The Telegraph online reports that scientists at the University of Southampton have found evidence that awareness can continue for at least several minutes after clinical death, which was previously thought impossible.
The largest ever medical study into near-death and out-of-body experiences has discovered that some awareness may continue even after the brain has shut down completely.
This controversial subject has, until recently, been treated with widespread scepticism. But the scientists have spent four years examining more than 2000 people who suffered cardiac arrests at 15 hospitals in the UK, US and Austria. They found that nearly 40% of people who survived described some kind of 'awareness' during the time they were clinically dead before their hearts were restarted.
Despite being unconscious and 'dead' for 3 minutes one 57-year old man recounted the actions of the nursing staf in detail and described the sound of the machines, as he was being resuscitated.
"We know the brain can't function when the heart has stopped beating," said Dr Sam Parnia, a former research fellow at Southampton University, now at the State University of New York, who led the study.
"But in this case, conscious awareness appears to have continued for three minutes into the period when the heart wasn't beating, even though the brain typically shuts down within 20-30 seconds after the heart has stopped.
"The man described everything that had happened in the room, but importantly, he heard two bleeps from a machine that makes a noise at three mnute intervals. So we could time how long the experience lasted.
"He seemed very credible and everthing that he said had happened to him had actually happened."
Of 2060 cardiac arrest patients studied, 330 survived and 140 said they had experienced some kind of awareness while being resuscitated.
Although many could not recall specific details, some themes emerged. One in five said they had felt an unusual sense of peacefulness while nearly one third said time had slowed down or speeded up.
Some recalled seeing a bright light, a golden flash or the Sun shining. Others recounted feelings of fear or of drowning or being dragged through deep water. 13 per cent said they had felt separated from their bodies and the same number said their senses had been heightened.
Dr Parnia believes many more people may have experiences when they are close to death but drugs or sedatives used in the process of resuscitation may stop them remembering.
"Estimates have suggested that millions of people have had vivid experiences in relatiion to death but the scientific evidence has been ambiguous at best.
"Many people have assumed that these were hallucinations or illusions but they do seem to correspond to actual events.
"And a higher proportion of people may have vivid death experiences, but do not recall them due to the effects of brain injury or sedative drugs on memory circuits.
"These experiences warrant further investigation."
The study was published in the journal Resuscitation.
Dr Jerry Nolan, Editor-in-Chief of Resuscitation said, "Dr Parnia and his colleagues are to be congratulated on the completion of a fascinating study that will open the door to more extensive research into what happens when we die."