{
  "schema_version": 1,
  "id": "green-route-stress-walk-boundary-2026",
  "canonical_url": "https://brali-lifeos.github.io/evidence/green-route-stress-walk-boundary-2026/",
  "json_url": "https://brali-lifeos.github.io/evidence/green-route-stress-walk-boundary-2026/index.json",
  "decision": "support-existing",
  "decision_label": "Supports existing guidance",
  "reviewed_at": "2026-09-13",
  "reviewed_by": "Brali Evidence Reviewer",
  "source": {
    "title": "Effects of green exercise on mental health: a systematic review and meta-analysis",
    "url": "https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2026.1802759/full",
    "type": "systematic-review-meta-analysis",
    "doi": "10.3389/fpsyg.2026.1802759",
    "citation_text": "Liu X, Sun Z, Wang X, Dong D, Samsudin SB. Front Psychol. 2026;17:1802759.",
    "study_design": "PROSPERO-registered systematic review and random-effects meta-analysis restricted to peer-reviewed randomized controlled trials and crossover RCTs. PubMed, Web of Science, EBSCOhost, PsycINFO and CENTRAL were searched through 7 November 2025. The review included 51 studies, used duplicate screening/data extraction, PEDro study-quality assessment, GRADE certainty assessment and sensitivity analyses.",
    "population": "3,092 healthy adults aged 18-85 across 51 studies. Ten studies included only men, three only women and 38 included both. Most interventions were walking; the review authors state that the findings primarily reflect low-intensity walking in natural environments.",
    "intervention_or_exposure": "Physical activity performed in environments containing natural green elements, compared with non-exercise, indoor exercise or outdoor exercise in built-up environments with minimal greenery. Intervention formats and settings varied; most studies were short-term and follow-up was generally under three months.",
    "outcomes": [
      "Overall wellbeing",
      "Positive and negative affect",
      "Stress, anxiety and depression symptom scores",
      "Calm, vigor, anger, fatigue and confusion"
    ]
  },
  "supported_claim": "For an existing Brali stress-walk protocol, a safe greener route can be offered as a low-friction optional modifier when it is as convenient as an ordinary route. In the reviewed randomized evidence, green exercise improved average wellbeing and affect relative to pooled non-exercise, indoor-exercise and built-up outdoor comparators. Stress-specific pooled effects favored green exercise in all three comparator categories. This supports 'prefer green when equally practical', not a stronger prescription.",
  "unsupported_or_overstated_claims": [
    "A park, forest or specific amount of vegetation is required for a useful reset walk.",
    "Ten minutes, or any other fixed duration, is the evidence-based optimal dose for stress relief.",
    "Green exercise guarantees an immediate reduction in stress for an individual.",
    "The pooled effects prove that greenery itself, rather than movement, context, expectations or their interaction, uniquely caused the benefit.",
    "Green walking reliably treats depression, anxiety disorders, burnout or another mental-health condition.",
    "The review establishes durable long-term mental-health benefits after the intervention ends.",
    "The evidence supports a specific pace, heart-rate target, breathing pattern, mindfulness routine or screen rule.",
    "Subgroup or setting differences should be converted into a ranked route prescription."
  ],
  "limitations": [
    "Several pooled outcomes showed substantial or high heterogeneity, although sensitivity analyses suggested some results were driven by a small number of studies.",
    "Most individual studies were small, and the authors noted incomplete reporting of randomization procedures and limited blinding in some trials.",
    "Most interventions were walking, so generalization to other forms or intensities of exercise is limited.",
    "Most interventions were short-term, with follow-up generally under three months, so long-term durability is uncertain.",
    "Settings, exercise formats and psychological measures varied across studies.",
    "Stress-specific comparisons contained relatively few studies: three versus non-exercise, six versus indoor exercise and two versus built-up exercise.",
    "The meta-analysis does not isolate a unique biological or psychological mechanism for any observed advantage of greener settings."
  ],
  "target_hack_ids": [
    "10-minute-stress-walk"
  ],
  "target_protocol_ids": [
    "brali:10-minute-stress-walk"
  ],
  "risk_flags": [
    "mental-health"
  ],
  "notes": "Editorial action: update the existing reviewed stress-walk page rather than create a second green-walk hack. Preserve the anti-magic-timer framing, make safety and convenience primary, add 'prefer a greener route when it costs essentially nothing' as an optional modifier, and add a simple observation loop comparing ordinary versus greener routes without presenting N-of-1 impressions as causal proof."
}