Has life expectancy finally reached its limit?

If it can hold up to 2029, says Ray Kurzweil, Google’s chief futurist, medical advances will start “adding a year every year to life expectancy. And with that I’m not talking about life expectancy at birth, I’m talking about Life expectancy in the remaining years.” Curious readers may wonder what this trend will do to global population growth, but I will limit myself to a brief review of the survival facts.

In 1850, life expectancy for men and women ranged around 40 years in the United States, Japan, and most of Europe. Since then, these values ​​have seen an impressive almost perfect linear increase which has caused them to nearly double. Women live the longest in all societies, with the current maximum being 87 or more in Japan.

It is entirely possible that this trend will continue for a few more decades, considering that between 1950 and 2000, the life expectancy of elderly people in rich countries grew by about 34 days a year. But without the fundamental discoveries that are changing the way we age, the trend toward longer lives is sure to slow and eventually disappear. The long-term trajectory of Japanese women’s life expectancy — which rose from 81.91 years in 1990 to 87.26 years in 2017 — fits in a symmetric logistic curve already approaching the roughly 90-year convergence line. Tracks for other wealthy countries also give a rough estimate of the ceiling values. Available records of the twentieth century reveal two distinct periods of increased longevity: the spread of fast linear gains (about 20 years in a half century) until 1950, followed by slower gains.

If we are still far from the human life time limit, the largest survival gains should be recorded among the elderly, that is, those aged 80–85 should gain more time than those aged 70–75. This was in fact the case in studies conducted in France, Japan, the United States, and the United Kingdom since the 1970s and early 1990s, but since then, the gains have leveled off.

There may not be a specific limit genetically programmed over a lifetime – just as there is no genetic program that limits us to a specific running speed (see How Race Helped Chasing, p. 44). But age is a physical characteristic that results from the interaction of genes with the environment. The genes themselves can introduce biophysical limits, as can environmental influences such as smoking.