as 2,700 people were buried prematurely each year in england and wales, although some estimates peg the figure to be closer to 800. in cases of electric shock, cardiopulmonary resuscitation (cpr) for an hour or longer can allow stunned nerves to recover, allowing an apparently dead person to survive. people found unconscious under icy water may survive if their faces are kept continuously cold until they arrive at an emergency room. this "diving response," in which metabolic activity and oxygen requirements are minimal, is something humans share with cetaceans called the mammalian diving reflex. as medical technologies advance, ideas about when death occurs may have to be reevaluated in light of the ability to restore a person to vitality after longer periods of apparent death (as happened when cpr and defibrillation showed that cessation of heartbeat is inadequate as a decisive indicator of death). the lack of electrical brain activity may not be enough to consider someone scientifically dead. therefore, the concept of information-theoretic death has been suggested as a better means of defining when true death occurs, though the concept has few practical applications outside the field of cryonics. causes