A study published by researchers from the Albert Einstein College of Medicine in October 2016 suggested that for most people, the natural limit for life span is about 115 years.
Maximum And Average Life Spans
Researchers, however, now argue in a new study published in the journal Nature that there is no evidence that the maximum life span of humans has stopped increasing.
Bryan Hughes and Siegfried Hekimi, from McGill University in Montreal, analyzed the life span of the longest-living people from the UK, the United States, France, and Japan for each year since 1968 and found no evidence that support the idea for a longevity limit. The researchers said that if a maximum life span does exist, it still has to be reached or identified.
"We just don't know what the age limit might be. In fact, by extending trend lines, we can show that maximum and average life spans, could continue to increase far into the foreseeable future," Hekimi said.
Average life spans change, but the overall trend is that longevity is going up. In 1920, newborns in Canada could live up to 60 years. Life expectancy, however, increased for those born in the 1980, who could expect to live to 76 years of age. Today, a newborn Canadian could live up to 82 years. In the United States, life expectancy in the 1990s was just around 50 years, but babies born in the country today could expect to live to about 79 years.
As for the maximum life span, the researchers said that there are variations. There are years in which the maximum life span drops a little, and there are other years when it jumps.
Human Life Span Not Limitless
The researchers do not argue that the human life span is limitless. What they contend is that it is premature to accept that there exists a maximum life span for humans.
They also said that it is impossible to give a prediction on how future life spans in humans may look like. Hekimi said that three centuries ago, many people had short lives, and they would not have believed if they were told that one day most people may live up to 100 years old.
The researchers said that it is possible that humans will continue to live longer and thus may survive beyond the 115 years average life span cap that was put forward by the October 2016 study. Researchers of the earlier study, which was published in the journal Nature, said that in any given year, the likelihood that at least one individual in the world will live beyond 125 years are less than 1 in 10,000.
The fountain of youth may be elusive, but medical intervention, technology, and improvement in living condition may get people to live longer.
"It was reasonable that when everybody lived to 50 that the very long lived, for whatever reason — genetics or luck — would make it to 80," Hekimi said. "If people live on average to 80 or 90, like they do now, then the very long lived make it to 110 or 120. So if the average life span keeps expanding, that would mean the long-lived would live even longer, beyond 115 years."