8:35am UK, Thursday April 08, 2010
Near death experiences could be caused by something as mundane as raised levels of carbon dioxide, scientists suggest.
Improved resuscitation rates mean more NDEs are being reported
People who claim to have felt such experiences describe them as life flashing before their eyes, feelings of peace and joy and supernatural encounters.
An "NDE" is usually an experience described by someone who has been declared clinically dead or appears very close to death.
Improved resuscitation rates mean more NDEs are being reported but the causes for them are not known.
Many scientists put them down to hallucinations while psychics or religious groups are more likely to consider them as evidence of an afterlife.
A number of studies have been undertaken over the years but this is the first one that has taken carbon dioxide levels into consideration.
Slovenia-based scientists studied 52 patients whose hearts had stopped, using questionnaires to determine whether or not they had had an NDE.
Eleven patients reported NDEs, with more incidences among those with a higher concentration of carbon dioxide in the breath and arteries, the study published in Critical Care, said.
Zalika Klemenc-Ketis, who led the research, told Sky News Online: "Our study pointed out a possible effect that carbon dioxide has on the provoking of NDE.
"But we cannot say that this is the only factor that provokes NDE, we have just found out that carbon dioxide is associated with NDE.
"Some theories talk about the role of carbon dioxide in the NDE, because it has been known that in other cases, for example in people at higher altitudes, carbon dioxide might provoke some sort of hallucinations and visions, that could be described as NDE-like experiences."
When asked if the study would rule out paranormal activities, she said: "I don't think that, based on our study, we can say that paranormal believers are wrong.
"We have simply found out that one of the factors that could play a role in provoking the NDE, is carbon dioxide. But a lot still has to be done to totally explain this phenomena."