New York City's life expectancy is increasing at a faster rate than in other parts of the country; in 2004 alone, New Yorkers gained five months of life on average, far outpacing the national average increase of a month or two a year.
What accounts for this longevity?
...researchers believe that New York City residents may simply be healthier than other Americans, in large part because -- unlike many other Americans -- they walk almost everywhere. As New York Magazine notes,
New York is literally designed to force people to walk, to climb stairs -- and to do it quickly. Driving in the city is maddening, pushing us onto the sidewalks and up and down the stairs to the subways. What's more, our social contract dictates that you should move your ass when you're on the sidewalk, so as not to annoy your fellow walkers.
Read in full - 'City Dwellers Live Longer, Save More by Driving Less'