A four-year international study led by the University of Southampton found evidence of life after death.
"Contrary to perception, death is not a specific moment but a potentially reversible process that occurs after any severe illness or accident causes the heart, lungs and brain to cease functioning. If attempts are made to reverse this process, it is referred to as 'cardiac arrest'; however, if these attempts do not succeed it is called 'death,'" Dr Sam Parnia, Assistant Professor of Critical Care Medicine and Director of Resuscitation Research at The State University of New York at Stony Brook and the study's lead author, said in a press release.
For the study, the researchers followed more than 2,000 people from the United Kingdom, United States and Austria who suffered cardiac arrests. They found that nearly 40 percent of the patients who survived experienced a feeling of "awareness" when they were pronounced clinically dead and before they were revived.
In the study, a 57-year-old social worker was able to recount the actions of the medical staff while he was clinically dead for three minutes. During the period, the man recalls watching doctors attempting to restart his heart from the corner of the room. He also heard two "bleeps" from a machine in the operating room at three minute intervals.
Parnia said that "conscious awareness" continues to remain in the first few minutes after death. It occurs for up to three minutes after the heart stops beating and even when the brain isn't working.
The researchers said that recollection of such experiences has the potential to be more frequent. However, drugs or sedatives inhibit memory retention.
"This suggests more people may have mental activity initially but then lose their memories after recovery, either due to the effects of brain injury or sedative drugs on memory recall," said Parnia.
In the past, patients presumed these vivid death experiences were hallucinations or illusions but they were in fact related to actual events. Majority of the patients fail to recollect these near death experiences due to the effects of brain injury or sedative drugs on memory circuits.
The finding is published in the journal Resuscitation.