Research: Physical Activity, Obesity and Health

The Journal of the American Medical Association reported that obesity has doubled among children and quadrupled among adolescents over the past 30 years, and more than one-third of children or adolescents in 2012 were overweight or obese (Ogden et al., 2014). These children are at an increased risk for developing health problems such as heart disease, diabetes, cancer, and hypertension as adults. The Centers for Disease Control and Prevention reported that overweight and obesity are leading cancer risk factors, and that 40 percent of all cancers diagnosed are associated with overweight and obesity (2017).

According to the 2012 National Health and Nutrition Survey, only one-quarter of youth ages 12-15 engage in at least 60 minutes of moderate-to-vigorous physical activity each day, as recommended by the Physical Activity Guidelines for Americans (Fakhouri et al., 2014). Among children, regular physical activity has been strongly associated with improved cardiorespiratory and muscular fitness and metabolic health, better bone health, and weight maintenance and energy balance, with greater benefits for participating in physical activity more often, longer, or at higher intensity (Duncan et al., 2016; Ward et al., 2015; US DHHS, 2008). Only half of American adults achieve recommended levels of physical activity (Ussery et al., 2017). There is a gender gap in physical activity levels, whereby women and girls are less likely than men and boys to attain recommended physical activity levels (Althoff et al., 2017; Ward et al., 2015).

Activity levels for many children have declined, due in part to a built environment that is unsafe for walking and bicycling, reduced physical education in school, and increased popularity of sedentary leisure-time activities. Safe Routes to School can create environmental, policy, and behavioral changes that increase physical activity and promote the health of both children and adults.  Articles summarized in this section address the overall health benefits of physical activity, specifically walking to and from school, as well as the impact that increased physical activity opportunities have on current obesity and health trends in the US.

Research Highlights:

  • Research demonstrates that children who walk or bicycle to school have higher daily levels of physical activity, lower body mass index and waist circumference, and better cardiovascular fitness than do children who do not actively commute to school (Mendoza et al., 2011; Davison, et al., 2008; Østergaard et al., 2012).
  • Two small lifestyle changes – a small increase in physical activity (walking an additional 2000 steps/day) and a small change in diet (eliminating 100 kcal/day) – help address childhood obesity by preventing excess weight gain (Hill, et al., 2007).
  • One study suggests that a 5% increase in neighborhood walkability is associated with 32.1% more minutes devoted to physically active travel and about one-quarter point lower BMI (0.228) (Frank, et al., 2006).
  • Children who walk to school get three times as much moderate to vigorous physical activity during their walk to school than during recess (Cooper et al., 2010). Children walk more when they live on more walkable routes with more open green space and less exposure to road traffic (Gallimore et al., 2011; Rahman, et al., 2011; Lamber et al., 2009).
  • Implementation of Safe Routes to School initiatives like Walking School Buses have demonstrated improved rates of walking to school, increased daily moderate-to-vigorous physical activity, and decreased overweight and obesity (Quarles, 2012; Mendoza et al., 2011; Mori et al., 2012; Kong et al., 2010).
  • Living in a walkable community has been associated with reduced prevalence of adolescent overweight and obesity (Slater et al., 2013).
  • Perceptions of safety and attractiveness impact a neighborhood’s walkability (Project for Public Space, 2016; Ussery et al., 2017).  
  • There are gender, racial, and class disparities in how much people walk. Compared to affluent and mostly white neighborhoods, neighborhoods with residents of low socioeconomic status and minority backgrounds are perceived as less attractive and safe because of crime (Ussery et al., 2017).   
  • Investing in bike lanes is an investment in public health: People bike more when the built environment supports bicycling by including bike lanes, bike racks, and traffic calming (Dill et al., 2013; Hipp et al., 2013; Winters et al., 2016).
  • In addition to more bike infrastructure and road engineering improvements to make bicycling safer, bicycle education is important (Pion et al., 2016).
  • US metro areas with greater multi-modal transportation options (i.e., walking, bicycling, public transit) have better public health outcomes: People make healthier lifestyle choices, have more quality leisure time, exercise more, have lower obesity rates, and live longer (Meehan et al., 2017; Frederick et al., 2017).

This study assesses the effects of interventions to promote walking in individuals and populations by conducting a systematic review of published and unpublished reports in any language identified by searching 25 electronic databases, by searching websites, reference lists, and existing systematic reviews, and by contacting experts.


Two small lifestyle changes, as promoted by the America on the Move initiative, in diet (to eliminate 100 kcal/day) and physical activity (to walk an additional 2000 steps/day), could be useful for addressing childhood obesity by preventing excess weight gain in families.


National estimates suggest that 14%-19% of children walk to school while state and local estimates suggest that 4% to 20% of children walk to school.


This study examines the relationship between relative weight and school attendance among 1,069 fourth to sixth graders from nine elementary schools in the inner city of Philadelphia, PA.


Financially disadvantaged populations are more likely to live in communities that do not support healthy choices. This paper investigates whether certain characteristics of the built environment are associated with obesity or coronary heart disease (CHD) risk among uninsured low-income women.


By quantifying the magnitude of energy imbalance responsible for the increase in body weight among US children, this study looks to provide salient targets for population intervention.


In 2003-2004, 17.1% of US children and adolescents were overweight.


This article examines single-use, low-density land use patterns and reports that a 5% increase in neighborhood walkability is associated with:


This study examines the link between childhood overweight status and school outcomes (academic achievement, teacher reported internalizing and externalizing behavior problems, social skills, approaches to learning, school absences, and grade repetition) between kindergarten entry and end of the third grade.


This article reviews what is known about the built environment and its relationship to physical activity.