Humans are unlikely ever to live beyond the age of 125, according to researchers who say we are already close to our limit.
The scientists studied survival data dating back to 1900 from more than 40 countries.
They found evidence of increasing average life expectancy, meaning that over time more people lived to a ripe old age.
Babies born in the US today can expect to live to just below 79, compared to 47 in 1900.
But the same study highlighted how unusual it was to live beyond 100, regardless of the year in which people were born.
The team calculated that 125 was likely to be the absolute limit of human lifespan due to genetic factors.
Lead researcher Professor Jan Vig, from the Albert Einstein College of Medicine in New York City, said: “Demographers as well as biologists have contended there is no reason to think that the on-going increase in maximum lifespan will end soon.
“But our data strongly suggests that it has already been attained and that this happened in the 1990s.
“Further progress against infectious and chronic diseases may continue boosting average life expectancy, but not maximum lifespan.”
The study, published in the journal Nature, focused on people living to 110 or older between 1968 and 2006 in the US, UK, France and Japan.
Age at death for these super-centenarians rose rapidly between the 1970s and early 1990s but reached a plateau in the mid-1990s.
The oldest verified person on record was French woman Jeanne Calment (1875-1997), who lived to be 122 years and 164 days.
She is followed by Sarah Knauss of the United States, who was born in 1880 and lived for 119 years and 97 days.
The oldest living person in the world right now is Italian Emma Morano, who was born in November 1899 and is presently 116 years and 312 days old.
With a top age so far of 122, humans are not the longest-living land animals on Earth.
That honour falls to Galapagos giant tortoises, which have been known to live to 152.