier's hypothetical time course of cellular ATP-turnover during anoxia or hypothermia includes the events that promote energy imbalance and cause cell death (red line; Boutilier, 2001a). Neither hypoxia-tolerant nor hypoxia-sensitive cells can survive prolonged energy imbalance, but cells of hypoxia-tolerant animals are adapted to avoid energy imbalance through the coordinated suppression of energy demand and energy supply (inset). Reversible metabolic suppression thus greatly extends hypoxic survival time. (From Boutilier, 2001a.)