Research at the University of Liege in Belgium suggests they may come down to biological rather than spiritual factors.
Scientists analysing 400 people who've had near-death experiences found they aren't only had by people actually dying - pilots, divers and climbers have also experienced them.
And while the 400 people came from a range of cultures, their experiences were often similar - including out-of-body experiences, pleasant sensations and witnessing a bright light, dead family members or life events.
In terms of possible physiological triggers, life-endangering events such as falling and a sudden drop of oxygen to the brain are thought to be potential causes - something which would correlate with a previous study which found that 1 in 5 people who'd suffered a heart attack and were resuscitated had reported a near-death experience.
Speaking to Premier, Dr Steve Laureys (above), who led the research, said: "I don't think we can question what people experience. I think as scientists and medical doctors we should just listen to what these people have experienced and tell us.
"It is a subject that clearly isn't neutral. We can feel this kind of tension between science and religion. All religions have a very strong viewpoint on what's happening after death.
"It's just fascinating to see that all over the planet people have similar experiences.
"We're just trying to understand... without any dogmatic point of view. I don't want to prove anything; I just want to understand."
Listen to Premier's Alex Williams speaking to Dr Steven Laureys:
