Quantifying the Relaxation Potential of Multisensory Nature Walk Experiences

Academic Collaboration

The project involved an international research team, including:

• INRS-EMT (Institut national de la recherche scientifique – Centre Énergie Matériaux Télécommunications), Montreal, Canada
• MuSAE Laboratory, led by Prof. Tiago H. Falk
• Federal University of Health Sciences of Porto Alegre (UFCSPA), Brazil
• Researchers: Marilia K. S. Lopes, Belmir J. de Jesus Jr., Marc-Antoine Moinnereau, Reza A. Gougeh, Olivier M. Rosanne, Walter Schubert, Prof. Alcyr A. de Oliveira Jr., Prof. Tiago H. Falk

Study Aim

The central question was whether adding realistic sensory cues—such as wind, temperature changes, scents and vibroacoustic feedback—to a virtual nature walk would produce:

• Higher self-reported relaxation compared to audio-visual VR alone
• Objective physiological signatures of reduced stress and increased parasympathetic activity
• Meaningful correlations between how relaxed people felt and how their bodies responded

Multisensory Features

• 360° immersive video displayed through a VR headset
• Spatial surround sound audio for environmental realism
• Olfactory stimulation with scents such as forest, earth, grass and ocean breeze
• Somatosensory feedback using fan systems for wind simulation
• Dynamic temperature modulation via integrated heating elements
• Vibroacoustic feedback using subwoofers beneath the seat

Why Multiple Senses?

The study builds on evidence that nature exposure works best when multiple senses are engaged:

• Scents and natural sounds can tap into limbic system circuits linked to calm and safety.
• Wind and temperature changes increase the sense of “being there” in the environment.
• Vibroacoustic cues add a subtle bodily component that supports embodied relaxation.

The SENSIKS booth makes it possible to standardise and repeat such experiences in laboratory and clinical settings.

Participants and Conditions

• 16 healthy adults (mean age around 27 years)
• Two experimental conditions:
• Audio-visual virtual nature walk (standard VR)
• Ultra-reality multisensory nature walk in the SENSIKS booth
• Counterbalanced order to control for sequence effects
• Short, structured exposures to minimise fatigue

After each condition, participants rated their level of relaxation using a standardised Relaxation Rating Scale.

Physiological Signals and Features

Participants wore two medical-grade devices throughout the sessions:

• BioHarness3 chest strap: electrocardiogram (ECG) and breathing rate/pattern
• Empatica E4 wristband: electrodermal activity (EDA), skin temperature and blood volume pulse (BVP)

The research team extracted more than 50 features across these signals, including heart rate variability components, EDA indices, respiratory metrics and temperature dynamics.

Subjective Relaxation

• Participants rated the multisensory condition as significantly more relaxing than the audio-visual condition.
• Relaxation Rating Scale scores were higher with p < 0.01.
• Qualitative feedback indicated that the combination of sights, sounds, smells and physical sensations felt closer to a real nature walk.

Physiological Markers of Relaxation

• Heart rate variability (HRV): increased high-frequency HRV, associated with parasympathetic activation and calm states.
• Electrodermal activity (EDA): reductions in low-frequency EDA components and lower variability, consistent with reduced sympathetic arousal.
• Blood volume pulse (BVP): changes compatible with cardiovascular relaxation.
• Several indices reached statistical significance (e.g., EDA standard deviation with p < 0.05).

Correlations Between Feelings and Physiology

• Heart rate variability features correlated with relaxation scores (e.g., r ≈ -0.41 for selected ECG-derived metrics).
• Breathing pattern characteristics (e.g., respiratory rate and variability) showed correlations in the range r ≈ -0.46 to -0.50.
• Electrodermal features yielded correlations around r ≈ 0.42 to -0.43, depending on the specific index.

These associations suggest that when people report feeling more relaxed in the SENSIKS booth, their nervous system activity reflects that state.

Implications for Mental Health Interventions

The convergence of subjective and physiological data indicates that multisensory VR can be used not only as an engaging experience, but also as a measurable intervention platform for:

• Stress and anxiety reduction programmes
• Complementary support in PTSD and trauma-related disorders
• Workplace or occupational health stress management
• Preventive mental health and relaxation training

The study does not replace established therapies, but it provides a research foundation for future clinical applications.