After French nun Lucile Randon died last week, Spanish great-grandmother Maria Branyas Morera, 115, has taken the title of oldest person, according to Guinness World Records.
Back in the 18th century, the French naturalist Georges-Louis Leclerc, known as the Comte de Buffon, assumed that people who did not suffer from accidents or diseases could live for a maximum of 100 years.
Since then, medical progress and improved living conditions have reduced these limitations over the decades.
A new milestone was reached when Frenchwoman Jeanne Calment celebrated her 120th birthday in 1995.
Calment died two years later at the age of 122. He remains the oldest person to have ever lived – as verified, at least.
According to the United Nations, there will be an estimated 593,000 people who will be 100 years or older by 2021, up from 353,000 in the previous decade.
The number of centenarians is expected to more than double over the next decade, according to data agency Statista.
Comte de Buffon may be surprised by the rise of supercentenarians – people aged 110 or more – whose numbers have been increasing since the 1980s.
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The natural limit at 115?
So how far can we go? Scientists disagree, with some arguing that the lifespan of our species is limited by strict biological constraints.
In 2016, geneticists writing in the journal Nature said there had been no improvement in human longevity since the late 1990s.
Analyzing global demographic data, they found that the maximum lifespan of humans has decreased since Calment’s death – even though there are more elderly people in the world.
“They concluded that human lifespan has a natural limit and that longevity is limited to about 115 years,” French demographer Jean-Marie Robine told AFP.
“But this hypothesis is partially refuted by many demographers,” said Robine, centenarians specialist at the medical research institute INSERM.
Research in 2018 found that the death rate increases with age, then decreases after 85.
Around the age of 107, the death rate peaks at 50-60% per year, said the research.
“According to this theory, if there are 12 people who live to be 110, six will live to be 111, three will live to be 112, and so on,” Robine said.
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Numbers game
But the more supercentenarians, the higher the chance that some will have to live to make a lifetime record.
If there are 100 supercentenarians, “50 will live to 111, 25 to 112,” says Robine.
Thanks to the ‘volume effect’, there is no longer a limit to longevity.
However, Robine and his team published research this year that will show that the death rate continues to rise beyond the age of 105, narrowing the window.
Does this mean there is a hard ceiling on how long we can live? Robine will not be far away.
“We will continue to make discoveries, as we do, and the health of the oldest people will improve,” he said.
Other experts are also cautious about choosing sides.
“There is no definitive answer for the moment,” said France Mesle, a demographer at the French institute for demographic studies (INED).
“Despite the increase, the number of elderly people is still small and we still cannot make statistically significant estimates,” he told AFP.
So, it may be worth waiting for the growing number of supercentenarians to test the “volume effect”.
And surely some medical breakthrough in the future could upend everything we know about death.
Eric Boulanger, a French doctor specializing in old age, said that “genetic manipulation” could allow some people to live to 140 or even 150 years.