Longevity and aging

Almost eight years ago I wrote a post on this topic in this blog, which contained a figure that I built starting from data provided by the Spanish Institute of Statistics, which showed mortality data for Spain in three different years: 1900, 1991 and 2013. The three curves in the figure represent the percentage of people who have reached a certain age and will die during the next year. I’m showing here an equivalent figure, with updated data that correspond to the years 1900, 1991 and 2022, as we now have more recent data.

As I said then, the figure shows that medical advances have reduced mortality, especially at the beginning and the end of life, but their effects are little noticeable for people between 20 and 40 years old. The mortality curve, which in 1900 was U-shaped, is approaching an inverted L, with a very low rate for almost all of life and a fairly abrupt rise after age 80.

Will robots help us to be immortal?

The second method that, according to optimists, will help us achieve immortality, is based on the following idea:

We will soon be able to design tiny robots that, introduced into our blood, will attack and destroy every pathogenic microorganism, as well every cancer cell, leaving the normal cells of the body intact. When all diseases disappear, we will automatically be immortal.

Will we be immortal by increasing our life expectancy?

Pieter van Lint - Allegory of immortality

This method is based on the following idea: if we could manage to increase our life expectancy by more than one year per year, we would automatically be immortal. Mathematically, this idea is correct. But is there any chance that it will happen in practice?

One problem is that the increase in life expectancy is slowing down, and has even reversed.

First, we must clear up a misunderstanding. Two completely independent concepts should not be confused:

Four ways to achieve immortality

Herodotus

As I have explained in previous posts in this blog, some people believe that we are about to achieve immortality. Of course, depending on the way to do it, it might not be applicable to everyone, because it would be very expensive. Perhaps it would just be feasible for a few enormously wealthy people. Or maybe it could be done in a more democratic way, so that everybody would be immortal. Many journalists, politicians, tycoons, philosophers, futurologists, and even ordinary people are convinced that sooner or later all of us, or at least some of us, will be immortal.

This is not a new hope; it comes from deep in the past. One of the oldest known masterpieces of literature, the Epic of Gilgamesh, written 4,000 to 4,500 years ago, deals with the quest for immortality. We also have the legend of the fountain of youth, which would give immortality to those who drink from its waters. According to Herodotus, it would be located in Ethiopia, although some say that Ponce de León searched for it in vain in Florida.

Will we live 500 years?

James H. Schmitz

A few years ago, especially in 2015 and 2016, news began to appear in the mass media announcing the imminence that our life expectancy is going to rise in an accelerated way, so we’ll soon achieve immortality. At that time I wrote in this blog three posts (this, this and this) where I declared myself skeptical about these forecasts. In another post, also published in 2016, I distinguished between two very different concepts:

• Life expectancy: the average duration of human life. Although it depends on the age of the person, the value usually given corresponds to the moment of birth. Life expectancy has been growing progressively in recent centuries, mainly due to advances in medicine, although recent data from the UN seem to indicate that this increase is decreasing.
• Longevity: the maximum duration of human life. Its value seems to be around 120 years, and no significant increase is noted in recent decades. In fact, there are only two people who were thought to have exceeded that longevity, the Japanese Shigeziyo Izumi and the French Jeanne Calment, but both cases are currently in doubt. The first lost his title of the longest-lived man in the world when it was discovered that his date of birth could actually correspond to a brother of the same name, older than him, who died quite young. In the case of the French woman, there is a controversial Russian study that asserts that her daughter could have exchanged her identity for her mother’s when the latter died, supposedly in 1934.

Jules Verne’s scientific predictions for 2889

Jules Verne

In a science fiction story published in English in the United States in 1889, entitled In the Twenty-Ninth Century and subtitled One Day of an American Journalist in 2889, Jules Verne made several scientific predictions that, according to him, would take almost a millennium to be put into practice. Let us look at a few of the most interesting:

•         The average lifetime of the human population will have increased from 37 in 1889, to 68 in 2889. According to the UN, the average longevity in the world exceeded 68 years in the five-year period from 2005 to 2010, almost nine centuries before Verne’s forecast. Here, as elsewhere, he underestimated.

•         The land and sea voyages of the nineteenth century will have been replaced in the XXIX by air travel, or intercontinental underwater pneumatic tubes. At present, little more than a century after Verne’s story, although air travel has achieved great primacy, land and sea travel continue to exist, and for distances less than a thousand kilometers make a successful competition to air travel. Intercontinental pneumatic tubes, on the other hand, are still science fiction, although there some recent steps in this direction.

Aging and longevity

Life span of several species.
Data from Science News, 7-13-2016

It is often said that aging has been favored by natural selection to facilitate the replacement of one generation by the next. According to Alex Kowald (University of Newcastle), this statement is nonsense. It is evident that natural selection would favor individuals aging less and able to reproduce longer. Peter Medawar, Nobel Prize in Physiology and Medicine (1960), said in 1951: Wild living beings do not live long enough for natural selection to act on genes that affect aging. Death overtakes them long before they are near their limit of longevity.

Each species of living beings seems to have a maximum longevity. In humans, according to appearances, this limit does not seem to go far above 110 years. The longest proven human longevity corresponds to Jeanne Louise Calment (a French woman), who died at age 122.5.