The human lifespan may have reached its highest point, according to a new study.
Despite large increases in maximum life expectancy over the 20th century, the human body may not be able to live more than a year or so past the age of 115, according to a letter published Wednesday in the journal Nature.
Jan Vijg and colleagues at the Albert Einstein College of Medicine in the Bronx, New York, used databases such as the Human Mortality Database to track the maximum ages achieved in human populations over time.
The oldest person on record is Frenchwoman named Jeanne Calment, who died in 1997 at the ripe old age of 122.
Around that time in the 1990s, the growth in maximum life spans hit a plateau, the study said. In the nearly 20 years since then, none of the world's oldest people have matched or surpassed Calment's record. At the same time, there are more people living to 100 than there have been at any other point in the available records, suggesting the human species may have reached its limit.
While another "supercentenarian" like Calment might come along, Vijg's study suggests 122 might be very near an absolute maximum, where even the bodies of disease-free people begin to break down from a lifetime of cellular or molecular damage. A person would have about a 1 in 10,000 chance of living past the age of 125, the study said.
Vijg told CNBC he is also skeptical that pharmaceutical or genetic interventions will be able to push the ceiling higher anytime soon, since the mechanisms that repair damage in the body are "unbelievably complex."
But instead of trying to push the maximum age higher, he said it might make more sense to focus on improving quality of life in older people.
"My main concern is, say, 10 years from now, I don't want to be sick," Vijg said. "I will be lucky if I can make it to 105 or whatever, and then drop dead because my body has had it. When people are in wheelchairs, suffering disabilities, unable to do things like use the bathroom by themselves, that is when you have real problems."
Vijg also said that the medical field spends much more money on studying or curing individual diseases than it does on studying aging itself.
"We should certainly spend a lot more money focused on studying aging itself. Because if you study aging itself, you may be able to develop drugs that can do something against aging itself, and prevent or reverse all of these diseases simultaneously," he said.