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).
Research
Physical Activity in US Youth Aged 12-15 Years

KEY TAKEAWAYS:

Only ¼ of US youth ages 12-15 met national physical activity guidelines in 2012, and levels of physical activity differ by gender and weight status.

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Physical Activity and Performance at School
A Systematic Review of the Literature Including a Methodological Quality Assessment

The purpose of this study is to describe the prospective relationship between physical activity and academic performance.

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Research Brief: Promoting Physical Activity through the Shared Use of School and Community Recreational Resources

Regular physical activity promotes important health benefits and reduces risk for obesity. 

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Commuting Distance, Cardiorespiratory Fitness, and Metabolic Risk

Limited evidence exists on the metabolic and cardiovascular risk correlates of commuting by vehicle, a habitual form of sedentary behavior.

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Leveraging the Health Benefits of Active Transportation
Creating an Actionable Agenda for Transportation Professionals

The authors are researchers at the University of North Carolina Highway Safety Research Center, Chapel Hil, North Carolina.  They provide a review of the health benefits of active transportation as a call to transportation planners to include health in the agenda for transportation planning, funding, and engineering considerations. 

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Commuting Distance, Cardiorespiratory Fitness, and Metabolic Risk

Limited evidence exists on the metabolic and cardiovascular risk correlates of commuting by vehicle, a habitual form of sedentary behavior. To examine the association between commuting distance, physical activity, cardiorespiratory fitness (CRF), and metabolic risk indicators.

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Energy Expenditure Associated With the Use of Neighborhood Parks in 2 Cities

Availability of public neighborhood parks is associated with physical activity. Little is known about how parks contribute to population energy balance. This study estimated energy expenditure associated with the use of neighborhood parks and compared energy expenditure by activity areas within parks and by neighborhood race/ethnicity and income.

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Increasing Physical Activity in Under-Resourced Communities Through School-Based, Joint-Use Agreements
Los Angeles County, 2010-2012

Few studies have examined how joint-use agreements between schools and communities affect use of school facilities after hours for physical activity in under-resourced communities. The objective of this study was to assess whether these agreements can increase community member use of these opened spaces outside of school hours.

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Is There an Association Between Gasoline Prices and Physical Activity? Evidence From American Time Use Data

A recent paper in the economics literature finds an inverse relationship between gasoline prices and obesity risk—suggesting that increased gasoline prices via higher gasoline taxes may have the effect of reducing obesity prevalence. This study builds upon that paper.

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Toward Environments and Policies that Promote Injury-Free Active Living
It Wouldn't Hurt

This article provides an overview of the evidence base concerning unintentional injuries associated with popular forms of physical activities for youth, and describes how injury prevention and child obesity professionals can work together to prevent injuries while promoting active lifestyles.