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. The Florey Institute in Melbourne, for instance, studies menopause using sheep for the simple reason that sheep are almost the only land-based creatures known to experience menopause, too. At least two species of whales also go through it. Why any animals get it is a question yet to be answered.
The bad news is that menopause can be a terrible ordeal. Hot flashes are experienced by about three-quarters of women during menopause. (It is a feeling of sudden warmth, generally in the chest or above, induced by hormonal changes for unknown reasons.) Menopause is related to a fall in production of estrogen, but even now there isn’t any test that can definitively confirm the condition. The best indicators for a woman that she is entering menopause (a stage known as perimenopause) are that her periods become irregular and she is likely to find herself experiencing a “sense that things aren’t quite right,” as Rose George wrote for the Wellcome Trust publication Mosaic.
Menopause is as much a mystery as aging itself. Two principal theories have been advanced, known rather neatly as the mother hypothesis and the grandmother hypothesis. The mother hypothesis is that childbearing is dangerous and exhausting, and it becomes more of both as women age. So menopause may simply be a kind of protection strategy. By no longer having the wear and distraction of further childbirth, a woman can better focus on maintaining her own health while completing the rearing of her children just as they are entering their most productive years. This leads naturally to the grandmother hypothesis, which is that women stop breeding in middle age so that they can help their offspring raise their children.
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.
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A STUDY BY the Albert Einstein College of Medicine in New York in 2016 concluded that however much medical care may advance, it is unlikely that many people will ever live past about 115 years. On the other hand, Matt Kaeberlein, a University of Washington biogerontologist, thinks that young people alive today may routinely live up to 50 percent longer than people do now, and Dr. Aubrey de Grey, chief science officer of the SENS Research Foundation of Mountain View, California, believes that some people alive right now will live to be one thousand. Richard Cawthon, a geneticist at the University of Utah, has suggested that such a span is at least theoretically possible.
We’ll have to wait and see. 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. The Gerontology Research Group in Los Angeles keeps track, as well as it can, of all the world’s supercentenarians—that is, people who have reached their 110th birthday. But because records in much of the world are poor and because a lot of people for various reasons would like the world to think they are older than they really are, the GRG researchers tend to be cautious in admitting candidates to this most exclusive of clubs. Usually about seventy confirmed supercentenarians are on the group’s books, but that is probably only about half the actual number in the world.
The chances of reaching your 110th birthday are about one in seven million. It helps a lot to be a woman; they are ten times more likely to reach 110 than a man. It is an interesting fact that women have always outlived men. This is a little counterintuitive when you consider that no man has ever died in childbirth. Nor, through much of history, have men been as closely exposed to contagions through nursing the sick. Yet in every period in history, in every society examined, women have always lived several years longer on average than men. And they still do now, even though men and women are subjected to more or less identical health care.
The longest-lived person that we know of was Jeanne Louise Calment of Arles, in Provence, who died at the decidedly ripe age of 122 years and 164 days in 1997. She was the first person to reach not only 122 but also 116, 117, 118, 119, 120, and 121. Calment had a leisurely life: her father was a rich shipbuilder and her husband a prosperous businessman. She never worked. She outlived her husband by more than half a century and her only child, a daughter, by sixty-three years. Calment smoked all her life—at the age of 117, when she finally gave up, she was still smoking two cigarettes a day—and ate two pounds of chocolate every week but was active up to the very end and enjoyed robust health. Her proud and charming boast in old age was, “I’ve never had but one wrinkle, and I’m sitting on it.”
Calment was also a beneficiary of one of the most delightfully misjudged deals ever made. In 1965, when she ran into financial difficulties, she agreed to leave her apartment to a lawyer in return for a payment of 2,500 francs a months until she died. Because Calment was then ninety, it seemed a pretty good deal for the lawyer. In fact, it was the lawyer who died first, thirty years after signing the deal, having paid Calment more than 900,000 francs for an apartment he was never able to occupy.
The oldest man, meanwhile, was Jiroemon Kimura of Japan, who died aged 116 years and 54 days in 2013, after a quiet life as a government communications worker followed by a very long retirement in a village near Kyoto. Kimura lived a healthy lifestyle, but then millions of Japanese do. What enabled him to live so much longer than the rest of us is a question to which there is no answer, but family genes seem to play a significant role. As Daniel Lieberman told me, reaching 80 is largely a consequence of following a healthy lifestyle, but after that it is almost entirely a matter of genes. Or as Bernard Starr, a professor emeritus at City University of New York, put it, “The best way to assure longevity is to pick your parents.”
At the time of writing, there were three people on Earth with a confirmed age of 115 (two in Japan, one in Italy) and three aged 114 (two in France, one in Japan).
Some people live longer than they ought to by any known measures. As Jo Marchant notes in her book Cure, Costa Ricans have only about one-fifth the personal wealth of Americans, and have poorer health care, but live longer. Moreover, people in one of the poorest regions of Costa Rica, the Nicoya Peninsula, live longest of all, even though they have much higher rates of obesity and hypertension. 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. It is an extraordinary fact that having good and loving relationships physically alters your DNA. Conversely, a 2010 U.S. study found, not having such relationships doubles your risk of dying from any cause.