For some, their near death experience was blissful, for others they felt sad and scared. Photo / iStock
Despite numerous theories and religious beliefs, what really happens after death is one of life's great mysteries.
But people may feel that much closer after reading the responses to a question posed in an online forum.
Answering the question "How does death feel?" in the Quora forum, users shared their stories of coming back to life after being declared clinically deceased.
• Scroll down for fellow Herald readers' near death experiences
They range from "blissful" feelings to disappointment at not reaching personal goals to being filled with a sense of "terrifying emptiness".
More than 18,000 have read her account of being poisoned by carbon monoxide when she was 11 years old and living in the former Soviet Union.
"I can just see it now, lulling me to sleep, covering me with its heavy and invisible blanket of death.
"Next, I felt my heart racing, my head literally buzzing as if there were a bee hive inside it, and it felt as if there were two knives stuck in either side of my head. I knew that I was going to die right then, right now.
"It was a certain feeling of total emergency one gets, like an internal alarm that screams and hijacks your mind, and I knew that I only had moments to save my life, if only I could figure out what to do."
She says her and her mother tried to call for help before blacking out.
"We were dying. And nobody, nobody in the world could hear us," she wrote. "Next, I remember seeing something like a plasma of colors all around me, with a very strange visual perspective.
"It first looked like liquid clouds, something like the telescope pictures of galaxies, with colors melting into each other, neither far, nor near, and all around me and 'through' me, in a pan-vision."
She said she thought it was "so beautiful" and described a feeling of being lifted, "like my body was a huge lung and it just inhaled and disappeared, and suddenly, an instant release from what now I constantly feel - gravity."
"It felt like being rising up (sic), with a definite sense of direction, and inhaling and expanding. I tried to look at myself, but I was not there.
"That shocked me, but did not scare me. Also, I did not feel alone. There were 'others' whom I could not see, but only knew that they were there because they 'talked' to me.
"It was as if they were encouraging and welcoming me. I felt this infinite vastness, but also the absence of time, like everything was collapsed into a zero and happened at the same time.
"The last thing I remember is wanting to be somewhere else and being instantly there, and that surprised me and delighted me. I was so infinitely happy."
Vera was saved by her father. Doctors initially told him it was too late. She had been clinically dead for between 15 and 45 minutes.
At her father's insistence, medics tried to revive her and successfully brought her back.
She said she lives in peace armed with the knowledge that there is life after death for her.
"Even when I die someday and change my physical shell to something else, there will always be an I, and the I will never be alone," she concluded.
Another user, named Barbara, shared how she had had three experiences of death, all during heart surgeries.
"Although I could hear perfectly - the beeping of the monitor as I flatlined, the code on the PA, the squeak-squeak of the crash cart wheels, everyone talking at once - I had no other sensation," she wrote.
"As I was sinking into unconsciousness, I felt very cool, relaxed, no need to breathe, no cause for alarm, no pain of any kind, totally peaceful. Everything grew dark around the edges until there was only blackness."
Barbara was revived three times.
While others also wrote of peaceful encounters with death, this wasn't the case for everyone.
Aaron described his experience as "remarkable and unforgettable" but didn't get a feeling of peace.
"The moment I realised I was on my way out was sad. Particularly because I was aware my mother was in the room watching as medical professionals did their best to keep me alive," he explained.
"I felt guilt, shame, and profound disappointment for not achieving my personal goals. I accepted my fate in some way. The physical sensations were almost nonexistent."
He said he wasn't scared, "just disappointed".
It was a similar scenario for Emmanuel who wrote about being in intensive care after suffering severe pneumonia.
He believes he experienced near death while he was there.
"There wasn't anything even remotely exciting in what was coming. In fact, it wasn't even anything. No light, no hope, no nothing. Only darkness and loneliness.
"There was no pain, just darkness, extreme vulnerability, extreme fragility and nothing. It wasn't even revolting or scary, just infinite sadness and nothingness.
"After a while in intensive care, my life came back to me, and then it was another story entirely. - I learnt that excruciating pain is actually a very good sign, something that belongs to the living and that welcomes you back to life.
"I have actually quite a cheerful memory of it, even though it was horrible. But at least, "horrible" exists. Based on this experience, I'm inclined to feel that there is nothing after our life."
• What is a Near Death Experience?
The term Near Death Experience was first coined in the book Life After Life by Dr Raymond Moody in 1975.
People who have had such an experience commonly report seeing bright lights and watching their life flash before their eyes. They describe intense feelings of peace and of making a conscious decision or being encouraged by others to return to their body.
Scientists believe possible explanations are found in the physical changes in a stressed or dying brain, imperfect anaesthesia and the body's neurochemical response to trauma.
• Herald reader's share their near death experiences
I got electrocuted once. It carried on for what was an extended period with me seeing no way of getting off the live cable. I sort of came to the conclusion that this was the end.
I was accidentally poisoned with industrial strength degreaser that stripped my stomach lining, entered my bloodstream and knocked out my central nervous system. By this time I was hooked up to the machine that goes "beep" in my doctors office with my boss.