Walking Green: Developing an Evidence-base for Nature Prescriptions
Condition: Stress; Attention
Study type: Interventional

Summary: 
      The investigators hypothesize that walking on a nature trail will lead to greater reductions
      in stress and greater improvements in the capacity to direct attention as compared to walking
      on a suburban sidewalk.

      The effects of walking in these different locations will be measured using physiological and
      psychological outcomes. The study design is a randomized with-in person cross-over trial.
      Subjects will take six 50-minute walks, one walk per week for six weeks. Three walks will
      occur in the urban setting and three in the nature setting. The order of the conditions will
      be randomly assigned to each subject, so that half of the subjects will complete the urban
      walks first and half the subjects will complete the nature walks first. There will be a
      two-week washout period between the two sets of walks. Day of the week will be fixed within
      person, and walks will occur during the mild weather months. In the case of inclement
      weather, the weekly walk will be skipped and an additional week will be added to the
      schedule. Limiting the frequency to one walk per week maximizes feasibility of the protocol
      and minimizes training effects, with any training effects over time being handled primarily
      by randomization (condition order is balanced), but also in the statistical analysis.
    

Detailed description: 
      Suburban walks will be mapped out in clean, safe streets with sidewalks within 3 miles of the
      Arboretum, in Chaska, Minnesota. A loop covering approximately 1.25 miles will be mapped. At
      a usual walking speed of 20 minutes per mile, a subject will complete ~ 2 loops. Each walk
      will be timed so that walking speed can be included in the statistical analysis as an
      important covariate.

      Nature Walks will take place at the University of Minnesota Landscape Arboretum, which is
      part of the College of Food, Agricultural and Natural Resource Sciences at the University of
      Minnesota. The Arboretum features more than 1,215 acres of natural landscapes with over 12
      miles of trails. Subjects in this study will take their nature walks on the Green Heron Pond
      Trail and adjacent trails that can be connected to create a walking loop of ~1.25 miles, or
      an out-and-back course, matching the distance of the suburban walk. Heron Pond and its
      adjacent marsh and bog represent three naturally occurring ecosystems in Minnesota that are
      part of the state's geologic and landscape heritage. The bog trail passes through the most
      diverse ecotypes of any Arboretum hike. Oak woods, maple woods and the mosaic of intermingled
      wetlands along the boardwalk offer rich rewards for birders, school groups and families.

      The primary approach to the statistical analysis will be a repeated measures multivariable
      linear regression model. The outcomes will be the psychological and physiological measures of
      stress. The primary independent variable of interest is condition (suburban v. nature). The
      interaction of condition and time (week of the study) provides a formal test of intervention
      effects (differences between the urban and nature walks). That is, over the time course of
      the interventions, are there significant differences in the outcomes between the urban and
      nature walks? Covariates to be evaluated in the models as possible confounders include the
      order of the conditions (urban first v. nature first), age, gender, body mass index, and
      overall habitual physical activity. On an exploratory basis, the investigators will test
      whether these covariates also serve as modifiers of the intervention effect.
    

Intervention name(s): Suburban walk; Nature walk
Intervention type(s): Other; Other
Intervention description(s): Each subject is tested under the 'suburban' condition. We will compare the stress response and working memory response to walking in the two experimental conditions ((1)response to walking on a nature path and (2) response to walking on an urban sidewalk).; Each subject is tested under the 'nature' condition. We will compare the stress response and working memory response to walking in the two experimental conditions ((1)response to walking on a nature path and (2) response to walking on an urban sidewalk).
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Other