How Near-death Experiences Work

Brain Pictures Find out what makes an experience an NDE, who typically has them and how people have tried to explain them. See more brain pictures.

Near-death experiences (NDE­s) are common enough that they have enter­ed our everyday language. Phrases like "my whole life flashed before my eyes" and "go to the light" come from decades of research into these strange, seemingly supernatural experiences that some people have when they're at the brink of death. But what exactly are NDEs? Are they hallucinations? Spiritual experiences? Proof of life after death? Or are they simply chemical changes in the brain and sensory organs in the moments prior to death?

In this article, we'll discuss what makes an experience an NDE and who typically has them. We'll also explore spiritual, philosophical and scientific theories for why they happen.



­­Dr. Raymond Moody coined the term "near-death experience" in his 1975 book, "Life After Life." Many credit Moody's work with bringing th­e concept of the near-death experience to the public's attention, but reports of such experiences have occurred throughout history. Plato's "Republic," written in 360 B.C.E., contains the tale of a soldier named Er who had an NDE after being killed in battle. Er described his soul leaving his body, being judged along with o­ther souls and seeing heaven [ref].

For the purposes of this article, a near-death experience is any experience in which someone close to death or suffering from some trauma or disease that might lead to death perceives events that seem to be impossible, unusual or supernatural. While there are many questions about NDEs, one thing is certain -- they do exist. Thousands of people have actually perceived similar sensations while close to death. The debate is over whether or not they actually experienced what they perceived.

In the next section, we'll take a look at some of the traits of near-death experiences.


Near-death Experience Traits

Most NDEs share certain common traits, but not all NDEs have every trait and some NDEs don't follow a pattern at all. Here are the traits that "typical" NDEs share:

  • ­­Int­ense, pure bright light - Sometimes this intense (but not painful) light fills the room. In other cases, the subject sees a light that they feel represents either Heaven or God.
  • Out-of-body experiences (OBE) - The subject feels that he has left his body. He can look down and see it, often describing the sight of doctors working on him. In some cases, the subject's "spirit" then flies out of the room, into ­the sky and sometimes into space.
  • Entering into another realm or dimension - Depending on the subject's religious beliefs and the nature of the experience, he may perceive this realm as Heaven or, in rare cases, as Hell.
  • Spirit beings - During the OBE, the subject encounters "beings of light," or other representations of spiritual entities. He may perceive these as deceased loved ones, angels, saints or God. ­
  • ­The tunnel - Many NDE subjects find themselves in a tunnel with a light at its end. They may encounter spirit beings as they pass through the tunnel.
  • Communication with spirits - Before the NDE ends, many subjects report some form of communication with a spirit being. This is often expressed a "strong male voice" telling them that it is not their time and to go back to their body. Some subjects report being told to choose between going into the light or returning to their earthly body. Others feel they have been compelled to return to their body by a voiceless command, possibly coming from God.
  • Life review - This trait is also called "the panoramic life review." The subject sees his entire life in a flashback. These can be very detailed or very brief. The subject may also perceive some form of judgment by nearby spirit entities.

Near-death experiences and out-of-body experiences are sometimes grouped together, but there are key differences. An OBE can be a component of an NDE, but some people experience OBEs in circumstances that have nothing to do with death or dying. They may still have spiritual elements or feelings of calm. OBEs can happen spontaneously, or drugs or meditation can induce them.


In the next section, we'll take a look at who typically has NDEs and how they're affected.


Who Has NDEs?

Books on NDEs include both first-person accounts and scientific studies.

­ In 1982, pollster George Gallup, Jr. and author William Proctor released "Adventures in Immortality," a book about NDEs based on two Gallup polls specifica­lly addressing near-death and belief in the afterlife. This poll remains the most widely used source for statistics about NDEs.

Gallup and Proctor found that 15 percent of all Americans who had been in near-death situations reported NDEs. Of those, 9 percent included a "classic out-of-body experience," while 11 percent included entering another realm or dimension and 8 percent featured the presence of spiritual beings [ref]. Only 1 percent reported negative NDEs. But these numbers are more than 20 years old, and other researchers, whose studies are usually on a smaller scale, report statistics on NDEs that can vary widely from the 1982 poll.


A statistical analysis of more than 100 NDE subjects revealed that prior religious belief and prior knowledge of NDEs did not have an appreciable effect on the likelihood of having an NDE [ref].

Other research has focused on the effect an NDE has on the subject's life. Kenneth Ring, one of the most prolific researchers and authors of NDE studies, reports a large number of subjects who gain self-confidence and become more extroverted after an experience. One of Ring's studies quantified changes in subjects' attitudes toward life. These generally include a sense of purpose in life, an appreciation of life, and increase in compassion, patience and understanding and an overall feeling of personal strength. A small percentage of subjects reported feelings of fear, depression and a focus on death. Ring also found that NDE subjects tend to feel a heightened sense of religious feeling and belief in a spiritual world. However, he notes that this does not necessarily translate into an increase in church attendance -- it is more of an internal, personal increase in religious and spiritual feelings. Finally, people who go through NDEs often find that they do not fear death, and feel that a positive experience will be awaiting them when they actually die.

Next, we'll examine the spiritual and supernatural theories that seek to explain near-death experiences.


Supernatural Theories

­Theories explaining near-death experiences fall into two basic categories: scientific­ explanations (including medical, physiological and psychological) and supernatural explanations (including spiritual and religious). Of course, these explanations can be neither proven nor disproven. Acceptance of supernatural explanations is based on faith and spiritual and cultural background.

The most basic supernatural explanation is that someone who goes through an NDE is actually experiencing and remembering things that happen to their disembodied consciousness. When they are near death, their soul leaves their body and they begin to perceive things that they normally cannot. The soul goes through the border between our world and the afterlife, usually represented by a tunnel with a light at the end. While on this journey, the soul encounters other spiritual entities (souls), and may even encounter a divine entity, which many subjects perceive as God. They are offered a glimpse into another realm of being, often thought to be Heaven, but they are then pulled back, or choose to go back, into their earthly body.


Belief in astral projection connects NDEs with other forms of out-of-body experiences. Astral projection is the ability of an "astral self" to travel outside the body. In an NDE, this astral self, or soul, spontaneously leaves the body and travels freely to other places. A few cases of NDEs seem to offer proof that people actually experienced events from a point of view different from that of their earthly body. People who were unconscious, non-responsive, had their eyes closed or had been declared clinically dead have reported details of procedures done to them and people who were present in the room [ref]. Some NDE subjects who suffered from permanent blindness have reportedly been able to identify the color of a doctor's shirt, for example [ref].

For those with a strong belief in Judeo-Christian theology, NDEs represent proof that we have souls, that they continue to exist after we die and that Heaven and Hell are real places. Some believe that NDEs are the work of Satan, who seeks to exploit people's vulnerability at the time by appearing as "an angel of light." Satan's ultimate reason for this deception is unclear.

Other NDE theories are a bit more esoteric. Some believe that an NDE represents a psychic connection to higher-level intelligent beings from another dimension. These beings may be humans who have evolved their souls beyond the birth-death-reincarnation cycle, thus offering a glimpse of humanity's future as high-order spiritual beings. Sometimes, an NDE can even offer a literal view into the future, as in the apocalypse prophecy NDEs mentioned earlier.

It is interesting to note that non-Judeo-Christian religions have stories and descriptions of death that seem to explain many of the common NDE traits. Buddhism, for example, describes "the clear light of death," as well as demonic embodiments of moral failure. The soul's goal is to recognize both the light and the apparitions as projections of the soul's own nature, not something objectively real. If that happens, the soul may escape the birth-death-reincarnation cycle and reach nirvana [ref].

Next, we'll find out what science has to say about the NDE.


Scientific Theories

­Science cannot ultimately explain why some people have near-death experiences. That's not to say that current scientific explanations are incorrect, but NDEs are complex, subjective and emotionally charged. Further, ma­ny aspects of NDEs cannot be tested. We can't run a test to determine if someone actually visited Heaven and met God or purposely take someone to the brink of death and then resuscitate them in a lab to test their out-of-body perception.

Nevertheless, medical science offers compelling evidence that many aspects of NDEs are physiological and psychological in nature. Scientists have found that the drugs ketamine and PCP can create sensations in users that are nearly identical to many NDEs. In fact, some users think they are actually dying while on the drug [ref].


The mechanism behind some of these strange experiences is in the way our brains process sensory information. What we see as "reality" around us is only the sum of all the sensory information our brain is receiving at any given moment. When you look at a computer screen, the light from the screen hits your retinas, and information is sent to the appropriate areas of the brain to interpret the light patterns into something meaningful -- in this case, the words you are currently reading. An even more complex system of nerves and muscle fibers allows your brain to know where your body is in relation to the space around it. Close your eyes and raise your right hand until it is level with the top of your head. How do you know where your hand is without looking at it? This sensory system allows you to know where your hand is even when your eyes are closed.

Trauma affecting functional areas of the brain, such as the somatosensory and visual cortexes, could cause hallucinations that get interpreted as NDEs.

Now imagine that all your senses are malfunctioning. Instead of real sensory input from the world around you, your brain is receiving faulty information, possibly because of drugs, or some form of trauma that is causing your brain to shut down. What you perceive as a real experience is actually your brain trying to interpret this information. Some have theorized that "neural noise," or an overload of information sent to the brain's visual cortex, creates an image of a bright light that gradually grows larger [ref]. The brain may interpret this as moving down a dark tunnel.

The body's spatial sense is prone to malfunction during a near-death experience as well. Again, your brain interprets faulty information about where the body is in relation to the space around it. The result is the sensation of leaving the body and flying around the room. Combined with other effects of trauma and oxygen deprivation in the brain (a symptom in many near-death situations), this leads to the overall experience of floating into space while looking down at your own body, and then leaving to float down a tunnel.

The peaceful, calm sensation felt during NDEs may be a coping mechanism triggered by increased levels of endorphins produced in the brain during trauma. Many people experience a strange sense of detachment and a lack of emotional response during traumatic events (whether or not they were related to a near-death experience). This is the same effect. NDEs that include visits to Heaven or meetings with God could involve a combination of several factors. Faulty sensory input, oxygen deprivation and endorphin-induced euphoria create a surreal, though realistic, experience. When the subject recalls the encounter later, it has passed through the filter of his conscious mind. Bizarre experiences that seem unexplainable become spirit beings, other dimensions and conversations with God.

The experiences of people whose out-of-body adventures allow them to see and hear events that their unconscious body shouldn't be able to perceive are more difficult to explain. However, it is plausible that unconscious people can still register sensory cues and prior knowledge and incorporate them into their NDE. Whether this is more plausible than the subject's soul floating out of their body is a matter of personal opinion.

Of course, this only scratches the surface of all the possible explanations for an NDE. NDEs seem to offer some hope that death is not necessarily something to be feared, nor is it the end of consciousness. Even science has a difficult time grasping death -- the medical community has struggled with specific definitions for clinical death, organ death and brain death for decades. For every aspect of an NDE, there is at least one scientific explanation for it. And for every scientific explanation, there seem to be five NDE cases that defy it.

For lots more information on near-death experiences and related topics, check out the links on the next page.


Lots More Information

Related HowStuffWorks Articles

More Great Links


  • Grey, Margot. "Return from Death." Arkana, 1985. 0140190511.
  • Neusner, Jacob, editor. "Death & the Afterlife." Pilgrim Press, 2000.
  • Plato. "The Republic."
  • Ring, Kenneth. "Life at Death." Coward McCann, 1980.
  • Ring, Kenneth. "Heading Toward Omega." Quill, 1985.
  • Rogo, D. Scott. "The Return from Silence." Aquarian Press, 1989.
  • Weiss, Jess E., editor. "The Vestibule." Pocket Books, 1972, 1997.
  • Williams, Kevin. "People Born Blind Can See During a NDE: Dr. Kenneth Ring's NDE Research of the Blind."
  • Woerlee, G.M. "Darkness, Tunnels, and Light." Skeptical Inquirer Magazine, May 2004.