By Chris Adams

Has the first person who will live to 150 already been born?

If they have been, will they be happy about that fact?

S. Jay Olshansky, a professor in the School of Public Health at the University of Illinois at Chicago, isn’t so sure about either question. Despite some bold predictions by researchers – often trumpeted on magazine covers – that lifespans will expand dramatically in coming decades, Olshansky says there’s plenty of reason to be skeptical of such claims.

“The human body wasn’t designed for the long-term,” Olshansky told a group of National Press Foundation fellows. “We are using it beyond its biological warranty period.”

Olshansky talked about the reasons why humans might not last as long as some think or hope – even if researchers are able to cure cancers, heart disease, diabetes and other major killers. The reasons deal with the body’s physical limits, and how bones, muscles and other body parts break down after repeated use.

“The human body cannot be pushed much further than it already has been pushed,” he said. “We have to be careful what we wish for.”

True, smoking and other lifestyle factors kill people early. “There are lots of things you can do to shorten your lifespan,” he said. “There’s very little you can do to extend it.”

That’s not to say that segments of the population won’t see dramatic increases in aging – just like some subpopulations have seen their lifespans actually contract in recent years.

“There will be a divergence,” he said, “with some doing well and some doing poorly.”