Want a slimmer, healthier community? Try building more sidewalks, crosswalks and bike paths.
A study authored by Professor David Bassett Jr. from the Department of Kinesiology, Recreation and Sport Studies at the University of Tennessee, Knoxville, and three other researchers was published today in the American Journal of Public Health, concluding that communities with more walkers and cyclists are healthier than those where people must rely on cars to get around.
John Pucher of Rutgers University was the lead researcher on the project. Ralph Buehler of Virginia Tech and Dr. Andrew Dannenberg of the National Center for Environmental Health at the Centers for Disease Control and Prevention collaborated on the project.
The researchers analyzed city- and state-level data from the United States and international data from 15 countries to study the relationship between "active travel" -- bicycling or walking rather than driving -- and physical activity, obesity and diabetes.
The results showed that more than half of the differences in obesity rates among countries is linked to walking and cycling rates. In addition, about 30 percent of the difference in obesity rates among states and cities is linked to walking and cycling rates.
Bassett said this study is part of the mounting evidence that active travel has significant health benefits.
"Perhaps the greatest strength of our analysis was that it showed that the relationship between active travel and health was discernible at three different geographic levels: international, state and city," the study says.
The study also reinforces the need for U.S. cities to encourage more walking and cycling for daily travel by providing safe, convenient and attractive infrastructure, such as sidewalks, crosswalks, bike paths and lanes, and intersection modifications that protect pedestrians and cyclists.
"A growing body of evidence suggests that differences in the built environment for physical activity (e.g., infrastructure for walking and cycling, availability of public transit, street connectivity, housing density and mixed land use) influence the likelihood that people will use active transport for their daily travel," the study says. "People who live in areas that are more conducive to walking and cycling are more likely to engage in these forms of active transport."
The researchers also suggest that infrastructure improvements should be combined with restrictions on car use, such as car-free zones, traffic calming in residential neighborhoods, reductions in motor vehicle speeds, and limited and more expensive car parking.
"Moreover, land-use policies should foster compact, mixed-use developments that generate shorter trip distances that are more suitable for walking and biking," they wrote.
Overall, the U.S. doesn't measure up well.
"European countries with high rates of walking and cycling have less obesity than do Australia and countries in North America that are highly car-dependent," the authors wrote.
The relationship between active travel and health seems clear even when you look at various places in the U.S.
Comparing all 50 states and 47 of the 50 largest American cities, the researchers found that states with higher rates of walking and cycling had a higher percentage of adults who achieved recommended levels of physical activity, a lower percentage of adults who are obese, and a lower percentage of adults with diabetes.
The study notes that there have been large increases in obesity rates over the past 30 years. The World Health Organization estimates that more than 300 million adults are obese, putting them at increased risk for diabetes, hypertension, cardiovascular disease, gout, gallstones, fatty liver and some cancers.