Active Voice: The Built Environment and Physical Activity
By Brian E. Saelens, Ph.D.

Viewpoints presented in SMB commentaries reflect opinions of the authors and do not necessarily reflect positions or policies of ACSM.

Brian E. Saelens, Ph.D., is an investigator at Seattle Children’s Research Institute and a Professor of Pediatrics and Psychiatry and Behavioral Sciences at the University of Washington. A member of ACSM, Dr. Saelens focuses his research on environmental factors and policies that impact physical activity, dietary behavior, and obesity. He also examines the efficacy of behavioral interventions for overweight children. See the April 2012 issue of ACSM’s Medicine and Science in Sports and Exercise® (MSSE) for a research article he coauthored titled “Neighborhood Environment and Psychosocial Correlates of Adults’ Physical Activity”.

Physical inactivity ranks among the leading contributors to morbidity and premature mortality in the U.S. Most U.S. adults continue to struggle with not getting the amount of daily physical activity recommended for achieving and sustaining health. This public health concern requires approaches that have population impacts. This has led to a growing interest during the past 10 years to examine issues beyond individual factors and programmatic interventions, in efforts to understand how one’s surrounding environment influences physical activity.

Working in collaboration with urban planners and other disciplines, the field has begun to identify which environmental factors are most consistently related to physical activity and also which of these relate to specific types of physical activity (e.g., transportation versus recreational walking – see Saelens & Handy, 2008 MSSE). For example, our article in the April MSSE which is based on a project led by Dr. James F. Sallis, Dr. Lawrence D. Frank, and myself, highlights the relationship between adults’ physical activity and the built environment factor of retail floor area ratio (FAR). Dr. Frank, an urban planner with spatial methodology expertise, describes FAR as a measure that combines land use mix (e.g., the mixing of residential and retail within a neighborhood) and pedestrian infrastructure (e.g., having stores close to sidewalks or streets rather than surrounded by surface parking). In this study, adults with higher FAR within 1 km of their homes had more overall physical activity and particularly higher transportation-related walking. We found that individual-level factors such as perceived barriers to physical activity and self-efficacy were related to physical activity, but that FAR was related to physical activity, even after we controlled for these individual-level factors.

A few limitations of this study include:
  • Our studies and those published by others point to the need for continued investigation into methods that allow for the accurate, complete, and feasible assessment of physical activity in time and space/context. These methodological studies will result in better categorization of physical activity type and purpose.
  • Identifying cross-sectional built environment factors related to physical activity takes us only so far. We need investment in evaluation of the impact of changes in the built environment and the effects of policy on changes in physical activity and other health behaviors.
Indeed, many health organizations including the Centers for Disease Control and Prevention and the Institute of Medicine have already recommended numerous environmental and policy changes to increase physical activity. Evidence is needed to hone these recommendations and provide clear guidance to elected officials and other decision makers who are setting the course for our future built environment and policies. It is only through the solid understanding of critical environmental factors and the evaluation of environmental and policy change on physical activity that our ‘interventions’ will move beyond just influencing the motivated few to reach and facilitate the behavior change of the inactive many.