What are near-death experiences, and what do they tell us?

What do people experience, and how common is it?

The best-known study comes from the Netherlands. Pim van Lommel, a cardiologist (heart doctor), and his colleagues followed 344 patients who were revived after cardiac arrest in ten Dutch hospitals. They published the results in The Lancet in 2001. Of those patients, 62 (18%) reported an NDE, and 41 (12%) described a deep, “core” experience. The NDEs were not linked to how long the heart was stopped, to the drugs patients were given, or to fear of death beforehand. When the team checked in again 2 and 8 years later, the people who had an NDE had changed over several years in ways that differed from other survivors.

NDEs also happen outside hospitals. In a 2019 online survey of 1,034 people from 35 countries, 106 (10%) reported an experience that met the standard for an NDE. The most common features among everyone who described such an experience were a changed sense of time (87%), very fast thoughts (65%), unusually vivid senses (63%) and feeling separated from the body (53%). The survey also asked about unpleasant feelings, and almost half of the NDEs were described as stressful. Frightening NDEs are real, and people who had one deserve the same care as anyone else.

How do researchers decide what counts? In 1983, researcher Bruce Greyson published the NDE Scale. It has 16 questions, such as “Did you see, or feel surrounded by, a brilliant light?” and “Did you see deceased or religious spirits?” Each answer scores 0 to 2 points, and a score of 7 or more usually counts as an NDE. The scale is a big reason studies from different countries can be compared.

Can people see and hear things while their heart is stopped?

Some people say they watched their own rescue from above. The AWARE studies, led by Sam Parnia, a researcher in critical care and resuscitation, tried to test this. They built in tests of what people could see and hear: targets a person could report only if they had truly been aware during the rescue.

The first AWARE study (2014) tracked 2,060 cardiac arrests. Only 140 survivors completed interviews. Nearly half (46%) had some memories, 9% had NDEs, and 2% described seeing and hearing real events during their resuscitation. One person had a period of awareness that could be verified, at a time when the brain was not expected to be working.

AWARE II, published in 2023, went further. It covered 567 in-hospital cardiac arrests at 25 sites. Only 53 people (9.3%) survived, and 28 were interviewed. Of those, 11 (39%) had memories or perceptions that suggested some awareness, and 6 described what the team calls a “transcendent recalled experience of death.” Nobody identified the hidden image shown on a computer. One person identified a sound played through headphones. Brain recordings also showed something surprising: patterns like normal brain activity appeared as late as 35 to 60 minutes into CPR, even though the brain was badly short of blood and oxygen.

So the tests are hard to run, because so few people survive. The results so far neither prove nor rule out awareness from outside the body.

What might explain NDEs?

Scientists have proposed several brain-based explanations. Each has some evidence and some gaps.

• Low oxygen. The brain starved of oxygen may produce light and tunnel effects. But van Lommel’s team argued that if low oxygen were the whole story, most patients whose hearts stopped should report an NDE, and most do not.
• High carbon dioxide. In a 2010 Slovenian study of 52 cardiac arrest survivors, 11 (21%) reported NDEs. Those with higher carbon dioxide levels in their blood were more likely to have one. It was a small study, and it found a link, not a proven cause.
• Dream-like sleep breaking into waking. In REM intrusion, parts of dreaming sleep spill into waking life. A 2006 study by Nelson and colleagues found it was more common in 55 people with NDEs than in matched people without them. Critics said the comparison group was poorly chosen: it was drawn from medical center staff and their contacts. The 2019 online survey found the same link with a different method: 47% of people with NDEs reported REM intrusion, compared with 14% of people with no such experience.
• A surge in the dying brain. In a 2013 study in rats, Borjigin’s team at the University of Michigan found a burst of fast, highly organized brain waves within 30 seconds after the heart stopped. In 2023, the team looked at four dying patients in comas after breathing support was removed. Two showed a similar surge, including in brain areas thought to matter for conscious experience. These patients did not survive, so no one could learn what, if anything, they experienced.

In 2025, a group of researchers in Nature Reviews Neurology proposed one model that combines many of these pieces, from brain chemistry to psychology and evolution. A few months later, other scientists published letters questioning it, so the debate is active.

What is the strongest objection, and what do people get wrong?

The strongest objection to brain-only explanations comes from psychiatrist Bruce Greyson and colleagues at the University of Virginia. Responding to the 2013 rat study, Greyson and colleagues pointed out that nobody can know what the rats experienced. They noted that in people, brain waves slow down within seconds of cardiac arrest and go flat within 10 to 20 seconds. They added that many NDEs happen with no cardiac arrest at all, and that only 10 to 20% of people whose hearts stop report one. Every rat showed the same surge. A brain effect that happens in everyone cannot, by itself, explain an experience only some people have. Borjigin’s team replied that experiments like theirs lay a foundation for understanding NDEs.

People on both sides often make one mistake. Some say NDEs prove life after death. Others say NDEs are “only” brain chemistry, as if that makes them less real or less meaningful. Neither follows from the evidence. Finding the brain activity that goes with an experience does not tell us what the experience means. And a powerful experience, by itself, cannot show what lies beyond death, because everyone who reported one came back.

Where can people of faith and skeptics agree?

They can agree that NDEs happen, that they are often deeply meaningful, and that many people are changed by them for years. They can agree that some NDEs are frightening and deserve care, not dismissal. They can agree that careful studies, like AWARE, are the fair way to test claims. And they can agree that whether an NDE is a glimpse of an afterlife is a question about meaning and belief. Science can study the experience, but it cannot follow anyone past death to check. For more on that larger question, see our story What Happens When We Die?

How can you check it yourself?

• Read the study summaries. The Lancet, AWARE and AWARE II abstracts are free to read through their DOI links.
• Look at the numbers behind a claim: how many people were studied, how many survived, and how many were interviewed.
• Ask whether a study was prospective, meaning people were followed from the start, or relied on stories gathered later. Prospective studies, like van Lommel’s and AWARE, gather accounts soon after the event instead of years later.
• If you had an NDE, the Greyson scale questions can help you put words to it. Talking with a doctor, counselor or faith leader you trust can help too.

Our magazine story What Do Near-Death Experiences Tell Us? looks at these questions from another angle.