But that doesn't mean science can't help us live longer.  We just
need to focus our energy on the right target, according
to Eileen
Crimmins, who studies longevity at the University of Southern
California. 

Of the hopes many people have of living to be 150 years old, she
says, "I think that's all pretty much nonsense."  But that's
because she has a much more interesting goal in mind — and it's
one you and I could actually benefit from. 

In the US, that's tricky because Americans
under the age of 75 are generally less healthy than people in
similar countries.  We're better than our peers at treating things
like cancer.  But health problems we're
surprisingly bad at tackling, like heart disease, lung
disease, drug problems, sexually transmitted infections, and
obesity sicken and kill people early in life. 

Ilya
Naymushin/Reuters

"We're trying to get people healthy up to the age of 75 or 80,"
Crimmins said.  She calls this idea extension of quality of life
within a given lifespan — basically, you may not live any longer,
but you'll be healthier for more of the years you're alive. 

"I'm not worried much about what happens after age 100," Crimmins
said. " I don't believe many people will make it beyond 100, and
most people who do are relatively healthy for that age."