Effects of Forest Therapy on Physical and Psychological Parameters in the General Population - a Randomized Controlled Trial

May 27, 2025 updated by: Andreas Michalsen, Charite University, Berlin, Germany
In recent years, nature and forest therapy has increasingly become the focus of medical research. Recent scientific findings indicate overall positive effects of nature and forest therapy on physical and mental health. In Asia and Australia, it has already been implemented as a public health concept of prevention and health promotion. The aim of the project is to replicate the experience gained in Asia over the last three decades on the physical and psychological effects of nature/forest therapy in the context of the German forest and to investigate it further scientifically.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
120

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Germany
      • Berlin, Germany, 14109
        • Recruiting
        • Charité Hochschulambulanz für Naturheilkunde am Immanuel Krankenhaus
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 90 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

- Ability to Consent

Exclusion Criteria:

  • Serious acute or chronic illness
  • Immobility or limitation of mobility due to orthopedic, neurologic, or other medical causes
  • Participation in another study
  • Serious mental illness
  • Pregnancy and lactation.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
No Intervention: Waiting list
Experimental: Active forest therapy
Behavioral: Active forest therapy
Participants take part in a two-hour active clinical forest therapy in Berlin-Wannsee on two days (with a break day in between). In this setting, a trained clinical forest therapist teaches exercises on the perception of nature and the connection between nature and health.
Active Comparator: Passive forest therapy
Behavioral: Passive forest therapy
Participants take part in a two-hour passive clinical forest therapy in Berlin-Wannsee over two days (with a break day in between). In this setting, a trained clinical forest therapist will guide participants to various locations in the forest where participants can stay and let nature have its effect on them.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Profile of Mood States (POMS)
Time Frame: Change from baseline POMS score at 3 months
Change from baseline POMS score at 3 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Profile of Mood States (POMS)
Time Frame: Baseline, day 1, day 3, 1 week, 3 months
Baseline, day 1, day 3, 1 week, 3 months
Perceived Benefits of Nature Questionnaire (PBNQ)
Time Frame: Baseline, 1 week, 3 months
Baseline, 1 week, 3 months
Subjective Vitality Scale state (SVS-G state)
Time Frame: Baseline, day 1, day 3, 1 week, 3 months
Baseline, day 1, day 3, 1 week, 3 months
Complaint List (B-LR)
Time Frame: Baseline, 1 week, 3 months
Baseline, 1 week, 3 months
Perceive Stress Questionaire (PSQ)
Time Frame: Baseline, day 1, day 3, 1 week, 3 months
Baseline, day 1, day 3, 1 week, 3 months
Freiburger Fragebogen zur Achtsamkeit (FFA)
Time Frame: Baseline, 1 week, 3 months
Baseline, 1 week, 3 months
Hospital Anxiety and Depression Scale (HADS)
Time Frame: Baseline, 1 week, 3 months
The scale ranges from 0 to 3. Higher scores correspond to higher levels of anxiety and/or depression.
Baseline, 1 week, 3 months
Perceived Stress Scale (PSS)
Time Frame: Baseline, 1 week, 3 months
The scale ranges from 0 to 4. Higher scores correspond to higher levels of perceived stress.
Baseline, 1 week, 3 months
Allgemeine Selbstwirksamkeit Kurzskala (ASKU)
Time Frame: Baseline, 1 week, 3 months
The scale ranges from 1 to 5. Higher scores correspond to better outcomes.
Baseline, 1 week, 3 months
State-Trait Anxiety Inventory (STAI)
Time Frame: Baseline, day 1, day 3, 1 week, 3 months
The scale ranges from 1 to 8. Higher scores correspond to higher levels of anxiety (after recoding three inverted items).
Baseline, day 1, day 3, 1 week, 3 months
PROMIS Scale v1.2 - Global Health
Time Frame: Baseline, 1 week, 3 months
The scale ranges from 1 to 5, where 1 is the lowest level and 5 is the highest level. Higher scores reflect better functioning.
Baseline, 1 week, 3 months

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Heart Rate Variability (HRV)
Time Frame: Baseline, 1 week
24h measuring by Faros 180
Baseline, 1 week
Qualitative interviews
Time Frame: 1 week and 8 weeks after inclusion
Qualitative assessment will be carried out in qualitative interviews in 20 patients participating in the study. The interviews will be recorded, transcribed and analyzed with qualitative content analysis.
1 week and 8 weeks after inclusion

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Charite University, Berlin, Germany

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 10, 2022

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 28, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 28, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 30, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 31, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 27, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2024

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • KWT2

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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