Nature hikes could be a useful adjunct treatment for veterans with PTSD Original paper

Veterans with PTSD who took either nature hikes or urban hikes reported that the hikes reduced stress and made them feel more connected with others. PTSD symptoms were reduced in both groups at the end of the trial (12 weeks), but symptoms increased back to baseline at week 24 in the urban hiking group. However, this was a secondary outcome that the study was not designed to answer.

This Study Summary was published on November 2, 2021.


Posttraumatic stress disorder (PTSD) is a common, chronic mental health condition that affects up to approximately one quarter of military veterans and frequently occurs alongside anxiety, depression, and substance misuse.[1][2] Several psychotherapies and medications are available to treat PTSD, but many people do not receive treatment due to barriers (e.g., stigma about receiving mental health care, lack of knowledge about resources, lack of access to care) and dropout rates are high.[3][4] Therefore, identifying a wider range of approaches that are acceptable and effective is critical. Nature contact has been shown to improve subjective well-being and could be a viable option for veterans with PTSD.[5]

The study

In this 12-week randomized trial, 26 veterans with PTSD were assigned to nature hikes or urban hiking in the Pacific Northwest region of the United States. The nature hikes took place in forest habitats, including old-growth forests, saltwater shorelines, waterfalls, and alpine lakes. Urban hikes were held in primarily built environments and avoided substantial greenery or water features; the selected hikes took place mainly on sidewalks and included sports stadiums, urban art, and retail establishments. A total of 6 hikes were scheduled over 12 weeks, and the hike durations increased gradually from 60–90 minutes (2–3 miles) to 2–3 hours (5–6 miles).

Because this was a pilot trial, the primary outcomes of interest were feasibility and acceptability, as measured by recruitment statistics, retention, hike attendance, and safety. The secondary outcome was PTSD symptoms, as measured by the PTSD Checklist for Diagnostic and Statistical Manual 5 (PCL-5). A statistical test was not performed for the secondary outcome because the study was underpowered and not designed to answer this question.

The results

Over the course of the intervention, the participants in the nature and urban groups attended an average of 56% and 58% of scheduled hikes, respectively. The acceptability of both urban and nature hikes was high, and over 70% of participants gave a positive rating for the hike locations, distance, and pace. Multiple perceived benefits were reported, including weight loss, stress reduction, and feeling more connected to others.

For PTSD symptoms, median PCL-5 scores decreased from baseline to week 12 and remained steady at 24 weeks in the nature hiking group (baseline=41, 12 weeks=32, 24 weeks=31). In the urban hiking group, PCL-5 scores decreased from baseline to 12 weeks but increased to near baseline levels at 24 weeks (baseline=48, 12 weeks=43, 24 weeks=47).


This study was an important first step in the development of a rigorous, fully powered study to evaluate the impact of nature hiking on PTSD symptoms. The results are promising but should be considered with caution because this was a pilot trial.

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This Study Summary was published on November 2, 2021.


  1. ^Jessica J Fulton, Patrick S Calhoun, H Ryan Wagner, Amie R Schry, Lauren P Hair, Nicole Feeling, Eric Elbogen, Jean C BeckhamThe prevalence of posttraumatic stress disorder in Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) Veterans: a meta-analysisJ Anxiety Disord.(2015 Apr)
  2. ^Margaret A Gates, Darren W Holowka, Jennifer J Vasterling, Terence M Keane, Brian P Marx, Raymond C RosenPosttraumatic stress disorder in veterans and military personnel: epidemiology, screening, and case recognitionPsychol Serv.(2012 Nov)
  3. ^Charles W Hoge, Carl A Castro, Stephen C Messer, Dennis McGurk, Dave I Cotting, Robert L KoffmanCombat duty in Iraq and Afghanistan, mental health problems, and barriers to careN Engl J Med.(2004 Jul 1)
  4. ^Elizabeth M Goetter, Eric Bui, Rebecca A Ojserkis, Rebecca J Zakarian, Rebecca Weintraub Brendel, Naomi M SimonA Systematic Review of Dropout From Psychotherapy for Posttraumatic Stress Disorder Among Iraq and Afghanistan Combat VeteransJ Trauma Stress.(2015 Oct)
  5. ^Howard Frumkin, Gregory N Bratman, Sara Jo Breslow, Bobby Cochran, Peter H Kahn Jr, Joshua J Lawler, Phillip S Levin, Pooja S Tandon, Usha Varanasi, Kathleen L Wolf, Spencer A WoodNature Contact and Human Health: A Research AgendaEnviron Health Perspect.(2017 Jul 31)