Experts: Impossible to predict longevity

CHICAGO, Oct. 1 (UPI) -- Experts say it's impossible to determine an individual's likely longevity, including that of 72-year-old Republican U.S. presidential nominee John McCain.

Political pundits who fear a possible ascension to the presidency by Alaska Gov. Sarah Palin, the Arizona U.S. senator's pick as vice presidential running mate, point out that actuarial tables predict someone of McCain's age may not live long enough to serve out one or two full terms.

But in reality, such broad numbers cannot predict any one individual's odds of survival, experts told the Chicago Tribune, saying the keys to a long life depend such elusive factors such as genetics, stress levels and how much mental activity a person gets.

Generally, however, some scientists say that if a person reaches 70 without suffering a host of health problems, odds are better they will survive even deeper into old age.

"The older you get, the higher the probability is that you're going to live even longer," said longevity researcher Jay Olshansky, a professor of public health at the University of Illinois at Chicago.