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

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. The Outdoor Green group: Participants walked for 30 minutes on a path in an outdoor green environment.
2. The Indoor Control group: This group walked for 30 minutes on a treadmill in a windowless room.

What is Being Measured: To understand how the environment helps the brain recover, researchers used a "Sensory-to-Appraisal" model to measure several factors.

1. 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.
2. 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.
3. 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.
4. 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.
5. Attention and Thinking: Participants performed a "Digit Span Task" (repeating sequences of numbers) to test if their focus improved.
6. 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).

Why This Matters: The goal of this research is to see if actively noticing an outdoor green environment (sensory harvesting) is the "key" that unlocks mental recovery. By comparing the Outdoor Green group with the Indoor Control group, this study helps us understand why nature is good for public health and how to design better spaces for stress relief.

Conditions

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

Interventions

BEHAVIORAL

Outdoor Green Group

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.

BEHAVIORAL

Indoor Control Group

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.

Sponsors & Collaborators

• Wuhan Technical University

  collaborator UNKNOWN

• Lincoln University College

  lead OTHER

Principal Investigators

• Sheng Yan · Wuhan Technical University

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

30 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-03-01

Primary Completion

2025-05-01

Completion

2025-12-15

Countries

• China

Study Locations