Effects of Brief Nature Exposure on Brain Functioning and Stress Reactivity

YONDER Study (Effects of Brief Nature Exposure on Brain Functioning and Stress Reactivity)

This study is focused on understanding the impact of time spent in nature (relative to an urban control) on stress, neural, and cardiac functioning in people experiencing high levels of stress, depression, and anxiety.

Study Overview

• Status: Recruiting
• Conditions: Stress (Psychology)
• Intervention / Treatment: Other: Nature vs. Urban walks

Detailed Description

Associations between urbanization and mental illness have long been recognized, but the mechanistic pathways underlying this association are not well understood and likely multifactorial. Reduced contact with nature may contribute to the increased psychopathology observed in urban environments.

Theories implicating attention restoration and stress reduction functions via cognitive control and reward brain networks have been proposed to explain how natural environments may decrease stress and promote mental health, particularly in individuals with high-stress loads who are at-risk for developing mental illness. However, most research examining nature's effects on mental health have been observational in design, leaving open questions about nature's effects on neural functioning. Well-controlled studies of brain responses to natural environments will inform stakeholders about potential cognitive and health benefits of nature, as well as guide development of clinical applications like parks prescriptions and nature-based behavioral interventions for individuals who may benefit. This team science grant will enable pilot data collection and a novel collaboration combining faculty expertise in pediatric nature-basedinterventions, clinical neuroscience of reward and motivation, electrophysiological biomarkers of psychiatric vulnerability and integrative healthcare. Further, our team will tap the policy and stewardship expertise of parks system leadership. This project's goal is to conduct a pilot clinical neuroscience study to establish a novel academic-community collaboration and support a larger project proposal to examine neurophysiological mechanisms underlying nature-based clinical interventions to improve mental health in individuals experiencing stress-based symptoms.

• Study Type: Observational
• Enrollment (Estimated): 20

Contacts and Locations

Study Locations

• United States
  • California
    • San Francisco, California, United States, 94122
      • Recruiting
      • University of San Francisco California OR San Francisco VA Medical Center
      • Contact: Susanna Fryer, PhD; Phone Number: 4155624334; Email: susanna.fryer@ucsf.edu
      • Contact: Annalise Jear, BA; Phone Number: 26358 4152214810; Email: Annalise.Jear@ucsf.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Individuals endorsing high stress levels will be recruited from the community and UCSF clinician outreach through flyer, media advertisements. Current or past depressive and anxiety disorders, if present, will be included due to their high prevalence and overlap with perceived stress.

Description

Inclusion Criteria:

• Meets cut-off for high level of perceived stress on PSS-10 during screening (>27 total score); Current or past depressive and anxiety disorders, if present on SCID-5 assessment, will be ncluded due to their high prevalence and overlap with perceived stress
• Normal, or corrected to normal, vision (due to the visual nature of the EEG tasks)
• If on psychotropic medication, stable regime for > 1 month

Exclusion Criteria:

• Major medical conditions with CNS sequelae (e.g., seizure disorders, multiple sclerosis, significant, uncontrolled cardiovascular pathology) Past or present neurological problems (including seizures and head trauma resulting in neurological or cognitive sequelae)
• IQ estimate <75 on the Test of Premorbid Functioning
• Current or past history of severe mental illness (e.g., bipolar schizophrenia spectrum disorder, or current or past history of substance use disorders

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Within-group study; individuals endorsing current high stress levels	Other: Nature vs. Urban walks; We will evaluate the impact of spending time in nature vs. an urban control on EEG-based measures of reward and attention and resting heart rate variability

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Brain functioning	EEG (neural) measures of attention and reward processing ; resting EEG (including frequency-based analyses of canonical frequency bands, e.g., gamma, beta, alpha, delta, theta) and event-related potential measures (reflecting attention, e.g, P300 and reward/affective processing, e.g., reward positivity, late positive potential).	~1 hour after walking condition
Heart Rate Variability	This measure reflect the variation in heart beat rate, over time. Specifically we will measure heart rate during the EEG recordings and calculate the RMSSD (Root Mean Square of Successive Differences) of heartbeat R-R intervals.	~ 1 hour after walking manipulaation

Collaborators and Investigators

• Sponsor: National Institutes of Health (NIH)

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2026
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): June 30, 2026

Study Registration Dates

• First Submitted: March 17, 2026
• First Submitted That Met QC Criteria: March 30, 2026
• First Posted (Actual): April 2, 2026

Study Record Updates

• Last Update Posted (Actual): April 2, 2026
• Last Update Submitted That Met QC Criteria: March 30, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: stress; nature; eeg; reward processing ; attention functioning
• Other Study ID Numbers: UCSF (Other Grant/Funding Number: UCSF Resource Allocation Program (RAP))

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: This is a small pilot study largely aimed at generating pilot data for a larger (NIH) application; the applications these data support will propose data sharing

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No