No upper limit to how long humans can live: study

Toronto: There is no upper limit to extending our lifespan, say scientists who contradict existing theories which suggest that the maximum human age is peaking at around 115 years.

Emma Morano passed away last April. At 117 years old, the Italian woman was the oldest known living human being.

Super-centenarians, such as Morano and Jeanne Calment of France, who famously lived to be 122 years old, continue to fascinate scientists and have led them to wonder just how long humans can live. Earlier studies have concluded that the upper limit of human age is peaking at around 115 years.

Researchers from the McGill University in Canada analysed the lifespan of the longest-living individuals from the US, the UK, France and Japan for each year since 1968, and found no evidence for such a limit. If such a maximum exists, it has yet to be reached or identified, researchers said.

"We just don't know what the age limit might be. In fact, by extending trend lines, we can show that maximum and average lifespans, could continue to increase far into the foreseeable future," said Siegfried Hekimi, from McGill University.

Many people are aware of what has happened with average lifespans. In 1920, for example, the average newborn Canadian could expect to live 60 years; a Canadian born in 1980 could expect 76 years, and today, life expectancy has jumped to 82 years. Maximum lifespan seems to follow the same trend.

It is impossible to predict what future lifespans in humans might look like, Hekimi said. Some scientists argue that technology, medical interventions, and improvements in living conditions could all push back the upper limit.

"Three hundred years ago, many people lived only short lives. If we would have told them that one day most humans might live up to 100, they would have said we were crazy," said Hekimi.

The research was published in the journal Nature.