What does it feel like to die?

In March 2012 the Bolton Wanderers Football Club midfielder Fabrice Muamba collapsed on the field of play in a Premier League match against Tottenham Hotspur. He had suffered a heart attack and although he was apparently dead with no vital signs for a considerable length of time, he survived. In fact, he made a rapid recovery and was discharged from hospital a month later. The only sour note in what has been a remarkable return to health is the recent announcement of his enforced retirement from professional football.

As for the incident itself, Fabrice Muamba is on record describing his impressions of what happened. At first he felt a surreal dizziness as though he was running along inside someone else's body. The last thing he remembers is seeing two of the Tottenham player Scott Parker. Interestingly, he reports no feeling of pain as the cardiac arrest occurred and unconsciousness took hold.

I can't be the only football fan whose initial empathy for Fabrice Muamba and his family was the starting point for a deeper reflection upon the episode. Obviously, it is shocking that this could happen to a fit young 23 year old professional sports person. But beyond that, it certainly put my own mortality into sharp perspective. Or put bluntly, it made me think about my future death. When will it come? (Hopefully not for many years!) What will be its circumstances? (Peaceful, I hope!). And very simply - what does it feel like to die?

Death is a fundamental issue for human beings. We are unique amongst all the creatures on earth in having the cognitive capacity to possess the knowledge that one day we will die. This means that we have to come to terms with our deaths as we go about our lives. I am not an acquaintance of Fabrice Muamba and so I can't ask him about his experiences first hand. Yet I have no doubt that doing so would provide insights that would be useful in helping me to better come to terms with death.

However, as a psychologist, I do have access to the vast library of psychological research that has been carried out on many and varied topics. Though rare, cases of succesful resuscitation following protracted periods of clinical death, where a patient’s breathing and heart beat stop, do occasionally happen. One morning I decided to search the psychological research database to see what studies had been carried out with such survivors. One particular paper caught my eye for the Cool Psychology blog.

Around the turn of the millennium, Sam Parnia and his colleagues at Southampton General Hospital in the south of England approached all the patients in the hospital that been resuscitated following a heart attack in one year. These patients could easily be identified thanks to the telephone switchboard operators who routinely log all resuscitations as they are called in through the hospital's emergency phone system. There were 63 such patients and they were all interviewed. This group was ideal to form the basis of the study because cardiac arrest patients exhibit two out of the three criteria required to pronounce an individual dead - absence of cardiac output (no heartbeat), and absence of respiratory effort (not breathing). In fact many also exhibit the third criterion of fixed dilated pupils.

The research was in three parts. In the first part, each patient was simply asked whether they had any memories from when they were unconscious following their heart attack, and if so to recount them as clearly as possible. They found that seven individuals could recall their thoughts during the time they were unconscious, which is eleven per cent of the full group.

"Near Death Experience" is a recognised syndrome comprising of a specific pattern of thoughts and memories experienced during an episode of clinical death. A scoring system exists for classifying near death experience. Known as the "Greyson Scale", it consists of a list of consistently reported near death experiences including, among others, feeling time speed up or slow down, recalling scenes from the past, feelings of peace and harmony with the universe. This first part of the Southampton research aimed to distinguish between true near death experience and more random thoughts and memories during the unconsciousness. The Greyson scale was used to assign a score to the experiences recounted by each participant - the more experiences on the scale that are recounted, the higher the given score.

The Southampton patient group recounted several experiences during their unconsciousness. They remembered coming to a point or border of no return, feelings of peace, pleasantness and joy, heightened sensual awareness and a feeling of time speeding up. Four of the patients were classified as having had a true near death experience. Two others remembered some details commonly encountered during near death experience but not quite enough to be classified in the first group. The other patient recalled a less typical experience of people jumping off a mountain.

One of the classic near death experiences reported previously is the sensation of looking down at oneself from a viewpoint close to the ceiling. This is known technically as an "out of body experience". The second part of the study assessed out of body experiences in a very simple yet very clever (and really cool) way. The researchers suspended boards from the ceilings of all of the wards in the hospital. These boards had writing and figures drawn on their upper sides that would only be visible from a vantage point near the ceiling. Therefore, any participants reporting an out of body experience could reasonably be asked to describe what they saw on the upper sides of the boards as a test of whether their experience was real or imagined.

That seems to me to be an astonishing amount of trouble to have gone to in order to investigate this phenomenon. But, still, it perfectly captures the true essence of what science is - using logical tests to gather evidence as to whether some phenomenon is true or not. Science is not all about lab coats, high tech gadgets and undecipherable equations. These investigators simply and elegantly used very low-tech painted boards to set about gathering evidence for out of body experiences.

Unfortunately, though, despite having gone to all the trouble of installing these aids, none of the seven patients with memories from their period of unconsciousness reported viewing themselves from above. Therefore, sadly, this unsophisticated but ingenious research technique could not properly be put to use in the study.

The third part of the study aimed to find out whether the body's physiological state during cardiac arrest had any bearing on the patients being able to remember their thoughts while they were unconscious. The researchers were allowed access to the patients' medical notes and these recorded the levels of oxygen, sodium and potassium in the blood during the resuscitation. To try and tease apart how these may have been affecting the patients the study drew a comparison between the four patients that were classified as having had a true near death experience, and the 59 remaining patients in the study that did not. There was one very interesting difference between the two groups - blood oxygen levels were higher in the near death experience group of patients.

This is intriguing because one of the leading theories of near death experience at the time was that feelings such as heightened sensual awareness and time speeding up came about due to a lack of oxygen in the brain. It was thought that these phenomena occurred as the brain was starved of oxygen. The Southampton study instead suggests that rather than a lack of oxygen, it is the opposite, an availability of brain oxygen that seems necessary for a vivid near death experience. There is a logic to this because better brain oxygenation would allow for improved cognitive function during the resuscitation, which would explain the more vivid experience and the ability to commit it to memory.

What a wonderful piece of research. This paper is a worthy addition to the Cool Psychology blog because it has an elegance of design that is to be admired. Following up all the cardiac arrest sufferers at the hospital provides an insight into what proportion of people will likely experience conscious thought in the moments leading up to death - around ten per cent. It was certainly innovative to collect physiological information as well as the interview responses. Thanks to that we know that high blood oxygen levels during cardiac arrest are probably required to support a level of brain activity sufficient to register and form memories during the experience. But it was an inspired idea to fix message boards just below ceiling height to seek evidence for out of body experience. It was just unfortunate that none of the patients had an out of body experience, and so nothing can be learned from this highly original approach.

The paper is doubly welcome in the Cool Psychology blog because it gives some very well founded insights into an under-researched but fundamental human question: What does it feel like to die? Fascinatingly, cardiac arrest appears not to be traumatic - of those patients that could remember the experience at all, none reported it as unpleasant or painful. Moreover, memories that could be recalled point to a joyful, peaceful experience accompanied by a pleasantly heightened sensual awareness. These findings chime with Fabrice Muamba's re-telling of his experiences during a prolonged cardiac arrest. He said that he felt no pain whatsoever - just an odd, difficult to explain feeling.

So, what does it feel like to die? On this evidence, death by cardiac arrest seems to feel either like nothing, or something pleasant and perhaps slightly mystical. There was no evidence that having a cardiac arrest is painful. How reassuring. I take comfort from the notion that death may not necessarily be something to be feared. This being the case I think we can all rest easier as we carry on our lives in death's ever present, if perhaps now slightly fainter shadow.

The reference and a link to the full paper describing this study is included below. This paper was published in the peer review academic journal named Resuscitation. You can read the abstract (a short summary) of the article online for free by clicking on this link. There is a charge for obtaining the full paper unless you are able to access a library at a university or hospital with a subscription to the journal. Otherwise you could try e-mailing the lead author, Sam Parnia and ask very politely for a pdf copy.

Parnia, S, Waller, DG, Yeates, R, Fenwick, P (2001). A qualitative and quantitative study of the incidence, features and aetiology of near death experiences in cardiac arrest survivors. Resuscitation, 48, 149-156. Link