Journal Issue: Childhood Obesity Volume 16 Number 1 Spring 2006
The Built Environment and Physical Activity
Children themselves know that characteristics of the built environment affect how active they can be: physical activity is welcome in certain places and is difficult, discouraged, or even prohibited in others. Buildings, transportation infrastructure, elements of land use and community design, and recreational facilities, such as parks and trails, all affect citizens' physical activity.
Health and recreation researchers have focused on the link between access to recreation facilities and children's recreational physical activity. A handful of studies have shown what common sense would also suggest: children and adolescents with access to recreational facilities and programs, usually near their homes, are more active than those without such access.4 Adolescent girls' physical activity is related to the proximity of recreational facilities.5 The more often young adolescents use recreational facilities, the greater their total physical activity, with parks and the neighborhood most important for boys and with commercial facilities and the neighborhood most important for girls.6 Preschool children are more active when there are more places nearby where vigorous play is welcome and when they spend more time in those places.7 Three studies of preschool children using direct observation report that being outdoors is the strongest correlate of the children's physical activity.8
There are some contrary findings. Two studies, for example, reported no significant links between physical activity and such variables as environmental barriers, access to supervised programs, and distance to parks.9 Both studies, however, were based on parental reports rather than direct observation. Another study of young children found no relation between their proximity to playgrounds and being overweight.10
To sum up, the broad conclusions of existing studies are consonant with a review of research on adults, which consistently linked physical activity with both access to and the attractiveness of recreational facilities and programs.11
If further research confirms the associations between access to facilities and youth physical activity, the policy implication is clear: all children need places where they can be physically active on a regular basis. The most important such places appear to be outdoors and in the neighborhood and include both public parks and commercial facilities. Because children engage in such a variety of activities and because their recreational needs vary widely by age, providing many different types of facilities is a promising policy objective.
How accessible facilities are depends on how close they are to children's homes or schools, how costly they are to use, and how easily they can be reached. At least two U.S. studies found fewer parks, sports fields, fitness clubs, and trails in low-income neighborhoods than in more affluent ones, suggesting that low-income youth may face barriers to physical activity.12 Interestingly, low-income neighborhoods had relatively fewer free than pay-for- use facilities, suggesting the possible influence of community tax bases and related spending policies. Because the distribution of facilities is likely to vary across cities, researchers should examine more locations, focusing on the quality of facilities as well as access.
Although market forces primarily govern the distribution of private recreational facilities, cities and states could enact tax-based incentives, similar to those often used to spur economic and business development, to locate private facilities in low-income neighborhoods. Publicly funded parks and trails generally garner strong support.13 Some 90 percent of a national sample of U.S. adults supported using local government funds for walking and jogging trails, recreation centers, and bicycle paths. People may support spending for recreational facilities because they believe public open space improves their quality of life, but building more and better public recreational facilities could also promote youth physical activity.14 Also health care savings could conceivably offset the government's costs of building such facilities. Several cities have recently taken steps to improve their parks. Voters in Los Angeles have approved major bond issues in recent years to upgrade urban parks. Denver's public schools have approved converting school playgrounds to community parks. And public-private partnerships in metropolitan Atlanta have accelerated the pace of building a regional network of mixed-use walking and cycling paths.15
Transportation and urban planning researchers have for several decades been examining how a community's design encourages (or discourages) its citizens to walk and cycle for transportation (rather than for recreation), though until recently health professionals were unfamiliar with the reseachers' work.16 Though the original research focus was directed toward reducing traffic congestion and improving air quality, the findings have direct implications for physical activity.
Before the middle of the twentieth century, communities were designed to support convenient pedestrian travel for common activities, such as shopping and going to school. Indeed, many U.S. towns and cities developed before automobile use became widespread and were pedestrian oriented by necessity. These “traditional” neighborhoods are characterized by mixed land use, connected streets, and moderate to high density. Homes, stores, employment centers, and government services are located near one another, often with multiple uses in the same multistory building. Streets are laid out in a grid pattern that creates high levels of connectivity and offers pedestrians direct routes from place to place. High residential density, with a preponderance of multifamily dwellings, makes local stores financially viable. For obvious reasons, these traditional designs are termed “walkable.”
As the twentieth century progressed and America's suburbs began to grow, however, a variety of policies were set in place to optimize automobile travel. Different forms of land use were separated by zoning codes, so homes and stores were no longer within walking distance. The street network within residential areas was disconnected, and long blocks and many cul-de-sacs made pedestrian travel all but impossible. Low-traffic residential streets fed into multilane, high-speed arterial streets that presented serious barriers and dangers to pedestrians. Because the design of suburbs essentially requires the use of automobiles for all trips, such communities are often described as “unwalkable,” especially for transportation.
Many studies have examined components of walkability or compared walking and cycling for transportation in high- and low-walkable neighborhoods. They consistently show more walking and cycling for transportation in walkable neighborhoods.17 Recent studies using objective measures of total physical activity have found that residents of high-walkable neighborhoods get one hour more of physical activity each week and are 2.4 times more likely to meet physical activity recommendations than residents of low-walkable neighborhoods.18 Recent reports from the Transportation Research Board and Institute of Medicine and the Centers for Disease Control's “Guide to Community Preventive Services” conclude that the design of communities is linked with physical activity, though causality cannot be established because of the self-selection problem already noted.19
Though most such research has not focused on children, several studies suggest that young people would be more likely to walk to nearby destinations in traditional neighborhoods. Kevin Krizek, Amanda Birnbaum, and David Levinson have argued that community design is relevant to youth physical activity and have recommended that researchers examine the specific destinations, activities at those destinations, and travel modes that are most common for children.20 An Australian study found that the way people perceive a neighborhood environment can affect the extent to which children in that neighborhood walk and cycle to destinations.21 Perceptions of heavy traffic, a lack of public transit, a lack of street-crossing aids, the need to cross several roads, and a lack of nearby recreational facilities were all linked to lower rates of active transportation. One study of adolescents found that boys were more active when they lived near pedestrian-oriented shopping areas.22 In an unexpected finding, girls were more active when streets were less connected, suggesting that low-traffic residential streets and cul-de-sacs may be play areas for some young people.23 Researchers should also look into how community design variables may operate differently for children, adolescents, and adults.
Several investigators have examined how community design relates to the weight status of adults. Four studies have documented lower body mass index (BMI) or reduced risk of overweight and obesity in people living in more walkable areas.24 The one study focusing on adolescents, however, found no link between neighborhood environment and BMI, so it would be premature to draw any final conclusions.25
Walking and cycling to school are of particular interest because both require substantial energy expenditures on a daily basis.26 And, indeed, studies have found that children who walk to school are more physically active than those who travel to school by car, though we could locate none linking walking with weight status.27 However, active commuting rates are low, ranging from only 5 to 14 percent.28 Low-walkable suburban development patterns, such as the lack of sidewalks, long distances to schools, and the need to cross busy streets with fast-moving traffic, appear to create barriers to active commuting to school.29
The simple fact is that more children walk to school in neighborhoods with sidewalks.30 An evaluation of the Marin County, California, Safe Routes to Schools program that combined promotional activities with built environment changes—more sidewalks and improved street crossings—found a 64 percent increase in walking and a 114 percent increase in cycling to school.31 And an evaluation of statewide investments in sidewalks, crosswalks, and bike lanes in ten California schools found that 15 percent of parents of children who passed the improvements on their way to school reported their children walked or cycled more.32 The Robert Wood Johnson Foundation's Active Living Leadership program has documented initiatives across the United States at the city, county, and state levels that are designed to create built environments that make it easy for people to be physically active for transportation and recreation purposes.33
With pedestrian injuries a major cause of childhood injuries and deaths, parents are understandably concerned about traffic safety.34 Priority should thus be placed on designing roads, sidewalks, and crosswalks that make it safe for children to walk and cycle. The need for greater investment is clear. Rates of pedestrian death and injury are vastly higher in the United States than in Western European countries such as Germany and the Netherlands, where extensive networks of protected cycling and pedestrian lanes, along with laws that make drivers rather than pedestrians or cyclists liable in accidents, have dramatically improved pedestrian safety.35 It is true that the development of safe sidewalks, crosswalks, and bike lanes will not increase active commuting among children whose homes are too distant from their schools or who are driven to school to suit their parents' work schedules. However, the evidence suggests that rates of active commuting can be modified through environmental interventions.
Sedentary recreational behaviors, such as watching television and videos, using computers, and playing video games, are important parts of young people's daily lives. They are also risk factors for obesity in youth, and reducing such behaviors is another strategy for preventing childhood obesity.36 Research is beginning to document connections between the built environment and sedentary behaviors. Without safe places to play near home, for example, children may spend more time being inactive indoors. Likewise, heavy traffic reduces the likelihood of children's walking and may thus keep children indoors, where they remain sedentary.37 Time spent riding in a car is associated with a risk of overweight in adults, and residents of low-walkable neighborhoods spend more time driving, so community design is likely to have a similar effect on children.38 These and other hypothesized associations between children's sedentary behavior and community design need to be more closely examined.
Strategies for Change
Making the multiple environmental changes supported most consistently by the limited but rapidly expanding evidence will require leadership from many sectors.39 The strongest evidence links access to recreational facilities and programs with child and adolescent physical activity. Recreation departments in local and state governments are a primary interest group for intervention in this area. They could promote physical activity among youth of all ages by designing and outfitting parks to provide diverse opportunities for popular physical activities, ensuring equitable distribution of recreational facilities, and emphasizing physical activity over other programs. Because achieving these goals may require increased funding, government leaders could be targeted for advocacy. The Cleveland Parks Department could be a model for other cities. As another possible model, the National Recreation and Park Association has partnered with the National Heart, Lung, and Blood Institute to develop, evaluate, and disseminate the Hearts N' Parks program across the nation.40
Commercial groups, such as dance and martial arts studios, and community organizations, such as youth sports leagues, churches, and after-school programs, all manage or interact with places for youth physical activity. Such groups could boost physical activity in children of all skill and income levels. Youth groups could use these facilities for their social and recreational programs, using sliding-scale fees to increase access for low-income youth. Increasing physical activity opportunities for low-income youth is a priority, because these children have few options. Providing tax breaks for commercial physical activity providers, such as dance studios and health clubs, to build facilities in low-income areas is a strategy worth exploring.
Since 1990, the federal government has made transportation funds available for pedestrian and bicycling infrastructure. State and local transportation funds support sidewalks, trails, traffic calming, and crosswalks. Safe Routes to Schools construction funding is available from the U.S. Department of Transportation and from the transportation departments of California and a few other states. Organized advocacy, however, may be needed to shift priorities within transportation departments to ensure adequate funding of pedestrian and bicycle facilities.
Creating the mixed-use, highly connected communities found to be associated with more physical activity requires changes in zoning codes and development regulations. Such organizations as Congress for the New Urbanism and Smart Growth America are promoting these reforms.41 To improve the comfort and safety of pedestrians and bicyclists, changes are needed to improve road design guidelines. The “complete streets” concept would make all streets suitable for pedestrians, cyclists, and motorists.42 Subsequent research must determine whether walkable neighborhoods and complete streets are health-promoting for youth as well as adults. However, many initiatives are under way nationwide to advocate for policy changes that will make environments more supportive of physical activity. They should be carefully evaluated.