Psychophysiological Effects of Green Exercise in Outdoor Green vs. Indoor Control

NCT07379164 | Completed

• 1 other identifier: WTU-IRB-2025-0113
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

Brief Summary

Core Purpose: Researchers want to learn if walking in an outdoor green environment helps people recover from mental tiredness and stress better than walking indoors. This study investigates how a 30-minute walk in an outdoor green setting affects the mind and body compared to a 30-minute walk on a treadmill in a room without windows. The Study Process: The study included 80 healthy young adults between the ages of 18 and 35. Researchers randomly split the participants into two groups.

1. 1.The Outdoor Green group: Participants walked for 30 minutes on a path in an outdoor green environment.
2. 2.The Indoor Control group: This group walked for 30 minutes on a treadmill in a windowless room.
3. 3.Information Harvesting: Researchers used a new tool called the Nature Sensory Sensitivity Index (NSSI). This measures how well participants notice and "capture" sensory details from their surroundings, like the sounds of birds or the textures of plants.
4. 4.Restorative Feelings: Using the Perceived Restorativeness Scale (PRS), participants reported if they felt the environment helped them "get away" from daily stress and if the setting was interesting or beautiful.
5. 5.Overall Mood Changes (POMS TMD): Researchers used the Profile of Mood States (POMS) to calculate a Total Mood Disturbance (TMD) score. This helps show if participants feel less tense, angry, or tired, and more energetic after the walk.
6. 6.Connection to Nature (NR): Researchers measured each participant's Nature Relatedness (NR). This describes how much a person naturally feels connected to the natural world, which may influence how much they benefit from the green walk.
7. 7.Attention and Thinking: Participants performed a "Digit Span Task" (repeating sequences of numbers) to test if their focus improved.
8. 8.Physical Stress: The study used objective markers, including salivary cortisol (a stress hormone) and heart rate variability (a measure of how the nervous system relaxes).

Conditions

Psychological Stress; Mental Fatigue; Cognitive Dysfunction; Emotional Well-being; Healthy Volunteers

Keywords

Green Exercise; Nature-based Interventio; Attention Restoration Theory; Psychophysiological Restoration; Urban Health

Outcome Measures

Primary Outcomes (1)

• Change in Profile of Mood States - Total Mood Disturbance (ΔTMD)

  The POMS TMD is a self-report scale consisting of 6 subscales: Tension, Depression, Anger, Fatigue, Confusion, and Vigor. Each item is rated on a 5-point scale (0 = Not at all to 4 = Extremely). The TMD score is calculated as: (Tension + Depression + Anger + Fatigue + Confusion) - Vigor. The final outcome (ΔTMD) is the difference between the post-intervention TMD score and the pre-intervention (baseline) TMD score \[ΔTMD = TMD (Post) - TMD (Pre)\]. TMD scores range from -120 to 120. A larger negative ΔTMD value indicates a greater reduction in negative emotions and more significant psychological restoration.

  From Baseline (Pre-test) to 30 minutes post-intervention (Post-test)

Secondary Outcomes (5)

• Nature Relatedness (NR)

  Baseline (T0, before intervention)

• Nature Sensory Sensitivity Index (NSSI)

  Immediately after the 10-minute intervention (T1)

• Change in Perceived Restorativeness Scale (ΔPRS)

  From Baseline (T0) to Immediately after the 10-minute intervention (T1)

• Change in Total Digit Span Score (ΔDigit Span)

  From Baseline (T0) to immediately after the 30-minute intervention (T2)

• Change in Self-Esteem (ΔSelf-Esteem)

  From Baseline (T0) to immediately after the 30-minute intervention (T2)

Other Outcomes (2)

• Change in Heart Rate (ΔHR)

  From Baseline (T0) to immediately after the 30-minute intervention (T2)

• Change in Salivary Cortisol (ΔCortisol)

  From Baseline (T0) to immediately after the 30-minute intervention (T2)

Study Arms (2)

Outdoor Green Group

EXPERIMENTAL

Participants in this arm perform a standardized 30-minute walk at a moderate pace along a pre-defined route in an outdoor green enviroment. This arm focuses on the effects of exposure to natural environmental stimuli.

Behavioral: Outdoor Green Group

Indoor Control Group

ACTIVE COMPARATOR

Participants walk on a treadmill at a fixed moderate speed (4.0-5.5 km/h) with a 1% incline. This specific incline is used to compensate for the lack of air resistance indoors and to more accurately match the physiological energy expenditure of outdoor ground walking.

Behavioral: Indoor Control Group

Interventions

Outdoor Green Group BEHAVIORAL

Participants perform a supervised 30-minute walk at a moderate pace (4.0-5.5 km/h) along a pre-defined 2.5 km loop trail within a suburban forest park. The environment is characterized by high canopy cover (\>60%) and diverse natural vegetation. To ensure consistency, all sessions are conducted under stable weather conditions (Temperature: 20-26°C; Humidity: 40-60%). Participants walk individually to prevent social interaction, ensuring the restorative experience is derived solely from the individual-nature interaction.

Outdoor Green Group

Indoor Control Group BEHAVIORAL

Participants perform a 30-minute walk on a treadmill in a windowless indoor laboratory. To ensure consistency with the outdoor environment, the laboratory is climate-controlled with a temperature range of 20-26°C and humidity of 40-60%. The treadmill is set to a fixed moderate speed (4.0-5.5 km/h) with a 1% incline. The 1% incline is specifically applied to compensate for the lack of air resistance indoors and to accurately match the physiological energy expenditure and biomechanical demands of outdoor ground walking. The laboratory walls are neutral-colored to eliminate visual nature stimuli.

Indoor Control Group

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy adults aged 18 to 30 years.
• University students or individuals with equivalent educational background.
• Normal or corrected-to-normal vision and hearing.
• Willingness to comply with all study procedures and sign the informed consent form.

You may not qualify if:

• Physical Health: History of cardiovascular disease, respiratory illness, or chronic pain that may affect Heart Rate Variability (HRV).
• Mental Health: Diagnosis of clinical depression, anxiety disorders, or other psychiatric conditions.
• Substance Use: Current smokers or individuals with a history of alcohol or drug abuse.
• Medication: Recent use of any medications that affect the autonomic nervous system or endocrine function (e.g., steroids, beta-blockers, or hormonal medications) within the past month.
• Cognitive/Physical Impairment: Any disability that prevents walking for 30 minutes or completing the Digit Span cognitive task.

Sponsors & Collaborators

• Lincoln University College: lead
• Wuhan Technical University: collaborator

Study Sites (1)

Wuhan Technical University

Wuhan, Hubei, 430074, China

Location

MeSH Terms

Conditions

Stress, Psychological; Mental Fatigue; Cognitive Dysfunction

Condition Hierarchy (Ancestors)

Behavioral Symptoms; Behavior; Fatigue; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Cognition Disorders; Neurocognitive Disorders; Mental Disorders

Study Officials

• Sheng Yan

  Wuhan Technical University

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Doctoral Researcher

Model Details: This is a randomized, two-arm, parallel-group controlled trial. Participants are randomly assigned to either the Outdoor Green group or the Indoor Control group with a 1:1 allocation ratio. Each participant stays in their assigned group throughout the study duration and completes a standardized 30-minute walking task in their respective environment (an outdoor forest park versus an indoor laboratory).

Study Record Dates

• First Submitted: January 23, 2026
• First Posted: January 30, 2026
• Study Start: March 1, 2025
• Primary Completion: May 1, 2025
• Study Completion: December 15, 2025
• Last Updated: January 30, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)