"More sprawl is less walking and reduced physical activity," says David Berrigan, program director at the National Cancer Institute. "That can have powerful health consequences because physical activity is very beneficial for preventing obesity, diabetes and cancer."
The study examined residents in Charlotte, N.C., after a new high-tech light rail system was installed in 2007. Their findings were that riding the rails led to more walking by an average of 1.2 miles a day.
Still, it's not as easy as moving into a townhouse and walking your way to health. Berrigan, who wasn't involved with the study but has done his own research on health and environment, says that race, income, behavior and other factors also play a role.
"It's not as simple as city good, suburbs bad," he says. "People at different times have demonized suburbs or cities — the suburbs are known for sloth and automobiles, cities for crime and pollution."
The research paints a more nuanced picture, he says. For example, children get more physical activity in the suburbs with cul-de-sacs and yards, and adults get more activity in the city where they don't hop into a car all the time.
Lynda Stratford has been living in Manhattan for almost four years, but previously she lived in Hong Kong. There, she says, the public transportation is much cleaner and efficient — train stations are like gleaming shopping malls. New York's subway, by comparison, is dank and dirty, she says, and Hong Kong has clever solutions like outdoor escalators that take commuters up and down the city's steep hills. If the United States invested more in public transport, she says, it's more likely that Americans would use it.
President Obama recently asked Congress for a major transportation overhaul that would put $50 billion into infrastructure, including 4,000 miles of rail tracks. Still, there are other changes that communities can make, says Berrigan. One of his favorites is community bike-share programs. "People thought that would only work in big, flat cities like New York, but it's been instituted in Rockville, Md., a midsized suburban town. People are seeing what's possible — they're fostering creative, active transport."
Ewing says that trying to get everyone to adjust to apartment living is not the answer — but he would like people to have more options. "We are not arguing — and this is important — that everyone should live in the city. But people should have the choice to live in more mixed-use areas."
Berrigan imagines a public health movement like the sanitation and health services that swept American cities in the late 1800's, this time with an eye toward built environments and transportation. "It's time to ask the question again," he says, "how can we make cities better?"