Walking Green: Developing an Evidence-base for Nature Prescriptions

NCT03442998 | Completed

• 1 other identifier: 1703S09101
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Stress; Attention

Outcome Measures

Primary Outcomes (9)

• Change in Heart Rate Variability

  High frequency heart rate variation using ambulatory heart rate monitors (milliseconds).

  Measurements will be made at baseline one-week before the first walk, immediately before and after each walk, and within three days following the third walk of each condition (nature vs suburban).

• Change in Blood Pressure

  Blood pressure (mmHg) using a standard blood pressure cuff.

  Measurements will be made at baseline, immediately before and after each walk of each condition (nature vs suburban).

• Change in Cortisol Dynamics

  Diurnal cortisol dynamics measured by salivary cortisol (ug/dl), as the normal drop in cortisol during the day is attenuated by exposure to chronic stress.

  Measurements will be made before each walk of each condition (nature vs suburban).

• Change in Cytokine Blood Concentration

  Pro- and anti-inflammatory cytokine concentrations in blood (pg/mL), as stress typically induces an inflammatory response. Blood samples are collected by pricking the subject's finger-tip, collecting drops of blood on Protein SaverTMpaper (Whatman) and then drying the blood spots. The dried blood spots (DBS) are frozen and stored until assayed.

  Measurements will be made before each walk of each condition (nature vs suburban).

• Change in Attention restoration

  The Backward Digit Span test is one of the oldest tests used to evaluate working memory and is used to assess capacity to direct attention (i.e., attention restoration).

  Measurements will be made at baseline one-week before the first walk, immediately before and after each walk, and within three days following the third walk of each condition (nature vs suburban).

• Change in CESD

  CESD: Stress is strongly associated with depression. To measure depressive symptoms we will use the Center for Epidemiological Studies Depression Scale (CESD). Scores are determined by summing the participants' answers to all 20 items from 1 ("less than 1 day") to 4 ("5-7 days") pre- and post-walk in each intervention location (nature vs suburban).

  Measurements will be made at baseline, immediately before and after each walk of each condition (nature vs suburban).

• Change in PANAS

  PANAS: Stress is associated with decreased positive and increased negative affect (mood). We will measure affect using the Positive and Negative Affect Scale (PANAS). Scores are determined by summing the participants' answers to all 20 items from 1 ("very slightly or not at all") to 5 ("extremely") pre- and post-walk in each intervention location (nature vs suburban).

  Measurements will be made at baseline, immediately before and after each walk of each condition (nature vs suburban).

• Change in STAI

  Anxiety: Stress is associated with increased levels of anxiety. Anxiety will be measured using the State and Trait Anxiety Inventories (STAI). Scores are determined by summing the participants' answers to all 20 items from 1 ("not at all") to 4 ("frequently so") pre- and post-walk in each intervention location (nature vs suburban).

  Measurements will be made at baseline, immediately before and after each walk of each condition (nature vs suburban).

• Change in Perceived stress

  Perceived stress: Cohen's perceived stress scale (PSS) will be used to measure the extent to which subjects assess the events and situations in their lives to be stressful. Scores are determined by summing the participants' answers to all 10 items from 1 ("never") to 4 ("very often") pre- and post-walk in each intervention location (nature vs suburban).

  Measurements will be made at baseline, immediately before and after each walk of each condition (nature vs suburban).

Study Arms (2)

Suburban

OTHER

Study participants will wall on a suburban sidewalk setting for 50 minutes.

Other: Suburban walk

Nature

OTHER

Study participants will wall on a nature path setting for 50 minutes.

Other: Nature walk

Interventions

Suburban walk OTHER

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).

Suburban

Nature walk OTHER

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).

Nature

Eligibility Criteria

• Age: 35 Years - 59 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age 35 to 59
• No contraindications to physical activity
• No major chronic diseases or specific medications that would contraindicate exercise or potentially blunt heart rate variation during exercise

You may not qualify if:

• Cardiovascular disease medication
• Arthritis
• Steroids
• Certain blood pressure medications
• Diabetes
• Cancer
• Self-reported depression or anxiety / taking medication for depression or anxiety,
• Outside age range
• Inability to follow schedule including travel to arboretum
• Exceeding physical activity recommendations (250 minutes per week)
• Contraindications to walking

Sponsors & Collaborators

• University of Minnesota: lead

Study Sites (1)

Minnesota Landscape Arboretum

Chaska, Minnesota, 55318, United States

Location

Study Officials

• Mark A Pereira, PhD

  University of Minnesota

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 19, 2017
• First Posted: February 22, 2018
• Study Start: July 14, 2017
• Primary Completion: April 1, 2019
• Study Completion: April 1, 2019
• Last Updated: November 1, 2019

Record last verified: 2019-10

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)