Understanding environmental influences on walking

Abstract

Background

Understanding how environmental attributes can influence particular physical activity behaviors is a public health research priority. Walking is the most common physical activity behavior of adults; environmental innovations may be able to influence rates of participation.

Method

Review of studies on relationships of objectively assessed and perceived environmental attributes with walking. Associations with environmental attributes were examined separately for exercise and recreational walking, walking to get to and from places, and total walking.

Results

Eighteen studies were identified. Aesthetic attributes, convenience of facilities for walking (sidewalks, trails); accessibility of destinations (stores, park, beach); and perceptions about traffic and busy roads were found to be associated with walking for particular purposes. Attributes associated with walking for exercise were different from those associated with walking to get to and from places.

Conclusions

While few studies have examined specific environment–walking relationships, early evidence is promising. Key elements of the research agenda are developing reliable and valid measures of environmental attributes and walking behaviors, determining whether environment–behavior relationships are causal, and developing theoretical models that account for environmental influences and their interactions with other determinants.

Introduction

Promoting higher levels of participation by adults in regular, moderate-intensity physical activity is a public health priority.1, 2 Recent evidence from Australia suggests that, although public campaigns and other initiatives to increase participation have been underway for more than 10 years, population levels of physical activity have been static and may have declined in some groups.3 There is a strong case that substantial and long-lasting environmental and policy initiatives are an important opportunity for making physically active choices easier and more realistic choices.4, 5, 6 If advocacy for this public health agenda is to be pursued with confidence, research is needed to determine whether environmental changes (such as providing cycle paths and walkways, or public outdoor recreational settings) do increase the likelihood of more active behavioral choices. However, there are significant conceptual and methodologic challenges in identifying how such physical-environment factors might act to influence such choices.7 Conceptually, there is a plausible case that environmental influences can play a direct role in shaping habitual behavior patterns. Experimental evidence from several behavioral domains identifies circumstances in which direct environmental influence can be a stronger determinant of behavioral choice than are cognitively mediated influences.8, 9 Because cognitive social theories have been a predominant influence on behavioral studies of physical activity,10, 11, 12, 13 the field has been shaped by assumptions that choices to be active or inactive are conscious and deliberate—that is, consequent upon attitudes, intentions, self-efficacy, and other cognitive mediators of behavioral change.11, 12 Social cognitive models do, however, identify a strong role for environmental influences under some circumstances. Bandura14 has argued that when behavior is strongly facilitated or constrained by attributes of the environment in which it takes place (and plausibly this is often likely for physical activity), direct environmental influences would be the predominant class of determinants.

Studies of environment–activity relationships, if they are to be of practical use in public health policy, ought to focus on the environmental influences that may determine particular behavioral choices.4, 8, 9, 15 In the context of the public health goal to increase regular, moderate-intensity physical activity, the behavior of most relevance is walking. The public health policy literature has identified walking as the physical activity behavior of adults that should be most amenable to influence.12, 16 Walking is also the most commonly reported physical activity behavior.16, 17 Thus, there is a strong conceptual and practical case for public health research on the environmental determinants of physical activity to focus on the particular behavior of walking.

Humpel et al.18 reviewed the evidence for environmental influences on physical activity generally. They found that both perceived and objectively determined environmental attributes (particularly aesthetics, convenience, and access) were associated with an increased likelihood of physical activity. Adopting a more specific focus, Saelens et al.19 synthesized the findings of studies from transportation and urban design and planning research on factors related to walking and cycling for transportation purposes. Much of the transportation literature focuses on vehicular travel. However, human-powered modes of travel such as walking and cycling have also been examined in many studies. Given that most nonwork trips are within walking or cycling distance, findings from this closely related area of research are helpful in identifying objectively measured environmental attributes (particularly mixed land use, residential density, and intersection density19) that are relevant to the choice to walk. A conceptual model of the specificity of environmental correlates of walking and cycling resulted from this review.19 Environmental and policy initiatives to increase physical activity4 must be informed by such conceptual models and also by a strong body of evidence on the environmental attributes that are related to such particular active behavioral choices.

Here, studies from the public health research literature specifically addressing the environmental correlates of walking are reviewed. The term “correlates” was used advisedly,7, 11 given that much of the evidence available is from studies using cross-sectional designs. Specifically, the focus was on relationships of perceived and objectively assessed environmental attributes with the walking behaviors of adults. The evidence was evaluated on specific environmental attributes associated with subcategories of walking behavior—walking for exercise or recreation, walking to get to and from places, and total walking.