Michael Shermer in Scientific American:
Have you ever died and come back to life? Me neither. No one has. But plenty of people say that they have, and their experiences were the subject of an episode of Larry King Live last December on which I appeared as the token skeptic among a tableful of believers, including CNN’s medical correspondent Sanjay Gupta, New Age author Deepak Chopra, a football referee who “died” on the playing field, and an 11-year-old boy named James Leininger who believes he is the reincarnation of a World War II fighter pilot.
Dr. Gupta started us off by recalling that when he was in medical school the residents were taught to mark the time of death to the minute, when death can often take anywhere from a couple of minutes to a couple of hours to occur, depending on the conditions. As Gupta noted, people who have fallen into freezing lakes and “died” were not quite dead, and their core body temperatures dropped so rapidly that their vital tissues were preserved long enough for subsequent resuscitation. In other words, people who have near-death experiences (NDEs) are not actually dead!