To help us deal better with this fractional lag, the brain does a truly extraordinary thing: it continuously forecasts what the world will be like a fifth of a second from now, and that is what it gives us as the present. That means that we never see the world as it is at this very instant, but rather as it will be a fraction of a moment in the future.
His most notorious failure was Rosemary Kennedy, sister of the future president. In 1941, she was twenty-three years old, a vivacious and attractive girl but headstrong and with a tendency to mood swings. She also had some learning difficulties, though these seem not to have been nearly as severe and disabling as has sometimes been reported. Her father, exasperated by her willfulness, had her lobotomized by Freeman without consulting his wife. The lobotomy essentially destroyed Rosemary. She spent the next sixty-four years in a care home in the Midwest, unable to speak, incontinent, and bereft of personality.
As recently as 1956, it was illegal in seventeen U.S. states for epileptics to marry; in eighteen states, epileptics could be involuntarily sterilized. The last of these laws was repealed only in 1980.
Anton-Babinski syndrome, for instance, is a condition in which people are blind but refuse to believe it. In Riddoch syndrome, victims cannot see objects unless they are in motion. Capgras syndrome is a condition in which sufferers become convinced that those close to them are impostors. In Klüver-Bucy syndrome, the victims develop an urge to eat and fornicate indiscriminately (to the understandable dismay of loved ones). Perhaps the most bizarre of all is Cotard delusion, in which the sufferer believes he is dead and cannot be convinced otherwise.
In 1997, Adrian Owen, then a young neuroscientist working in Cambridge, England, discovered that some people thought to be in a vegetative state are in fact fully aware but powerless to indicate the fact to anyone. In his book Into the Gray Zone, Owen discusses the case of a patient named Amy who suffered a serious head injury in a fall and for years lay in a hospital bed. Using an fMRI scanner, and carefully watching the woman’s neural responses when researchers asked her a series of questions, they were able to determine that she was fully conscious.
(S)mile involves the contraction of the orbicularis oculi muscle in each eye, and we have no independent control over those muscles.
The ossicles are perfect demonstrations of how evolution is so often a matter of make-do. They were jawbones in our ancient ancestors and only gradually migrated to new positions in our inner ear. For much of their history, those three bones had nothing to do with hearing.
Volume doubles about every 6 decibels, which means that a 96-decibel noise is not just a bit louder than a 90-decibel noise but twice as loud. The pain threshold for noise is about 120 decibels, and noises above 150 decibels can burst the eardrum.
When we smell something, the information, for reasons unknown, goes straight to the olfactory cortex, which is nestled close to the hippocampus, where memories are shaped, and it is thought by some neuroscientists that that may explain why certain odors are so powerfully evocative of memories for us.
Uniquely among mammals, we send our air and food down the same tunnel. Only a small structure called the epiglottis, a kind of trapdoor for the throat, stands between us and catastrophe. The epiglottis opens when we breathe and closes when we swallow, sending food in one direction and air in another, but occasionally it errs and the results are sometimes dire.
The death rate from heart diseases has fallen from almost 600 per 100,000 in 1950 to just 168 per 100,000 today. As recently as 2000, it was 257.6 per 100,000. But it is still the leading cause of death.
All forms of heart failure can be cruelly sneaky. For about a quarter of victims, the first (and, more unfortunately, last) time they know they have a heart problem is when they suffer a fatal heart attack. No less appallingly, more than half of all first heart attacks (fatal or otherwise) occur in people who are fit and healthy and have no known obvious risks. They don’t smoke or drink to excess, are not seriously overweight, and do not have chronically high blood pressure or even bad cholesterol readings, but they get a heart attack anyway. Living a virtuous life doesn’t guarantee that you will escape heart problems; it just improves your chances.
Remarkably, even with all the improvements in care, you are 70 percent more likely to die from heart disease today than you were in 1900. That’s partly because other things used to kill people first, and partly because a hundred years ago people didn’t spend five or six hours an evening in front of a television with a big spoon and a tub of ice cream. Heart disease is far and away the Western world’s number one killer.
The pituitary gland, for instance, which is buried deep within your brain directly behind your eyes, is only about the size of a baked bean, yet its effects can be—literally—enormous. Robert Wadlow of Alton, Illinois, the tallest human who ever lived to that point, had a pituitary condition that caused him to grow ceaselessly because of continuous overproduction of growth hormone. A shy and cheerful soul, he was taller than his (normal-sized) father by the age of eight, was 6 feet 11 inches tall at the age of twelve, and over 8 feet tall when he graduated from high school in 1936—all because of a little chemical overexertion by this baked bean in the middle of his skull. He never stopped growing and was just a fraction under 9 feet tall at his greatest eminence. Though not fat, he weighed about five hundred pounds. His shoes were a size 40. By his early twenties, he could walk only with great difficulty.
The pituitary is often called the master gland because it controls so much. It produces (or regulates the production of) growth hormone, cortisol, estrogen and testosterone, oxytocin, adrenaline, and much else. When you exercise vigorously, the pituitary squirts endorphins into your bloodstream. Endorphins are the same chemicals released when you eat or have sex. They are closely related to opiates. That’s why it is called the runner’s high. There is barely a corner of your life that the pituitary doesn’t touch, yet its functions weren’t even broadly understood until well into the twentieth century.
Addison’s disease is a rare but still-serious illness. It affects about one person in ten thousand. History’s most famous sufferer was John F. Kennedy, who was diagnosed with it in 1947, though he and his family always emphatically and untruthfully denied it. In fact, Kennedy not only had Addison’s but was lucky to survive it.
One area where testosterone appears not to be doing us men any good at all is longevity. Many factors determine life span, of course, but it is a fact that men who have been castrated live about as long as women do. In what way exactly testosterone might shorten male lives is not known.
Testosterone levels in men fall by about 1 percent a year beginning in their forties, prompting many to take supplements in the hope of boosting their sex drive and energy levels. The evidence that it improves sexual performance or general virility is thin at best; there is much greater evidence that it can lead to an increased risk of heart attack or stroke.
The liver is a gland and it is, compared with the rest of our glands, gigantic. When fully grown, it weighs about 3.3 pounds, roughly the same as the brain, and fills much of the central abdomen just below the diaphragm. It is disproportionately large in infants, which is why their bellies are so delightfully rounded.
Perhaps the most wondrous feature of the liver is its capacity to regenerate. You can remove two-thirds of a liver and it will grow back to its original size in just a few weeks.
The humors were believed to be fluids that circulated within the body and kept everything in balance. For two thousand years, a belief in humors was used to explain people’s health, looks, tastes, disposition—everything. In this context, humor has nothing to do with amusement. It comes from a Latin word for “moisture.” When we talk today of humoring someone or of people being ill-humored, we are not talking about their capacity for laughter, at least not etymologically.
Cartilage is remarkable, too. It is many times smoother than glass: it has a friction coefficient five times less than ice. Imagine playing ice hockey on a surface so smooth that the skaters went sixteen times as fast. That’s cartilage. But unlike ice, it isn’t brittle. It doesn’t crack under pressure as ice would. And you grow it yourself. It’s a living thing.
We tend to think of our bones as inert bits of scaffolding, but they are living tissue, too. They grow bigger with exercise and use just as muscles do. “The bone in a professional tennis player’s serving arm may be 30 percent thicker than in his other arm,” Margy Pratten told me, and cited Rafael Nadal as an example. Look at bone through a microscope and you will see an intricate array of productive cells just as in any other living thing. Because of the way they are constructed, bones are, to an extraordinary degree, both strong and light.
Out of some 250 species of primates, we are the only ones that have elected to get up and move around exclusively on two legs. Some authorities think bipedalism is at least as important a defining characteristic of what it is to be human as our high-functioning brain.
Perhaps no statistic to do with our increasing mass is more telling than that the average woman in the United States today weighs as much as the average man weighed in 1960.
One area where animals are curiously—almost eerily—uniform is with the number of heartbeats they have in a lifetime. Despite the vast differences in heart rates, nearly all animals have about 800 million heartbeats in them if they live an average life. The exception is humans. We pass 800 million heartbeats after twenty-five years, and just keep on going for another fifty years...1.6 billion heartbeats or so. It is tempting to attribute this exceptional vigor to some innate superiority on our part, but in fact it is only over the last ten or twelve generations that we have deviated from the standard mammalian pattern thanks to improvements in our life expectancy. For most of our history, 800 million beats per lifetime was about the human average, too.
In one well-known experiment cited by the British academic Steve Jones, a test subject ran a marathon on a treadmill while the room temperature was gradually raised from minus 49 degrees Fahrenheit to 131 degrees Fahrenheit—roughly the limits of human tolerance at both extremes. Despite the subject’s exertions and the great range of temperatures, his core body temperature deviated by less than one degree over the course of the exercise.
What is less well known is that the same thing applies, albeit on a different scale, to small humans. A child half your height who falls and strikes her head will experience only one thirty-second the force of impact that a grown person would feel, which is part of the reason that children so often seem to be mercifully indestructible.
Even with the advantage of clothing, shelter, and boundless ingenuity, humans can manage to live on only about 12 percent of Earth’s land area and just 4 percent of the total surface area if you include the seas. It is a sobering thought that 96 percent of our planet is off-limits to us.
For reasons of economy, airlines normally keep cabins pressurized to an altitude equivalent of forty-nine hundred feet to seventy-nine hundred feet, which is why alcohol is more likely to go to your head while flying. It also accounts for why your ears pop during descent because the pressure changes as you reduce elevation. On an airliner flying at a normal cruising altitude of thirty-five thousand feet, if the cabin suddenly depressurized, passengers and crew could become confused and incompetent in as little as eight or ten seconds.
Under a doctor named Shiro Ishii, the Japanese built an enormous complex of more than 150 buildings spread over almost 1,500 acres at Harbin in Manchuria with the avowed purpose of determining human physiological limitations through any means necessary. The facility was known as Unit 731.
The largest and in many ways most mystifying and intractable category of immune disorders is allergies. An allergy is simply an inappropriate response by the body to a normally harmless invader.
Cancers have learned to exploit this by sending out stop signals of their own, fooling the immune system into retiring prematurely. Checkpoint therapy simply overrides the stop signals. The therapy works miraculously well with some cancers—some people with advanced melanomas who were near death have staged complete recoveries—but for reasons still not well understood, it only works sometimes. It also can have serious side effects.
“All we can really say about asthma is that it is primarily a Western disease,” says Pearce. “There is something about having a Western lifestyle that sets up your immune system in a way that makes you more susceptible. We don’t really understand why.”
Some years ago, Pearce made a curious discovery—that people who had had a cat early in life seemed to derive lifelong protection from getting asthma. “I like to joke that I’ve studied asthma for thirty years and I have never prevented a single case, but I have saved the lives of a lot of cats,” he says.
The problem was that huge proportions of people smoked—80 percent of all men by the late 1940s—yet only some of them developed lung cancer.
Today just 18 percent of Americans smoke, and it is easy to think that we have pretty much solved the problem. But it’s not quite as simple as that. Nearly one-third of people below the poverty line still smoke, and the habit continues to account for one-fifth of all deaths. It is a problem we are a long way from rectifying.
A hiccup is a sudden spasmodic contraction of the diaphragm, which essentially startles the larynx into closing abruptly, making the famous hic sound. No one knows why they happen.
Until 1964, the official guidance in the United States was for thirty-two hundred calories per day for a moderately active man and twenty-three hundred for a similarly disposed woman. Today those inputs have been reduced to about twenty-six hundred calories for a moderately active man and two thousand for a moderately active woman.
We are incapable of deriving nutrition from most parts of most plants. In particular we cannot make use of cellulose, which is what plants primarily consist of. The few plants that we can eat are the ones we know as vegetables. Otherwise we are limited to eating a few botanical end products, such as seeds and fruits, and even many of those are poisonous to us. But we can benefit from a lot more foods by cooking them.
Vitamins are simply organic chemicals—that is, from things that are or were once alive, like plants and animals—while minerals are inorganic and come from soil or water. Altogether there are about forty of these little particles that we must get from our foods because we cannot manufacture them for ourselves.
According to the Centers for Disease Control, far from having plenty in our diet, some 90 percent of American adults don’t get the recommended daily dose of vitamins D and E and about half don’t get sufficient vitamin A. No less than 97 percent, according to the CDC, don’t get enough potassium, a vital electrolyte, which is particularly alarming because potassium helps to keep your heart beating smoothly and your blood pressure within tolerable limits.
All that can be said is that a small but unspecified number of amino acids strung together is a peptide. Ten or twelve strung together is a polypeptide. When a polypeptide begins to get bigger than that, it becomes, at some ineffable point, a protein.
CARBOHYDRATES ARE COMPOUNDS of carbon, hydrogen, and oxygen, which are bound together to form a variety of sugars—glucose, galactose, fructose, maltose, sucrose, deoxyribose (the stuff found in DNA), and so on.
THE THIRD MEMBER of the trio, fats, are also made up of carbon, hydrogen, and oxygen, but in different proportions. This has the effect of making fat easier to store.
In 2007, a young woman in California named Jennifer Strange died after drinking six quarts of water in three hours in a clearly ill-judged water-drinking competition held by a local radio station. Similarly in 2014, a high school football player in Georgia, complaining of cramps after practice, downed two gallons of water and two of Gatorade and soon afterward fell into a coma and died.
In 1915, the average American spent half his weekly income on food. Today it’s just 6 percent. We live in a paradoxical situation. For centuries, people ate unhealthily out of economic necessity. Now we do it out of choice.
Altogether about 80 percent of the processed foods we eat contain added sugars. Heinz ketchup is almost one-quarter sugar. It has more sugar per unit of volume than Coca-Cola.
It is hard to know what to make of any of this. According to the Statistical Abstract of the United States, the amount of vegetables eaten by the average American between 2000 and 2010 dropped by thirty pounds. That seems an alarming decline until you realize that the most popular vegetable in America by a very wide margin is the French fry. (It accounts for a quarter of our entire vegetable intake.) These days, eating thirty pounds less “vegetables” may well be a sign of an improved diet.
He found nineteen different kinds of microorganisms there, which was considerably more than he expected to find because the only obvious sources of input were their mothers’ milk and the air they breathed. The most abundant of these is called Escherichia coli in his honor. (Escherich himself called it Bacteria coli commune.) E. coli has become the most studied microbe on the planet. It has spawned literally hundreds of thousands of papers, according to Carl Zimmer, who has written a fascinating book, Microcosm, on this single extraordinary bacillus.
All the gases of flatus can make a pretty explosive combination, as was tragically demonstrated in Nancy, France, in 1978 when surgeons stuck an electrically heated wire up the rectum of a sixty-nine-year-old man to cauterize a polyp and caused an explosion that literally tore the patient apart. According to the journal Gastroenterology, this was just one of “many recorded examples of explosion of colonic gas during anal surgery.”
It comes as a surprise to most of us, but hibernation and sleep are not the same thing at all, at least not from a neurological and metabolic perspective. Hibernating is more like being concussed or anesthetized: the subject is unconscious but not actually asleep. So a hibernating animal needs to get a few hours of conventional sleep each day within the larger unconsciousness.
The amount of sleep needed varies markedly among animals. Elephants and horses get by on just two or three hours a night. Why they need so little is unknown. Most other mammals require a great deal more. The animal that used to be thought the mammalian sleep champion, the three-toed sloth, is still often said to sleep for up to twenty hours a day, but that number came from studying captive sloths, who have no predators and not a lot to do. Wild sloths slumber for more like ten hours a day—not a huge amount more than we do.
Most men have erections during REM sleep. Women likewise experience increased blood flow to the genitals. No one knows why, but it seems not to be overtly associated with erotic impulses. Typically, a man will be erect for two hours or so a night.
In recent years, Foster and his colleagues have come to realize that we have more seasonal rhythms than formerly thought. “We’ve been finding rhythms,” he says, “in lots of unexpected areas—self-harm, suicide, child abuse. We know it is not just coincidental that these things have seasonal peaks and troughs because the patterns are six-month-shifted from the Northern Hemisphere to the Southern.” Whatever people do in a northern spring—like commit suicide in greater numbers—they do six months later in the southern spring.
Nearly all authorities agree that we are sleeping less than we used to at all age levels. According to the journal Baylor University Medical Center Proceedings, the average amount of sleep people get on a night before work has fallen from eight and a half hours fifty years ago to under seven now. Another study found a similar decline among schoolchildren. The cost to the U.S. economy of all this tossing and turning has been estimated at more than $60 billion from absenteeism and diminished performance.
About half of us snore at least sometimes. Snoring is the rattling of the soft tissues in the pharynx when one is unconscious and relaxed. The more relaxed, the greater the snoring, which is why drunken people snore particularly robustly. The best way to reduce snoring is to lose weight, sleep on your side, and not drink alcohol before retiring.
In fatal familial insomnia, prions attack the thalamus, the walnut-sized body deep in the brain that controls our autonomic responses—blood pressure, heart rate, the release of hormones, and so on.
The longest anyone has intentionally gone without sleep was in December 1963 when a seventeen-year-old high school student in San Diego named Randy Gardner managed to stay awake for 264.4 hours (11 days and 24 minutes) as part of a school science project. The first few days were comparatively easy for him, but gradually he became irritable and confused until his entire existence was a kind of hallucinatory blur. When he finished the project, Gardner fell into bed and slept for 14 hours. “I remember when I woke up, I was groggy, but not any groggier than a normal person,” he told an NPR interviewer in 2017.
We now know, of course, that females have two X chromosomes and males have one X and a Y, which is what accounts for their sexual differences, but that knowledge was a long time in coming. Even in the late nineteenth century, scientists commonly thought that sex was determined not by chemistry but by external factors like diet or air temperature or even a woman’s mood during the early stages of pregnancy.
Interestingly, sex isn’t actually necessary. Quite a number of organisms have abandoned it. Geckos, the little green lizards that are often encountered clinging like suckered bath toys to walls in the tropics, have done away with males altogether. It is a slightly unsettling thought if you are a man, but what we bring to the procreative party is easily dispensed with. Geckos produce eggs, which are clones of the mother, and these grow into a new generation of geckos. From the mother’s point of view, this is an excellent arrangement because it means that 100 percent of her genes are inherited.
If genetic immortality is your ambition, then sex is a very poor way of achieving it. As Siddhartha Mukherjee observed in The Gene: An Intimate History, humans don’t actually reproduce at all. Geckos reproduce; we recombine.
On a more positive note, we can say with some confidence that the median time for sex (in Britain at least) is nine minutes, though the whole act, including foreplay and undressing, is more like twenty-five minutes. According to Spiegelhalter, energy use on average per sexual session is about a hundred calories for men and about seventy for women.
Far more significantly, women and men have heart attacks in quite different ways. A woman suffering a heart attack is more likely to experience abdominal pain and nausea than a man, which makes it more probable that it will be misdiagnosed. In a thousand ways large and small, they are quite different beings.
Women are anatomically different in one other very significant way: they are the sacred keepers of human mitochondria—the vital little powerhouses of our cells. Sperm pass on none of their mitochondria during conception, so all mitochondrial information is transferred from generation to generation through mothers alone.
Consider the G spot. It is named for Ernst Gräfenberg, a German gynecologist and scientist who fled Nazi Germany for America and there developed the intrauterine contraceptive device, which was originally called the Gräfenberg ring. In 1944, he wrote an article for the Western Journal of Surgery, Obstetrics and Gynecology in which he identified an erogenous spot on the wall of the vagina.
The vulva is the complete genital package—vaginal opening, labia, clitoris, and so on. The fleshy mound above the vulva is called the mons pubis. At the top of the vulva itself is the clitoris (probably from a Greek word for “hillock,” but there are other candidates), which is packed with some eight thousand nerve endings—more per unit of area than any other part of the female anatomy—and exists, as far as can be told, only to give pleasure. Most people, including females, are unaware that the visible part of the clitoris, called the glans, is literally only the tip of it. The rest of the clitoris plunges into the interior and extends down both sides of the vagina for about five inches. Until the early twentieth century, “clitoris” seems generally to have been pronounced “kly-to-rus.”
The uterus is simply a more formal name for the womb, where babies grow. The uterus normally weighs two ounces, but at the end of a pregnancy it may weigh two pounds.
Several studies have reported serious falls in sperm counts in recent decades. A meta-analysis in the journal Human Reproduction Update, based on 185 studies over nearly forty years, concluded that sperm counts in Western nations fell by more than 50 percent between 1973 and 2011.
It is a curious fact that every woman is born with her lifetime’s supply of eggs already inside her. They are formed when she is still in the womb and sit in the ovaries for years and years before being called into play. As noted in the previous chapter, the idea of women being born with a full load of eggs—the formal name is ova—was first suggested by the great and busy German anatomist Heinrich von Waldeyer-Hartz,
A twenty-week-old fetus will weigh no more than three or four ounces but will already have 6 million eggs inside her. That number falls to 1 million by the time of birth and continues to fall, though at a slower rate, through life. As she enters her childbearing years, a woman will have about 180,000 eggs primed and ready to go.
The age of first menstruation for women has fallen from fifteen in the late nineteenth century to just twelve and a half today, at least in the West. That is almost certainly because of improved nutrition. But what cannot be explained is that the rate has accelerated even further in more recent years. Just since 1980, the age of puberty has fallen in America by eighteen months. About 15 percent of girls now begin puberty by age seven. That could be a reason for alarm.
Success from this point is by no means assured. Perhaps as many as half of all conceptions are lost without being noticed. Without this, the rate of birth defects would be 12 percent instead of 2 percent. About 1 percent of implanted eggs end up stuck in the Fallopian tube, or somewhere else other than the womb, in what is known as an ectopic pregnancy (from a Greek word meaning “wrong place”). This can be very dangerous even now. Once it was a death sentence.
Into the 1930s, fewer than half of American women gave birth in hospitals. In Britain, it was closer to one in five. Today the proportion in both countries is 99 percent. It was the rise of penicillin, not improved hygiene, that finally conquered puerperal fever.
At all events, we now know, most miscarriages and other setbacks in pregnancy are because of problems with the placenta, not the fetus. Much of this is not well understood.
In simple terms, a baby’s head is too big for smooth passage through the birth canal, as any mother will freely attest. The average woman’s birth canal is about an inch narrower than the width of the average newborn’s head, making it the most painful inch in nature. To squeeze through this constricted space, the baby must execute an almost absurdly challenging ninety-degree turn as it proceeds through the pelvis. If ever there was an event that challenges the concept of intelligent design, it is the act of childbirth.
Various studies have found that people born by C-section have substantially increased risks for type 1 diabetes, asthma, celiac disease, and even obesity and an eightfold greater risk of developing allergies. Cesarean babies eventually acquire the same mix of microbes as those born vaginally—by a year their microbiota are usually indistinguishable—but there is something about those initial exposures that makes a long-term difference. No one has figured out quite why that should be.
As well as nurturing symbiotic bacteria, breast milk is full of antibodies. There is some evidence that a nursing mother absorbs a little of her suckling baby’s saliva through her breast ducts and that this is analyzed by her immune system, which adjusts the amount and types of antibodies she supplies to the baby, according to its needs. Isn’t life marvelous?
“For every organ, there is a critical period, often very brief, when it goes through development,” he said not long before his death in 2013. “It happens for different organs at different times. After birth only the liver and the brain and the immune system remain plastic. Everything else is done.” Most authorities now extend that period of crucial vulnerability from the moment of your conception to your second birthday—what has become known as the first thousand days. That means that what happens to you in this comparatively brief, formative period of your life can powerfully influence how comfortably alive you are decades later.
Opioid abuse remains for the most part a peculiarly American problem. The United States has 4 percent of the world’s population but consumes 80 percent of its opioids. About two million Americans are thought to be opioid addicts.
Take diphtheria. Into the 1920s, before the introduction of a vaccine, it struck down more than 200,000 people a year in America, killing 15,000 of them. Children were especially susceptible. It usually started with a mild temperature and a sore throat, so at first was easily mistaken for a cold, but it soon became much more serious as dead cells accumulated in the throat, forming a leathery coating (the term “diphtheria” comes from the Greek for “leather”; the disease, incidentally, is correctly pronounced “diff-theria,” not “dip-theria”) that made breathing increasingly difficult, and the disease spread through the body, shutting down organs one by one.
If you want to imagine what a disease might do if it became bad in every possible way, you could do no better than consider the case of smallpox. Smallpox is almost certainly the most devastating disease in the history of humankind. It infected nearly everyone who was exposed to it and killed about 30 percent of victims. The death toll in the twentieth century alone is thought to have been around 500 million.
With smallpox gone, tuberculosis is today the deadliest infectious disease on the planet. Between 1.5 and 2 million people die of it every year. It is another disease that we have mostly forgotten, but only a couple of generations ago it was devastating.
In the 2017–18 flu season, to take one recent example, people who had been vaccinated were only 36 percent less likely to get flu than those who hadn’t been vaccinated. In consequence, it was a bad year for flu in America, with a death toll estimated at eighty thousand.
Between 1900 and 1940, cancer jumped from eighth place to second place (just behind heart disease) as a cause of death, and it has cast a long shadow over our perceptions of mortality ever since. Today some 40 percent of us will discover we have cancer at some point in our lives. Many, many more will have it without knowing it and will die of something else first. Half of men over sixty and three-quarters over seventy, for instance, have prostate cancer at death without being aware of it. It has been suggested, in fact, that if all men lived long enough, they would all get prostate cancer.
We tend to think of cancer as something we catch, like a bacterial infection. In fact, cancer is entirely internal, a case of the body turning on itself. In 2000, a landmark paper in the journal Cell listed six attributes in particular that all cancer cells have, namely: They divide without limit. They grow without direction or influence from outside agents like hormones. They engage in angiogenesis, which is to say they trick the body into giving them a blood supply. They disregard any signals to stop growing. They fail to succumb to apoptosis, or programmed cell death. They metastasize, or spread to other parts of the body. What it comes down to really is cancer is, appallingly, your own body doing its best to kill you. It is suicide without permission.
It is almost impossible to imagine how horrifying this must have been. Two hundred years ago, every form of cancer was horrible, but breast cancer especially so. Most victims suffered years of torment and often unspeakable embarrassment as a tumor slowly devoured their breast and replaced it with an open hole from which seeped foul fluids that made it impossible for the poor victim to mix with others, sometimes even with her own family.
Radioactive products were liberally added to many medications, with sometimes devastating consequences. A popular over-the-counter painkiller called Radithor was made with diluted radium. An industrialist in Pittsburgh named Eben M. Byers treated it as a tonic and drank a bottle every day for three years until he discovered that the bones in his head were slowly softening and dissolving, like a stick of blackboard chalk left in the rain.
Although chemical weapons had been outlawed by international treaty after World War I, several nations still produced them, if only as a precaution in the event that others did likewise. The United States was among the transgressors. For obvious reasons, this was kept secret, but in 1943 a U.S. Navy supply ship, the SS John Harvey, carrying mustard gas bombs as part of its cargo, was caught in a German bombing raid on the Italian port of Bari. The Harvey was blown up, releasing a cloud of mustard gas over a wide area, killing an unknown number of people. Realizing that this was an excellent, if accidental, test of the mustard gas’s efficacy as a killing agent, the navy dispatched a chemical expert, Lieutenant Colonel Stewart Francis Alexander, to study the effects of the mustard gas on the ship’s crew and others nearby. Luckily for posterity, Alexander was an astute and diligent investigator, for he noticed something that might have been overlooked: mustard gas dramatically slowed the creation of white blood cells in those exposed to it. From this, it was realized that some derivative of mustard gas might be useful in treating some cancers. Thus was born chemotherapy.
The most heartening advance of recent times, however, is the striking improvement in mortality rates for the very young. In 1950, 216 children in every thousand—nearly a quarter—died before the age of five. Today the figure is just 38.9 early childhood deaths in a thousand—one-fifth what it was seventy years ago.
As Allan S. Detsky observed in The New Yorker, “Even wealthy Americans are not isolated from a lifestyle filled with oversized food portions, physical inactivity, and stress.” The average Dutch or Swedish citizen consumes about 20 percent fewer calories than the average American, for instance.
We have reached the decidedly bizarre point in health care in which pharmaceutical companies are producing drugs that do exactly what they are designed to do but without necessarily doing any good. A case in point is the drug atenolol, a beta-blocker designed to lower blood pressure, which has been widely prescribed since 1976. A study in 2004, involving a total of twenty-four thousand patients, found that atenolol did indeed reduce blood pressure but did not reduce heart attacks or fatalities compared with giving no treatment at all. People on atenolol expired at the same rate as everyone else, but, as one observer put it, “they just had better blood-pressure numbers when they died.”
We rarely know, for instance, what happens when various medications are taken in combination. One study found that 6.5 percent of hospital admissions in the U.K. were because of side effects from drugs, often taken in combination with other drugs.
IN 2011, AN interesting milestone in human history was passed. For the first time, more people globally died from non-communicable diseases like heart failure, stroke, and diabetes than from all infectious diseases combined. We live in an age in which we are killed, more often than not, by lifestyle.
After the age of sixty, the risk of death doubles every eight years. A study by geneticists at the University of Utah found that telomere length may account for as little as 4 percent of that additional risk. As the gerontologist Judith Campisi told Stat in 2017, “If all aging was due to telomeres, we would have solved the aging problem a long time ago.”
The sale of antioxidant supplements alone is now worth well over $2 billion a year. “It is a massive racket,” David Gems of University College London told Nature in 2015. “The reason the notion of oxidation and ageing hangs around is because it is perpetuated by people making money out of it.”
In the United States, there is the additional, rather extraordinary consideration that the Food and Drug Administration exercises practically no oversight on supplements. As long as supplements don’t contain any prescription medications and don’t obviously kill or seriously harm anybody, manufacturers can sell pretty much whatever they want, with “no guarantees of purity or potency, no established guidelines on dosage, and often no warnings about side effects that may result when the products are taken along with approved medications,” as an article in Scientific American noted. The products might be beneficial; it’s just that no one has to prove it.
Women are vividly reminded of the aging process when they reach menopause. Most animals die soon after they cease to be reproductive, but not (and thank goodness, of course) human females, who spend roughly a third of their lives in a postmenopausal state. We are the only primates that undergo menopause, and one of only a very few animals.
It is a myth, incidentally, that menopause is triggered by women exhausting their supply of eggs. They still have eggs. Not many, to be sure, but more than enough to remain fertile. So it isn’t the literal running out of eggs that triggers the process (as even many doctors appear to believe). No one knows exactly what is the trigger.
What can be said is that at present only about one person in ten thousand lives to be even a hundred. We don’t know much at all about people who live beyond that, partly because there aren’t many of them.
They also have longer telomeres. The theory is that they benefit from closer social bonds and family relationships. Curiously, it was found that if they live alone or don’t see a child at least once a week, the telomere length advantage vanishes.
Remarkably, the tissue samples Alzheimer took from Frau Deter survived and have been restudied using modern techniques, and it turns out that she was suffering from a genetic mutation unlike any ever seen in another Alzheimer’s patient. It appears that she might have been suffering not from Alzheimer’s at all but rather from another genetic condition known as metachromatic leukodystrophy. Alzheimer didn’t live long enough to fully understand the importance of his findings. He died from complications of a severe cold in 1915 aged just fifty-one.
Several genes have been found to be associated with Alzheimer’s, but none has been directly implicated as a root cause. Just getting old vastly increases your susceptibility to Alzheimer’s, but then the same could be said of almost all bad things. The more education you have had, the less likely you are to get Alzheimer’s, though having an active and questing mind, as opposed to just racking up a lot of classroom hours in one’s youth, is almost certainly what keeps Alzheimer’s at bay.
Alzheimer’s accounts for between 60 and 70 percent of all dementia cases and is thought to affect some fifty million people around the world, but Alzheimer’s is only one of about a hundred types of dementias, and it is often difficult to distinguish among them.
Part of the problem, as mentioned in chapter 22, is that Alzheimer’s trials must be done on laboratory mice, and mice don’t get Alzheimer’s. They must be bred to grow plaques inside their brains, and that means they respond to drugs in different ways than humans would. Many pharmaceutical companies have now given up altogether.
Interestingly, in the United States no one has died of old age since 1951, at least not officially, for in that year old age was banished as a cause from death certificates. In Britain, it is still allowed, though not much used.
The smell of a rotting corpse usually becomes horrible within two to three days, less if the weather is hot. Then, gradually, the smells begin to ease until there’s no remaining flesh and thus nothing left to cause odor.
It is a myth, and physiological impossibility, incidentally, that hair and nails continue to grow after death. Nothing grows after death.