Atlanta ? Nearly one in four people in the Atlanta area are exercise enthusiasts stuck in neighborhoods without sidewalks or other walking amenities, according to a study that illustrates a problem for many Americans.

Researchers said the findings point to the need for more exercise-friendly places to live.

“The bottom line is the built environment really does matter to health,” said Lawrence Frank, a University of British Columbia researcher who led the study.

Walkable, mixed-use neighborhoods have sidewalks leading to nearby shops, restaurants or other destinations. They are built in a way that makes it easier to walk and get to buses and trains. Many are older neighborhoods, located in more urban areas.

Frank is among a group of scientists who have shown that people who live in walkable neighborhoods tend to weigh less than people who live in more isolated and car-dependent areas.

“He’s the first one to make a connection between land use and obesity,” said Christopher Leinberger, director of the University of Michigan’s real estate program.

Frank’s current study examined whether a community’s walkability affected obesity rates. The research showed that exercisers had a similarly low obesity rate whether they lived in walkable neighborhoods or not. It was 12 percent for those in walkable areas versus 15 percent in nonwalkable neighborhoods, a difference that was not statistically significant.

Among those who prefer to drive, however, about 21.5 percent were obese, and it also didn’t matter whether they lived in walkable or nonwalkable neighborhoods.

The distances driven were also noted. Exercisers in walkable neighborhoods drove 26 miles a day, while those in nonwalkable neighborhoods drove about 37 miles.

Among nonexercisers, those in walkable neighborhoods drove 26 miles, and compared to 43 miles in areas that were mostly car-friendly.

“Walking and driving really change a lot in different neighborhood types, regardless of people’s preferences,” Frank said.

The study is based on detailed surveys done in the 13-county Atlanta region in 2001-02. The results, which are being published this fall in a peer-reviewed journal, Social Science & Medicine, are based on responses from 1,432 people. Twenty-three percent of them were exercisers living in places more conducive to driving than walking.