To get around stapleton, colorado, all you really need are your feet. Residents of the 4,700-acre Denver suburb stroll or cycle to downtown offices and schools within minutes, weaving through forested greenways and bike trails. Along the way, they can stop for a coffee or gaze at public art. On weekends, they can chat with neighbors while buying arugula at the local farmers’ market, take a bus to downtown Denver, or just settle into the grass of the 80-acre “Central Park,” an emerald gem of open space at the town’s core. The community’s mix of single-family homes, townhouses, and apartments—with units reserved for lower-income citizens—all meet state environmental building standards.

It’s no surprise the town touts itself as a model of smart growth and environmentally sensitive development. But recent research suggests that communities like Stapleton are not just more eco-friendly, they’re also healthier places to live.  “We hadn’t really looked into the way neighborhoods can impact health until recently, but it’s starting to look like one of the missing pieces to the public-health puzzle,” says Laura Brennan Ramirez, an assistant professor at Saint Louis University who recently authored a study on the issue.

To understand what makes a healthy neighborhood, it helps to know what makes an unhealthy one. In the past few years, public-health experts have been researching the effects of urban sprawl and car-dependent suburbs. What they’re finding is that people living in these areas—where homes and businesses are spaced far apart along roadways that require cars to get from place to place—face more health problems than those living in more compact neighborhoods that allow easy walking and biking.

The bulk of that research has focused on the relationship between neighborhoods and the levels of physical activity and obesity of their residents. People living in low-density neighborhoods, it turns out, are more sedentary and heavier than those who live in more compact suburbs or cities. In 2003, researchers at the University of Maryland published a study of nearly 200,000 people in 448 counties and metropolitan areas, and found that as the level of sprawl increased, so did the study participants’ high blood pressure, weight gain, and the likelihood of being obese. In a 2004 study led by Lawrence Frank, an urban planning professor at the University of British Columbia, researchers surveyed nearly 11,000 people in Atlanta, the most sprawled region in the U.S. They found that each additional hour spent in a car daily was associated with a six-percent increase in the risk of obesity.  

But weight gain and cardiovascular disease aren’t the only problems.  All that driving, of course, means high levels of vehicle emissions and pollution. People who live near busy streets can be exposed to two or three times more particulate matter, a harmful byproduct of car emissions, than those who don’t. Pollution can create respiratory ailments and other health problems, especially in sensitive populations such as children.