Overall, chemical-based theories lack precision and can’t explain the full range of near-death experience features people experience.
Researchers have also explained near-death experiences via cerebral anoxia, a lack of oxygen to the brain. One researcher found air pilots who experienced unconsciousness during rapid acceleration described near-death experience-like features, such as tunnel vision.
Lack of oxygen may also trigger temporal lobe seizures which causes hallucinations. These may be similar to a near-death experience.
But the most widespread explanation for near-death experiences is the dying brain hypothesis. This theory proposes that near-death experiences are hallucinations caused by activity in the brain as cells begin to die.
As these occur during times of crisis, this would explain the stories survivors recount. The problem with this theory, though plausible, is that it fails to explain the full range of features that may occur during near-death experiences, such as why people have out-of-body experiences.
Currently, there is no definitive explanation for why near-death experiences happen. But ongoing research still strives to understand this enigmatic phenomenon.
Whether paranormal or not, near-death experiences are extremely important. They provide meaning, hope, and purpose for many people, while offering an appreciation of the human desire to survive beyond death.
Neil Dagnall, Reader in Applied Cognitive Psychology, Manchester Metropolitan University and Ken Drinkwater, Senior Lecturer and Researcher in Cognitive and Parapsychology, Manchester Metropolitan University.