Press watch: Public transport is good for your health and your wallet, according to scientists

Taking the train, tram or bus instead of your car increases physical activity so much that the average person drops more than six pounds in as little as a year.

The findings suggests that increasing the use of public transport could improve health and lower obesity levels.

"The built environment can constrain or facilitate physical activity. Understanding ways to encourage greater use of local environments for physical activity offers some hope for reducing the growth in the prevalence of obesity," said lead author Dr John MacDonald, at the University of Pennsylvania.

In a study published in the August issue of the American Journal of Preventive Medicine, researchers from the University of Pennsylvania, Drexel University and the RAND Corporation found that construction of a light-rail system (LRT) resulted in increased physical activity (walking) and subsequent weight loss by people served by the LRT.

In a study published in the American Journal of Preventive Medicine, researchers found that construction of a light-rail system (LRT) resulted in increased walking and subsequent weight loss by people served by the LRT.

An added benefit of public policy investments in LRT, on top of the general transportation benefits accrued, is the potential reductions in obesity in the population, " said Dr MacDonald.

Using two surveys, one collecting data prior to the completion of an LRT in Charlotte, North Carolina, the second after completion, investigators found that using light rail for commuting was associated with reductions in body mass index (BMI) over time.

LRT reduced BMI by an average of 1.18 kg/m2 compared to non-LRT users in the same area over a 12-18 month follow-up period.

This is equivalent to a relative weight loss of 6.45 lbs for a person who is 5'5. LRT users were also 81 per cent less likely to become obese over time.

Survey questions assessed level of physical activity, BMI, perception of the neighborhood environment, public transit use before and after LRT construction, any plans to use LRT when available, and actual LRT usage.