There aren't many studies on forest bathing and stress hormones, and the ones we have aren't all that reliable—so we can't say for sure yet if walking in the woods lowers cortisol.
Claim Language
Language Strength
probability
Uses probability language (may, likely, can)
The claim uses 'suggest' and 'preliminary and insufficient to draw firm conclusions,' which indicate uncertainty and likelihood rather than certainty, placing it in the probability category.
Context Details
Domain
psychology
Population
human
Subject
The limited number of studies included in the meta-analysis (n=8) and the variability in study quality
Action
suggest
Target
that current evidence on forest bathing and cortisol is preliminary and insufficient to draw firm conclusions
Intervention Details
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Evidence from Studies
Supporting (1)
Effects of forest bathing (shinrin-yoku) on levels of cortisol as a stress biomarker: a systematic review and meta-analysis
This study looked at whether spending time in the forest reduces stress hormones, and found that it does — but only based on 8 small studies, so scientists say we need more research before being sure. That matches the claim perfectly.