Is the time you spend in your car making you fat? A recent study by researchers at the University of Illinois suggests it may.
After analyzing data from 1985 to 2007, professor Sheldon H. Jacobson and two students found a 99 percent correlation between vehicle use and national obesity rates. Their findings were published in the journal Transport Policy last month.
The researchers looked at annual vehicle miles traveled per licensed driver as a surrogate measure for a person's total sedentary time.
"There is no way to exercise in a car, so [the study] makes sense to me," said Vonda Wright, director of the Performance Research Initiative for the Master's Athlete at UPMC Sports Medicine. "If you have a 45-minute drive to and from work, and then you sit at your desk, that's 10 hours of just sitting around. That's hard to overcome."
Michael Yao, director of geriatric education at Forbes Family Practice in Monroeville, agreed that vehicle miles traveled per adult correlates best with obesity rates. But, he cautioned, "there are many other things that contribute to obesity. We're getting older, we keep eating [more], and our jobs keep getting more technical and less physical. Our kids, who are not driving yet, are increasingly obese."
Fewer people were overweight before the automobile became the prevalent mode of transportation, Mr. Jacobson said.
Dr. Wright, who lived in New York City and Portland, Ore., before coming to Pittsburgh, agreed.
"If you look at cities which are walking cities, you don't see the kind of weight problems we see in more sedentary communities," she said.
According to his data, if every driver drove about 12 miles less per day (and walked or cycled instead), obesity would be virtually eliminated, Mr. Jacobson said.
That amounts to about a third of the miles the average driver drives each day and is effectively impossible as a goal, Mr. Jacobson acknowledged. But, he said, if every licensed driver reduced his or her automobile travel by just one mile per day (and walked instead), in six years almost 5 million fewer adults would be classified as obese.
Dr. Yao said he agreed with Mr. Jacobson's premise that making communities more walking- and cycling-friendly should reduce obesity rates. But he cautioned that because obesity has so many causes, it isn't clear that just reducing driving would change current trends.
"His general statement is that it would be nice if we could improve the infrastructure so that people could walk or ride a bike to local places where they live without having to resort to a car," said Mr. Yao. "But if you live in the suburbs and you are far away from where you need to go, it's hard to change how you get from point A to point B. It would have been nice to see from Dr. Jacobson how much of the driving is related to things we cannot change, such as driving to and from work."
Making community infrastructure more friendly to walkers and cyclists would have a more enduring impact on the obesity rate than "tactical interventions like taking soda machines out of schools and adding 15 minutes of recess time," Mr. Jacobson said.
It will take years to re-engineer communities to make them more walker-friendly. In the meantime, people can help themselves by not eating in the car, by getting out of the car and going into the bank or the pharmacy instead of using drive-thru windows, and by making sure to get at least 30 minutes of exercise five days a week, said Reggie Dulaney, a personal trainer at Panthro Fitness in Pittsburgh.
Jack Kelly: firstname.lastname@example.org or 412-263-1476.