People who use public transit are three times more likely to meet fitness guidelines than those who don't, say researchers at the University of British Columbia.

That conclusion comes from an examination of telephone travel surveys from metropolitan Atlanta, Ga., showing transit riders met requirements by walking to and from stops.

Researchers used the Heart and Stroke Foundation of Canada's suggested daily minimum of physical activity of 30 minutes of moderate physical activity a day, five days a week.

The survey also suggests the more people drove their cars, the less likely they were to get their 30 minutes of daily physical activity.

"The idea of needing to go to the gym to get your daily dose of exercise is a misperception," associate professor Lawrence Frank, who teaches community and regional planning, said in a release. "These short walks throughout our day are historically how we have gotten our activity.

"Unfortunately, we've engineered this activity out of our daily lives."

The report, published in the current Journal of Public Health Policy, does not examine motivation, but its authors suggest some possibilities.

"Whether these results may be caused by transit users' preference for an active lifestyle, travel constraints, or choice of residential location warrants further analysis," they write.

The researchers conclude that making transit incentives more broadly available may produce indirect health benefits by getting people walking, even if it's just in short bouts.

The survey was based on interviews with 18,326 people who were asked to keep diaries of their modes of travel over the course of two consecutive days in 2001 and 2002.