Longer drives and larger waistlines

Everyone knows that time spent in a car can make you tense and anxious, especially in heavy traffic. Now researchers say driving may have another undesirable effect: It can increase your risk of obesity.

A new study found that people who take the car to work or shopping tend to weigh more than those who walk. Researchers who studied drivers and passengers in metropolitan Atlanta found that every additional half-hour spent in a car translated to a 3% greater chance of being obese. Lead author Lawrence D. Frank and colleagues at Georgia Tech University studied 10,898 Atlanta-area residents during 2001 and 2002, collecting information about their height, weight, driving behavior and walking patterns.

Most of the Atlantans, he found, spent about an hour every day driving or riding in an automobile, although some people averaged as many as five hours commuting. The average white man spent more than 80 minutes as a driver or passenger; white women, 72 minutes; black men, 64 minutes, and black women, 60 minutes. That didn’t include hours spent riding buses and trains.

“These findings are very transferable to the L.A. region because Atlanta is a ... sprawling environment like much of Los Angeles,” said Frank, now a professor at the University of British Columbia in Vancouver. “And with increased congestion, we’re spending more and more time locked up in our cars.”

The research was presented last week at an obesity conference in Williamsburg, Va.