04/08/2011 08:54 am ET | Updated Jun 08, 2011

The Youngest And Oldest Cities In America, Health-Wise

Where does your city fall in terms of marital longevity and happiness? And what, exactly, does that have to do with its overall health?

Answers have arrived in the form of new rankings identifying the 10 "youngest" and "oldest" cities in the U.S., health-wise.

RealAge -- a site that tests users on how old their bodies actually think they are, based on some 50-plus factors -- has created its first-ever list of America's youngest and oldest cities. It collated data from RealAge tests taken by more than 27 million people since 1999.

Dr. Keith Roach, chief medical officer at RealAge, said there were a few other surprises, like the fact that Washington D.C. -- "not a city people typically think of as particularly health conscious" -- cracked the top 10 "youngest" list.

But the goal of the new research, he added, isn't just the gee-whiz factor; it's to get people to examine -- and maybe change -- how they live.

"If there's something that we've identified that as a community you don't do very well, then you as an individual can look at it and see what you should be doing," Roach said. "If you live in Chicago, for example, are you following other people's leads and regularly eating hot dogs or deep dish pizza for lunch? Because maybe you shouldn't do that so often."

The other aim is for city planners and public health officials to take stock of their area and break the cycle in cities with high concentrations of unhealthiness. Roach suggested that might include things like changing public transportation, to encourage people to be more active.

The "youngest" city in the U.S.? Salt Lake City, Utah, which did well in factors like the amount of sleep people get, whether they're smoke-free and whether they're active. (RealAge estimates that a daily, 30-minute walk can make a person 3.5 years younger on its test.) More than half of the top 10 cities were in the West -- a fact they chocked up to people there being more physically active.

On the other end of the spectrum, Tulsa, Oklahoma, was found to be the nation's "oldest" city.

In addition to ranking overall age, researchers also looked at individual factors like marital status (Nashville, Tennessee, took top prize for happy marriages), as well as sleep. Turns out "city that never sleeps" is a misnomer: New York actually ranked second in terms of cities where people clock enough shut eye.

Roach cautioned that the rankings are based on the answers of people who have taken the RealAge test and are not a universal sample, so they tend to be biased towards people with access to a computer. But he said that the study could, nonetheless, serve as springboard for change.

10 Youngest And Oldest Cities