Tuesday, July 18, 2017

A communication published in the June 28, 2017 issue of the journal Nature refutes a letter authored by Xiao Dong, Brandon Milholland and Jan Vijg that appeared last year in the journal which proposed a fixed maximum human life span limit of approximately 115 years. In the current communication, researchers Bryan G. Hughes and Siegfried Hekimi concluded that there is no evidence to date for a limit to how long humans could live.

In their communication, Dr. Hughes and Hekimi point out the flaws in the letter that appeared in the earlier issue of Nature. "The analyses described by Dong et al. do not permit us to predict the trajectory that maximum life spans will follow in the future, and hence provide no support for their central claim that the maximum life span of humans is 'fixed and subject to natural constraints,'" Drs. Hughes and Hekimi write. "This is largely a product of the limited data available for analysis, owing to the challenges inherent in collecting and verifying the life spans of extremely long-lived individuals."

"We just don't know what the age limit might be," stated Dr. Hekimi, of the Department of Biology at McGill University in Quebec. "In fact, by extending trend lines, we can show that maximum and average life spans could continue to increase far into the foreseeable future."

Average life span has increased dramatically over the past century, and maximum life span appears to follow a similar trend. Advancements in medicine and technology could significantly change what is perceived to be the current upper life limit to human life span. According to Dr. Hekimi, it's impossible to predict what future human life spans will look like.

"It's hard to guess," he remarked. "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."