How Dying Works

A pet's death may be our first experience with dying. See more death pictures.
A pet's death may be our first experience with dying. See more death pictures.
Cohen/Ostrow/Digital Vision/Getty Images

­For some of us, death is something we've only seen on television or on the silver screen. Our perceptions of dying have been shaped by actors gunning for awards in dramatic deathbed scenes or bad guys getting their just deserts as they go down in a blast of bullets. We've postponed turning pages of best-selling books to keep our heroes alive and listened to the heartbreak of loss on the radio. Dying is on the news as well: celebrities dying of overdoses, princesses dying in car accidents and ordinary people dying in terrorist attacks. Death is a concept even young students grapple with in history class, trying to understand the impact of millions dead because of war, disease, natural disasters or concentration camps.

Others of us have witnessed dying in an up close and personal way. We've lost grandparents and parents to degenerative diseases, we've lost siblings and friends to car accidents or we've known someone who was just in the wrong place at the wrong time. When death happens, it often seems unfair. It may also seem unnatural because from the time of our births, we spend a good deal of effort trying to prevent death. We receive childhood vaccines so we don't get sick; we hear strict admonitions to look both ways before crossing the street; we swallow broccoli grudgingly knowing that it's good for us. As we become teenagers, we learn about risk factors that could shorten our lives, from tobacco and alcohol use to unsafe sex and reckless driving. And when we round the bend to adulthood, we start swallowing vitamins and prescription drugs and subscribing to bizarre exercise and beauty regimes in an effort to trick death.


­But death isn't an adversary we can conquer or a battle that is to be won. Rather, it's a natural part of life that occurs sooner or later because our bodies weren't made to last forever. Also, it's the event that gives life meaning. Without the timeline of death, it could be argued, we'd never get around to doing very much at all. In that way, death puts a lot of pressure on us, and we may never feel we're actually ready for it. Additionally, death is a mysterious business; after all, the only ones who know anything about it aren't around to share their knowledge.

In this article, we'll take a look at what we know about the scientific process of dying so far. Death may not always be pretty, but it's a fate that awaits us all. So what exactly is death?


What Is Death?

With CPR, respirators and defibrillators, we now have ways of bringing the dead back to life.
With CPR, respirators and defibrillators, we now have ways of bringing the dead back to life.
Jim Arbogast/Digital Vision/Getty Images

­Over time, death has been defined in many ways. Often, we personify death, with visions ranging from the grisly and gnarled Grim Reaper to the dashingly handsome Brad Pitt in the 1998 film "Meet Joe Black." In the first edition of Encyclopedia Britannica, death was briefly summarized as "the separation of the soul and the body," and this definition generally reflects how our views of death are tied up with our religious beliefs (or lack thereof). Fifteen editions later, the entry was 30 times longer [source: Kastenbaum]. That increase in length is likely due to the greater understanding we have of the human body. But from a purely biological standpoint, death is no easier to define; indeed, medical advances and technology have only made it tougher to determine when a person is, in fact, dead.

Not that identifying death without medical technology was any picnic, either. Imagine for a moment that you lived several hundred years ago. You're at home with the matriarch of the family, who appears to have died. You don't call a doctor for help; rather, you would have called the local priest to make the determination of death. The family and the priest would only have outward signs that the person was dead -- they may have held a mirror to the woman's mouth or a feather above her nose to look for signs of breath. If the mirror didn't cloud or the feather didn't move, then that person was as good as gone. In the 18th century, enough was known about the human body that you would have checked for a heartbeat, but it was still several decades before the invention of the stethoscope. You might have done something known as Balfour's test, which means you would have stuck needles through the skin into the heart. Then you would have watched the top of the needles, which had flags attached, to see if there was movement.


As time went on, though, people realized that even if all the outward signs of life, like respiration and heartbeat, were gone, there was still a chance that the person wasn't quite dead. In fact, tales began to circulate (with the help of one Edgar Allen Poe) that a person could be buried alive. Death was somehow, in some cases, reversible.

Today, we know there's technology that makes death quite reversible. If a person stops breathing, he or she can be hooked up to a ventilator that keeps the respiratory and circulatory systems functional. We have feeding tubes, ­CPR and a whole host of devices that can keep a person alive, if you measure life by a pulse.

But doctors and family members started to think that maybe a pulse wasn't quite enough to qualify someone as alive. There were some patients that never recovered consciousness after being hooked up to these machines. Doctors started using terms like "persistent vegetative state" and "irreversible coma." In 1958, French neurologists described this state as "coma depasse," or a state beyond coma. These people weren't coming back, because their brains were too damaged. Around the same time, doctors had discovered how to transplant organs into those near death to prolong their lives. But there was one problem -- they didn't have enough organs to go around.

Find out how these two situations collided to make a new definition of death on the next page.

Dying Definition

The idea of brain death developed in response to machines that can maintain bodily functions, like respiration.
The idea of brain death developed in response to machines that can maintain bodily functions, like respiration.
David Joel/Photographer's Choice RF/Getty Images

Here was the situation in the 1960s: Doctors had the power to transplant organs and give dying people a new shot at life. At the same time, they had people with viable organs hooked up to machines, and it seemed these people were never coming back. In 1968, Harvard Medical School newly defined death as irreversible damage to the brain, or brain death.

In some ways, Harvard's definition of death is pretty close to Encyclopedia Britannica's original version, if you consider the soul a facet of what makes a person unique and human. The committee at Harvard, in essence, declared that the person was gone when his or her memories and personality, located in the brain, were irretrievably gone. The cortical brain, or the higher brain, is the part where those memories and personality are stored, and some have argued that damage to that higher brain meets the qualifications of brain death. However, most developed countries have signed on to a legal definition of brain death that considers the whole brain, including the brain stem. The brain stem regulates function such as respiration, movement and speech. A determination of brain death requires stringent testing, which you can read about in How Brain Death Works.


­Using the brain as the definition for death has presented many difficulties. It can be hard for friends and family to hear that a loved one is dead when they can see a chest rising and falling and can touch a warm body, even if those states are being maintained by machine. Some people have always found it a little disconcerting that our definition of death was in some ways shaped by a need for organs, and the argument over how much of the brain has to be dead to count is still troubling bioethicists and doctors. And good old technology is always complicating death, because new machines have been able to find extremely small traces of brain activity. When it's your child hooked up to a machine, extremely small traces may be all you need to hold out hope. And with neurological advances being made every day, is it worth keeping someone alive for longer until science finds a cure?

We'll discuss these ethical issues in a later section, but for now, let's get back to the process of dying. Though the legal definition of death is tied to brain activity, you'll rarely see "brain death" as the official cause of death. We're more familiar with causes of death like heart attack, cancer and stroke. Broadly speaking, the events that cause our death can be divided into three categories: accidental deaths, which result from bodily injuries sustained in events like car accidents, falls and drowning; violent deaths due to homicide or suicide; and natural deaths, which include diseases and passings that occur due to old age.

The fact that we can now die just from old age is quite a change from how our ancestors died. With modern medicine, we've defeated many of the infectious diseases and addressed the sanitation issues that may have killed us before. Of course, some areas of the world without access to that kind of health care still die in this way. According to the World Health Organization, the top five causes of death in 2004 in low-income countries included diarrheal diseases and HIV/AIDS, while people in high-income countries were more likely to face these top five killers: coronary heart disease, stroke, lung cancer, lower respiratory infections and pulmonary disease [source: WHO].

These days, people in high-income countries live longer. But with the blessing of a long life span comes the likelihood of death occurring due to a degenerative disease. So while accidental and violent deaths will always take lives, the great majority of us won't die instantly. Death will be more of a drawn-out process, and on the next page, we'll consider how the dying process may happen.

The Dying Process

As death nears, measures can be taken to make the patient more comfortable.
As death nears, measures can be taken to make the patient more comfortable.
Photodisc/Getty Images

As technology helps us to live longer, it will also shape how we die. With a higher-brain definition of death, you're gone when your personality is. With a whole-brain definition of death, you've lost the ability to breathe on your own again. Each breath provides the oxygen necessary for survival to the rest of the body. Very simply, dying starts to happen when your body doesn't get the oxygen it needs to survive.

Different cells die at different speeds, so the length of the dying process depends on which cells are deprived of oxygen. The brain requires a tremendous amount of oxygen but keeps very little in reserve, so any cutoff of oxygen to the brain will result in cell death within three to seven minutes; that's why a stroke can kill so quickly. When blood is cut off from the heart, a heart attack occurs and can also take a life fairly swiftly. But since our bodies aren't designed to last forever, sometimes the body's systems just simply wear out. When someone dies of extremely old age, and the family is gathered around the deathbed, you're basically observing the breakdown of these systems.


There are some outward signs that these systems are slowing down. The person will begin sleeping more to conserve the little energy that's left. When that energy is gone, the individual may lose the desire to eat and then to drink. Swallowing becomes difficult and the mouth gets very dry, so forcing the person to eat or drink could cause choking. The dying person loses bladder and bowel control, but accidents will occur less frequently as those gastrointestinal functions shut down as well and he or she consumes less.

Any ­pain that the dying person feels at this point can usually be managed by a doctor in some way, but it can be unbelievably difficult to watch these final steps of a person's life. The stage right before a person dies is called the agonal phase. The dying person is often disoriented, and it will seem like he or she can't get comfortable. It will also seem, disconcertingly, that the person can't catch a breath. There may be agonizing pauses between loud, labored breaths. If there is fluid built up in the lungs, then that congestion will cause a sound known as the death rattle. As the cells inside a person lose their connections, the person may start convulsing or having muscle spasms.

We can't know exactly how the person is feeling at this point, though those who have had near-death experiences (NDE) seem to agree that the process isn't painful. NDEs appear to have some common characteristics, including a feeling of peace and well-being, a sense of separation from the physical body and a sensation of walking through darkness to enter light. You can read more about NDEs in How Near-death Experiences Work.

Some doctors think that a near-death experience might be due to endorphins that the body releases at the actual moment of death [source: Nuland]. When the heartbeat and breath stop, the person is clinically dead. There's no circulation, and no new reserves of oxygen are reaching cells. However, clinical death also denotes that this is a point where the process is reversible, by means of CPR, a transfusion or a ventilator.

The point of no return is biological death, which begins about four to six minutes after clinical death. After the heartbeat stops, it only takes that long for brain cells to begin dying from lack of oxygen. Resuscitation is impossible at this point.

What you think has happened to the essence of the person at this point is dependent on your religious and cultural beliefs. But as our examination of the postmortem body on the next page will reveal, there's not a lot of time for sitting around and staring at the corpse.

The Body After Death

Left exposed to the elements, dead bodies break down very quickly.
Left exposed to the elements, dead bodies break down very quickly.
Steven Puetzer/Photographer's Choice RF/Getty Images

After the heart stops beating, the body immediately starts turning cold. This phase is known as algor mortis, or the death chill. Each hour, the body temperature falls about 1.5 degrees Fahrenheit (0.83 degrees Celsius) until it reaches room temperature. At the same time, without circulation to keep it moving through the body, blood starts to pool and settle. Rigor mortis, or a stiffening of the body, sets in about two to six hours after death [source: Marchant, Middleton].

While the body as a whole may be dead, little things within the body are still alive. Skin cells, for example, can be viably harvested for up to 24 hours after death [source: Mims]. But some things that are still alive lead to the putrefaction, or decomposition, of the body -- we're talking about little organisms that live in the intestines.


A few days after death, these bacteria and enzymes start the process of breaking down their host. The pancreas is full of so many bacteria that it essentially digests itself [source: Macnair]. As these organisms work their way to other organs, the body becomes discolored, first turning green, then purple, then black. If you can't see the change, you'll smell it soon enough, because the bacteria create an awful-smelling gas. In addition to smelling up the room, that gas will cause the body to bloat, the eyes to bulge out of their sockets and the tongue to swell and protrude. (In rare instances, this gas has created enough pressure after a few weeks to cause decomposing pregnant women to expel the fetus in a process known as coffin birth.)

A week after death, the skin has blistered and the slightest touch could cause it to fall off. A month after death, the hair, nails and teeth will fall out. The hair and nails, by the way, while long rumored to keep growing after death, don't have any magical growth properties. They merely look bigger as the skin dries out. Internal organs and tissues have liquefied, which will swell the body until it bursts open. At that point, a skeleton remains.

Now, most of us don't see that process because the law requires that we do something with the body. There are endless possibilities: We can choose a coffin for our body or an urn for our ashes. We can be embalmed, mummified or frozen. Some cultures were rumored to engage in cannibalistic rituals of consuming the dead, while others left their dead exposed to the elements for animals to cart away. You could donate your body to science or ask for burial at sea. But unless mummified or preserved, bodies eventually disintegrate in the process described above. However, burial in a coffin slows the process tremendously; even the type of soil in which you're buried can make a difference.

Disposal of a dead bod­y is largely regulated by cultural and religious beliefs. Early cultures buried the dead with their favorite possessions (and sometimes their favorite people) for the afterlife. Sometimes, warriors or servants were buried standing up, eternally ready for action. Orthodox Jews shroud their dead and bury them on the same day as death, while Buddhists believe that consciousness stays in the body for three days [source: Mims]. Hindus are cremated, because it's believed that burning releases the soul from the body, while Roman Catholics frown on cremation out of respect for the body as a symbol of human life [sources: Mims; Cassell et al].

Religion and culture will always be intertwined with death, and one large area of influence relates to the ethical questions surrounding the dying process. On the next page, we'll consider some of the issues.

Medical Ethics in Death

After an attack by neo-Nazis left him paralyzed, Noel Martin announced that he would seek medically assisted suicide.
After an attack by neo-Nazis left him paralyzed, Noel Martin announced that he would seek medically assisted suicide.
Christopher Furlong/Getty Images News/Getty Images

We've described the difficulties of defining death. Thanks to medical technology, we can keep our bodies alive even when the brain is dead. To some, it's obvious at what point they want the plug pulled, and they might have legal documents outlining their choices. Documents such as a health care power of attorney and a living will provide guidelines for medical decision-making. The need for such documents has been highlighted by several cases that received national attention, such as those of Karen Ann Quinlan and Terri Schiavo. In both of these cases, family members and doctors disagreed on the point at which life-preserving machines should be disconnected, necessitating a court's involvement.

While those cases involved women who were no longer conscious, the end-of-life decisions made by some who remain conscious are no less troubling. The issue of physician-assisted suicide is obviously a sticky one. We trust our doctors to do what's best for our health, but what if the patient has decided that the best thing would be to avoid prolonged suffering and useless means of treatment? In opinion polls, most Americans demonstrate support for the concept of a doctor helping a patient end a life with painless means, but support immediately drops if the word "suicide" is used instead [source: Grossman].


­The problem generally revolves around how much authority and control -- autonomy -- a person has relating to his or her own death. In contrast to that concept is the idea of beneficence, or the more rational wisdom and care of others. How can one person make a judgment on how much another person suffers? Whose definition of suffering will be used? And what of religions and cultures that take pride in some form of suffering? Can you really make rational decisions in the midst of all these health issues? Questions such as these ensure that physician-assisted suicide will always be an ethical issue, regardless of any law that's passed concerning its use.

For those who choose not to pursue some form of suicide when facing disease, there are other end-of-life decisions. At what point should medicine shift from a regimen trying to cure a person to a treatment that can provide comfort and control pain, a state known as palliative care? Will the person choose to die at home, in a hospital or in a hospice? How can the final days be as meaningful as possible? While we know that grief is a multi-staged process that loved ones endure after a person's death, the dying person also goes through certain stages at the end of life as well. Psychiatrist Elizabeth Kubler-Ross described dying as a progression through denial, anger, bargaining, depression and acceptance. For assistance in dealing with this progression, dying patients may turn to clergy members or other leaders within their faith, or a mental health counselor.

As time goes on, technology may only make the definition of death more ethically challenging. Human beings by and large like to have control over their destinies, and death robs us of that. In some ways, the ethics of death is the fight for who will have control over the dying process -- the person, a doctor, a supreme being. The dying person can plan for a lot -- from the clothes he or she wants to be buried in to the inscription on the tombstone -- but most of us don't get to pick our cause of death. But as we mentioned in the introduction, not knowing when or how death will strike is part of the package, and it's often the part that gets us to write that novel that's been brewing in the back of our brains or to reconcile with a long-estranged family member. It's the process that provokes us to tell loved ones how much they mean to us, for one day they won't be around to hear it.

For more on death and dying, see the links on the next page.

Lots More Information

Related HowStuffWorks Articles

More Great Links

  • Altman, Linda Jacobs. "Death: An Introduction to Medical-Ethical Dilemmas." Enslow Publishers. 2000.
  • British Medical Journal. "Assisted Suicide Laws May Overlook Depressed Patients." ScienceDaily. Oct. 8, 2008. (Dec. 15, 2008)­ /releases/2008/10/081007192534.htm
  • Cassell, Dana K., Robert C. Salinas and Peter A.S. Winn. "The Encyclopedia of Death and Dying." Facts on File. 2005.
  • "death." Encyclopedia Britannica. 2008. (Aug. 12, 2008)
  • "End-of-Life Care: Questions and Answers." National Cancer Institute. Oct. 30, 2002. (Dec. 16, 2008)
  • Fine, Robert L. "From Quinlan to Schiavo: medical, ethical, and legal issues in severe brain injury." Baylor University Medical Center Proceedings. April 5, 2005. (Dec. 16, 2008)
  • Grossman, Cathy Lynn. "When Life's Flame Goes Out: Death is Difficult to Define, Legally and Morally." USA Today. Oct. 5, 2005. (Dec. 16, 2008)
  • Harlevy, Amir and Baruch Brody. "Brain Death: Reconciling Definitions, Criteria and Tests." Annals of Internal Medicine. Sept. 15, 1993. (Aug. 12, 2008)
  • Hughes, James. "Essay: The End of Death?" New Scientist. Oct. 13, 2007.
  • Kastenbaum, Robert. "Definitions of Death." Encyclopedia of Death and Dying. (Dec. 16, 2008)
  • Kolata, Gina. "When Death Begins." New York Times. April 20, 1997. (Aug. 12, 2008)
  • Laureys, Steven and Joseph J. Fins. "Are we equal in death?: Avoiding diagnostic error in brain death." Neurology. Jan. 22, 2008. (Dec. 16, 2008)
  • Lazar, Neil M., Sam Shemie, George C. Webster, Bernard M. Dickens. "Bioethics for clinicians: 24. Brain Death." Canadian Medical Association Journal. March 20, 2001. (Dec. 16, 2008)
  • Lynn, Joanne. "Death and Dying." Merck Manuals Online Medical Library. October 2007. (Dec. 16, 2008)
  • Macnair, Trisha. "Human decomposition after death." BBC. April 2008. (Dec. 16, 2008)
  • Marchant, Jo and Lucy Middleton. "Instant Expert: Death." New Scientist. Oct. 10, 2007. (Dec. 16, 2008)
  • Mims, Cedric. "When We Die: The Science, Culture, and Rituals of Death." St. Martin's Press. 1998.
  • "Near-Death Experiences Illuminate Dying Itself." New York Times. Oct. 28, 1986. (Dec. 16, 2008)
  • Nuland, Sherwin B. "How We Die: Reflections on Life's Final Chapter." Knopf. 1994.
  • Philipkoski, Kristen. "Brain Dead Means Dead." Wired. April 9, 2001. (Aug. 12, 2008)
  • Plonk, William M. Jr. and Robert M. Arnold. "Terminal Care: The Last Weeks of Life." Journal of Palliative Medicine. 2005.
  • "Practice Parameters: Determining Brain Death in Adults." American Academy of Neurology. 1994. (Aug. 12, 2008)
  • "The Top Ten Causes of Death." World Health Organization. November 2008. (Dec. 16, 2008)
  • Tobin, Daniel R. "Peaceful Dying." Perseus Books. 1999.
  • University of Bath. "Call for Closer Examination of 'Brain Death' As The End of Life." ScienceDaily. Sept. 12, 2007. (Aug. 12, 2008)­ /releases/2007/09/070911202516.htm