CHAPTER 17
YOU ARE GOING TO DIE. Not a very cheerful prospect. But remember, science does not shirk from any topic. Every year, around 30,000 people die in Ireland1. This keeps the undertakers busy. They see a lot of dead people. Some die ahead of their natural lifespan because of an accident. Some make it to a ripe old age. We fill our lives with a busy schedule, but if you look at the calendar on your smartphone there will definitely be a date in the future on which you will die. Go on, scroll down through the dates into the future … you will pass a date on which you are going to die. The Grim Reaper just hasn’t filled that date in yet.
What’s interesting is that a child born in Ireland today can reasonably expect to live to be over 100. This is because of advances in modern medicine, with medicines like statins (which keep cholesterol in check in our bloodstream and therefore decrease the risk of heart attack), and hopefully better lifestyles (not smoking, eating less, exercising more and getting plenty of sleep) improving lifespan for all. However, around 20 per cent of people will die in a sudden or unexpected way – an accident or a stroke, perhaps. A further 20 per cent will die of cancer (although those numbers will improve, with new treatments continuing to emerge, as we saw in Chapter 14).
Those with cancer will stay relatively healthy until quite close to death, when there is usually a linear deterioration over a few weeks. The rest of us will undergo a slow deterioration as we age, suffering from various chronic medical problems such as heart or kidney failure, or dementia, buoyed by a range of medicines to keep us going longer2. By some estimates, more than 90 per cent of the medicines you will take will be taken in your last year of life. Your final months will be characterised by a series of relapses and remissions against a backdrop of slow deterioration in physical function. Pretty grim, huh? So eat, drink and be merry, for tomorrow (or whenever) we die.
EAT, DRINK AND BE MERRY … FOR TOMORROW WE DIE
One thing about death that has preoccupied people for hundreds of years is how we actually know someone is dead. It may seem obvious now, but in the past it wasn’t (unless of course someone had their head chopped off). Say you lived a few hundred years ago and old Grandpa (who back then was probably 40 years of age) seemed to have croaked. You didn’t call for a doctor, you called for the priest, who would make the determination of death. All the priest would have at his (never her) disposal would be outward signs of death. They might hold a mirror over Grandpa’s mouth to see if it clouded over. Or a feather under his nose to see if it moved. In the 1700s enough was known about the human body to check for his heartbeat. The stethoscope, though, wasn’t invented until 1816 by the French physician René Laennec. The binaural stethoscope (on which modern stethoscopes are based) was invented by Irish physician Arthur Leared. There was a rather gruesome procedure known as Balfour’s test, where long thin needles were stuck into a person’s heart and then left protruding with small flags attached. If the flags moved, the heart was beating and the person was deemed to be alive.
However, doctors began to realise that, although outwardly the person appeared to be dead (with no detectable heartbeat or breathing), they might in fact be still alive and perhaps might recover. This phenomenon led to people being buried alive, which wasn’t especially unusual in the 19th century. Edgar Allan Poe (who according to John Lennon often got a kicking) made great mileage from such horror stories. To provide a safeguard, some coffins had a string from the inside up to the ground attached to a bell, which the unfortunate person could ring should they awake in their coffin – a dead (or actually live) ringer. Even today, doctors are cautious when pronouncing people dead under certain circumstances. When a patient is brought to a hospital comatose from, for example, attempted suicide or drowning, they may well have no signs of life. Their bodies, which will be cold to the touch, are usually warmed up first to check that they are actually dead, as signs of life might well return. The term ‘warm and dead’ is used for these unfortunate people.
Nowadays there are all kinds of ways to attempt to resuscitate someone, or keep them alive. A person can be hooked up to a ventilator, to maintain breathing and to keep blood circulating. There are a whole host of devices that can keep a person alive if you just measure their pulse as the indicator of being alive. But in the 1950s doctors recognised that people were being kept ‘alive’ by machines. The phrases ‘persistent vegetative state’ and ‘irreversible coma’ were invented to describe these people. They weren’t coming back, because of brain damage that couldn’t be repaired. We therefore now define death as being ‘brain dead’.
A person who meets this whole-brain definition of death has lost the ability to breathe on their own. Breathing is essential to providing the oxygen your body needs to burn fuel in order to provide the necessary energy to keep the lights on. Simply put, dying starts when the body doesn’t get enough oxygen to survive. Different cells in your body die at different speeds, however. If you cut yourself and your blood spills on the floor, that blood is full of white blood cells, which will continue to live for a few hours outside your body. The length of the dying process actually depends on which cells are deprived of oxygen.
The brain is especially greedy in this regard. It needs a lot of fuel to keep running. All those neurons crackling away burn 75 per cent of the glucose you consume, and need oxygen to do it. Any cut-off in oxygen to the brain (as happens in a massive stroke, which blocks the main blood vessel in the brain – the middle cerebral artery) will kill you within three to seven minutes. Cyanide kills in a similarly rapid fashion, because it directly interferes with the process of respiration (where oxygen is used to burn fuel to make the energy currency of cells – ATP). Similarly, if you cut off the blood supply to the heart by blocking, say, the main coronary artery, death will happen relatively quickly, as the heart goes into spasm.
A COFFIN BELL – YOUR SAFEGUARD AGAINST BEING BURIED ALIVE.
For most, though, these sudden deaths won’t be the way you die. Your body’s systems will simply break down with time, as we saw in the chapter on ageing. Like all machines, the component parts simply wear out. As death approaches, there will be some outward signs that these systems are slowly failing, and that the Grim Reaper is knocking on the door (or the banshee howling up on the roof). The person will sleep more to conserve whatever energy they have left, a bit like sleep mode on your computer. When energy reserves are very low, you won’t have the energy to eat and drink. Swallowing will become difficult and your mouth will become very dry. Any pain you might feel can usually be managed by a doctor. Many people in fact shuffle off this mortal coil blissed out on a morphine-type sedative, falling almost literally into the arms of Morpheus. Not a bad way to go.
When someone is dying, that brings us into the realm of palliative care. The goal of palliative care is to improve a person’s comfort and quality of life rather than trying to extend it per se. This can be a challenge for the medical professional, who will sometimes try their best to extend life. This is an important area, since, as the writer Cicely Saunders has said, ‘How we die remains in the memory of those who live on.’
One disconcerting aspect of dying which grieving relatives might hear is known as the ‘death rattle’. This happens when fluid builds up in the lungs, and the resulting congestion makes a noise as the person breathes their last breaths. Then, your heart stops, and that’s that. All those heartbeats, which began in your mother’s womb when you were developing, not stopping year after year after year, totalling on average over 2 billion – a remarkable piece of bioengineering, but like all good things, it has to come to an end.
One thing we don’t know is what exactly a dying person is feeling. However, some people have come back from death’s door and reported a feeling of peace and well-being3. These are called near-death experiences (or NDEs in the trade), and there is a remarkable commonality in what people report. Some report an out-of-body experience, a feeling of floating above their own body. Some report seeing a bright light and moving towards it. Some even say they see dead relatives beckoning them. These things are remarkably common across all cultures.
One explanation for the bright light is the last firing of the optic nerves. The most likely explanation for the other responses is brain changes, which lead to hallucination. They may be caused by the body making its own endorphins, the natural painkillers, released normally when we are in pain, or after strenuous exercise. They will act as a sedative to ease pain, and may give rise to a dream-like state. Others of course interpret these things in a spiritual way. The process lets others know that death is nothing to be frightened of. And indeed so it seems. People close to death in general are not anxious about dying, perhaps because endorphins start to kick in as the death process begins.
Eventually, a point of no return is reached, which is termed ‘biological death’. After your heart stops beating, the brain cells will begin to die because of a lack of oxygen. Once this happens, any resuscitation is impossible. Death can play one last trick, though. The Lazarus sign refers to a rare spinal reflex that can happen in the newly deceased. Neurons in the spinal cord are not yet dead and trigger a reflex. The person’s arms rise up and cross over each other on their chest before falling back down. This dramatic event is sure to make the medical team or unfortunate relatives jump.
Once death has occurred, what you think has happened to the essence of the person who has died will depend on your religious or cultural beliefs. The loss of a loved one might mean people are comforted by the notion of seeing that person again in some kind of afterlife. But without doubt, death fascinates us all. A scientific question that has come to the fore of late is, Can you predict at what age you might die? Governments and actuaries in insurance companies like to do these kinds of calculations, as they allow them to figure out how much to charge to cover pensions, and how much healthcare people might need as they grow old.
There are online questionnaires you can fill in for which you provide information on your weight, bad habits, family history of illness and the like, and they will spit out a possible date when you might expect to die. Then there is the ‘Death Clock’, which predicts the chances of a healthy person dying from any medical condition in the next five years4. I just did it on myself and it told me that I will die when I’m 78 years, three months and 14 days of age. It has given me 219,012 hours, 17 minutes and 21 seconds to live, and it’s counting down; I must mark the date in my diary immediately: 1 October 2042 – gulp!
Scientists were surprised to find that an easy blood test was able to predict if a person was likely to die even if they were not ill5. Levels of four specific factors in the blood taken together gave a measure of how ‘frail’ you might be. If these so-called biomarkers were sufficiently different from the average, the person was five times more likely to die within five years. What was interesting was these markers gave an indication of dying not from something specific like heart disease, but instead were signs of general well-being. Biomarkers include things like cholesterol levels, which will give a prediction of your chance of having a heart attack.
But these biomarkers were different, and comprised four biochemicals: albumin, alpha-1-acid glycoprotein, citrate and the size of very low-density lipoproteins, particles that occur in the blood. Blood was taken from 17,000 generally healthy people, and more than 100 biomarkers were examined. These four were the ones that gave the best association with likelihood of dying – 684 people died, and it was in these people that the four biomarkers were most out of kilter. One in five people with the highest level died within one year.
This study was actually an excellent example of science in action. The findings were first made in 9,842 people in Estonia, but the scientists didn’t quite believe the result, and so examined another 7,503 people in Finland and got the same trend. The effect therefore was reproducible and likely to be universal. When a discovery is made it must be reproduced to ensure it’s accurate. The analysis of these four biomarkers might become a widely used test, which might predict people at a higher risk of dying and so might need medical intervention.
Ethics comes into play, however. Remember, these are generally healthy people. Would the scientists have to tell the people that they are at a high risk of dying within a year? Would the people want to know? How would it affect their behaviour? Would they immediately draw up a bucket list, leave their families and go on a hedonistic trip around the world? Who knows? Maybe we all need a licence to enjoy the time we have on Earth, and maybe a test like this might help us, but remember, it only gives our risk of dying, not absolute certainty. And some will have elevated biomarkers and not die.
So once you’re dead what happens next? Well, it’s about to get much more gruesome, so those of a fragile disposition might make sure the lights are on, and that you have a stiff drink in hand. But again, as scientists we shirk at nothing. Once you are dead, the second law of thermodynamics kicks in. This law says that things will always become more random, or to put it more scientifically, everything tends towards an increase in entropy. In this case, the body decomposes6. It breaks down into its component parts (which in that state will have increased entropy – a bit like a gas with the molecules all moving randomly).
One definition of life is ‘a defiance of entropy’: your body maintains itself in a highly ordered state (as in all your structures – bones, organs and tissues – are intact when you’re alive, via the input of energy in the form of the food you eat). Once that energy drains away, the second law does its remorseless job and you start to decay. How long that takes will depend on where your body is. If you are refrigerated everything is slowed down, since molecules move much more slowly when they are cold. Decay will take some time to happen, as we know when we put meat in the fridge. If you are encased in a lead-lined coffin, it can take decades to completely decompose. But if left out in the open or buried in soil, the body will disappear in a few months.
Let’s look at the sequence of events. These have been mapped out by forensic scientists who try and establish time of death. Within minutes of death, carbon dioxide starts to build up in your bloodstream. This is because you normally breathe this out – it’s part of the exhaust that comes off from the burning of food in your body, to release energy. This gas, however, is quite toxic to cells, which start to burst open. Cells have proteins in them that digest things (for example the food they eat), and so these get to work on digesting you. Your tissues begin to get chewed up from within.
After 30 minutes or so, your blood (which has stopped circulating because your heart is no longer beating) will start to pool at the lowest point. This can mean a corpse can turn black on its underside because of the pooled blood, while the rest of the body goes very pale. Calcium begins to leach out of your muscle cells, and this means they contract. This is called rigor mortis – a well-known stiffening of the body. A dear friend of mine who himself has sadly passed, Stephen Connelly, used to refer to an erection as a ‘Rigorous Mortimer’, but this is something quite different.
The next big event is your guts burst, again because of a gaseous build-up. This releases all the billions of bacteria from your gut, which help with more digestion but also give rise to the unpleasant odour of a rotting corpse. The bacteria also produce gases that bloat the body and build up over the course of about two weeks. This is when drowned people surface and get washed ashore.
Gradually more bacteria move in, as do a whole host of creatures. The first insects to arrive are flies, including houseflies. Different species of flies arrive at different times, and this is highly informative for the forensic pathologist. There is in fact a specialism within forensics – forensic entomology7 – that studies this aspect: which insects appear on a corpse when, and which maggots grow first. This is a wonderful topic to discuss at a dinner party. Some flies prefer a body that is much riper than others. Beetles tend to arrive latest to the party, as they prefer a well-decomposed body. The flies lay eggs and maggots will soon appear to give rise to more flies, and so the cycle continues.
Eventually, after a period of months (or years, depending on the climate and where the body is), all that is left is bones. Even the collagen in the bones, which is especially tough, will be broken down. No creatures can digest bone, which is a hard, calcium-based mineral. Sometimes, though, the bones will crumble and turn to dust and be blown away. Your body has now been fully recycled and gone back to the stardust whence it came. In the immortal words of David Bowie: ashes to ashes, funk to funky.
Estimating the time of death is actually a very precise science. The first thing that is done is to see if the dead person is wearing a watch to see if it’s stopped because of being broken. Pretty obvious, huh? There are in fact three times of death: the biological time of death (which is when the person actually died), the estimated time of death (which should be the same as the biological time of death but might be slightly off) and finally the legal time of death, which is entered on your death certificate. This is when the body was discovered or pronounced dead by another individual. One method that is used to estimate the time of death is to measure the body temperature. When you’re alive, your core body temperature is 37.5°C. After death your body will cool by 1.5°C per hour until you reach room temperature.
FORENSIC ENTOMOLOGY CAN DATE A CORPSE FROM THE INSECTS AND WORMS PRESENT AT DIFFERENT TIMES AFTER DEATH.
Another method that is used is called LABRADOR8, which stands for ‘Lightweight Analyser for Buried Remains and Decomposition Odour Recognition’. It’s a cutesy name (that must have taken some time to come up with) for a rather unpleasant device that ‘sniffs’ the various chemicals released by decaying bodies. The odours come from chemicals being released by different species of bacteria. Like insects, different species arrive at different times, and this means different odours being produced. This study is carried out at what can only be described as possibly the most gruesome place for science – the Human Decomposition Research Laboratory in Huntsville, Texas. This site contains donated cadavers which are left to decompose at various locations on the seven-acre site. The scientists found that specific populations of ‘decomposer’ bacteria, microbes on the skin of the corpses but also in the soil under them, gave an accurate prediction of time of death. One fascinating finding was that the microbial composition of the soil under the body changes dramatically, acting as a signature that a dead body was there. This could prove that a body has been moved after death, which might become relevant in murder trials.
EVERY HOME SHOULD HAVE A LIGHTWEIGHT ANALYSER FOR BURIED REMAINS AND DECOMPOSITION ODOUR RECOGNITION – OR LABRADOR FOR SHORT. IT DETECTS THE VARIOUS CHEMICALS RELEASED BY DECAYING BODIES TO CALCULATE TIME OF DEATH.
Finally, to further emphasise what a hot topic of research this is, a recent breakthrough that might provide a very accurate time of death is to measure the expression of genes. Surprisingly, even though you’re dead, some of your cells are still alive and are making proteins – some of their genes are still active9. This was first shown in mice and zebra fish, but also probably occurs in humans. They measured mRNA (the first product of a gene, which then becomes a protein) in brain and liver samples from mice and zebra fish up to four days after death.
As expected, many mRNAs are decreased as a cell switches off. However, mRNA for 548 zebra fish genes and 515 mouse genes saw one or more peaks of activity after death. This means that the cells had sufficient energy to crank out at least some proteins. What was especially interesting was that some genes ‘woke up’ after death. These were genes previously seen in the foetus, which was a surprise. Almost as if there was a rebirth after death. Some of the genes are associated with growth and repair. It looks as if the body is trying to defy death. It wants to go back to being a foetus with its whole life ahead of it, or repair the damage that has happened and restore the body back to normal.
It could also be that these genes are normally kept in check by genes that are being turned off after the death of the cell. Whatever the reason, because these genes are switched on and off at specific times, it might be possible to time death very precisely based on gene expression changes. It might even be possible to get the time of death down to a level of accuracy that is in the order of minutes. What is intriguing here is that we have life in the face of death.
And so your life is top and tailed – your birth cert recording when you were born, and your death cert recording when you died, perhaps to the very minute. With your life, with all its ups and downs and ins and outs, in between those two dates. Food for worms at last. Make of this what you will.