The death of the world’s oldest person at 118 has reignited a debate among scientists for centuries: Do healthy people have a finite lifespan?
Spanish great-grandmother Maria Branyas Morera has claimed the title of oldest living person at 115, following the death last week of French nun Lucile Randon, according to Guinness World Records.
Back in the 18th century, French naturalist Georges-Louis Leclerc theorized that a person who had not suffered accidents or disease could theoretically live up to 100 years.
Since then, advances in medicine and improved living conditions have pushed the limits back decades.
In 1995, Frenchwoman Jeanne Calment celebrated her 120th birthday, marking a new milestone for her.
Calment died two years later at the age of 122. She’s still the oldest living person ever – at least that’s been proven.
An estimated 593,000 people will be aged 100 or older by 2021, up from 353,000 a decade ago, according to the United Nations.
According to the Statista data agency, the number of centenarians is expected to more than double in the next decade.
The Comte de Buffon may also be surprised by the rise of supercentenarians (people aged 110 or over), whose numbers have been increasing since the 1980s.
The natural limit is 115?
So how far can we go? Scientists disagree, with some insisting that our species’ lifespan is strictly biologically limited.
In 2016, geneticists wrote in the journal Nature that human longevity had not improved since the late 1990s.
By analyzing global population data, they found that since Calment’s death, the maximum human lifespan has declined — even though there are more elderly people in the world.
“They came to the conclusion that there is a natural limit to human lifespan, which is limited to around 115 years,” French demographer Jean-Marie Robin told AFP.
“But this assumption has been somewhat questioned by many demographers,” said Mr Robine, a centenarian expert at the INSERM Institute for Medical Research.
The 2018 study found that while the death rate rises with age, it slows after the age of 85.
Around the age of 107, the death rate peaks at 50-60% per year, the study said.
“According to this theory, if there are 12 people who are 110 years old, then six will live to be 111, three will live to be 112 and so on,” Mr Robine said.
But the more supercentenarians there are, the better the chances are that some will live to a record age.
If there are 100 supercentenarians, “50 will live to 111 and 25 to 112,” Mr Robin said.
“Thanks to the ‘volume effect,’ there is no longer a fixed limit to lifetime.”
However, research published this year by Mr Robin and his team showed that the death rate continued to rise after the age of 105, further narrowing the gap.
Does this mean there is a hard upper limit to our lifespan? Mr. Robin won’t go that far.
“We will continue to explore as always, and the health status of the elderly will gradually improve,” he said.
Other experts are also cautious about which side to choose.
“There are no clear answers,” said France Messler, a demographer at the French Institute for Demographic Research (INED).
“Even though they are increasing, the number of people reaching advanced age is still so small that we still cannot make any statistically significant estimates,” she told AFP.
Therefore, it may be necessary to wait for a growing number of supercentenarians to examine the “volume effect”.
Of course, some future medical breakthroughs may soon upend what we know about death.
French gerontologist Eric Boulanger said that “genetic manipulation” can make some people live to 140 or even 150 years old.
(Aside from the title, this story is unedited by NDTV staff and published via a syndicated feed.)
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