Walkable cities mean less obesity, prompting psychologist-urban planner collaborations

The more spread out a city is, the less people walk or bike and the more they drive, according to research on how a community's design can influence a person's daily physical activity.

Several health psychologists--through research collaborations with urban planners--hope to get people back to foot travel by paving the way for more activity-friendly communities. Such efforts may help fight the obesity epidemic, they say.

People who live in high sprawl areas--relying on cars since their homes, work and stores are far apart--weigh more than people who live in compact cities, according to a study in the American Journal of Health Promotion (Vol. 18, No. 1) by urban planning expert Reid Ewing, PhD, and colleagues Tom Schmid, PhD, Richard Killingsworth, Amy Zlot and Stephen Raudenbush, EdD.

For example, a person living in the study's most sprawling county--Geauga County, Ohio--weighed, on average, six pounds more and walked 79 minutes less each month than people living in the study's most compact area of New York County, which includes Manhattan. Furthermore, sprawling county residents were more likely to suffer from hypertension, a risk factor for obesity, according to the study.

Researcher James Sallis, PhD, a psychology professor at San Diego State University, says he is alarmed at the impact sprawling cities can have on people's health.

"Since the 1940s, we have been building our cities for cars and not for walking," says Sallis, an expert in physical activity interventions. "So we've gotten to the point in our suburbs where we can't walk anywhere."

Sallis--teaming up with psychologist Brian E. Saelens, PhD, and transportation expert Lawrence Frank, PhD--found that residents living in neighborhoods with higher density and connectivity as well as with more shops and homes mixed together walk 15 to 30 minutes more per week than residents who live in sprawling communities, according to a recent study in Annals of Behavioral Medicine (Vol. 25, No. 2).

Sallis says sidewalks, bike trails, easily accessible recreational facilities and prominently placed stairwells all spur physical activity.

Studying such environmental factors as a community's design and creating cities and buildings that re-engineer physical activity back into daily routines may go a long way toward curbing the nation's obesity epidemic, adds Tracy Orleans, PhD, a clinical health psychologist and a senior scientist at the Robert Wood Johnson Foundation (RWJF).

RWJF launched a $12.5 million, four-year initiative to support transdisciplinary research that identifies environmental factors and policies that can increase population-wide activity. Multidisciplinary research teams--including psychologists, urban planners, transportation engineers, architects and others--can apply for a grant through RWJF to conduct such research.

"Health psychologists increasingly are working at the forefront of public health on this," Orleans says. "We've learned that we need to intervene at multiple levels in countering obesity--not just in individual or worksite exercise programs but also through efforts to create environments that make it easier for people to be physically active."

--M. DITTMANN