Being around trees can help lower your stress hormone levels, making you feel calmer.
Claim Language
Language Strength
definitive
Uses definitive language (causes, prevents, cures)
The verb 'lowers' is a definitive term because it implies a direct, certain effect — that tree exposure causes cortisol levels to decrease — without using qualifiers like 'may' or 'associated with'.
Context Details
Domain
psychology
Population
human
Subject
Spending time in the presence of trees
Action
lowers
Target
cortisol levels in humans
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 (2)
Effects of forest bathing (shinrin-yoku) on levels of cortisol as a stress biomarker: a systematic review and meta-analysis
This study found that people who walked in forests had less stress hormone (cortisol) in their bodies than people who stayed in cities. Since forests are full of trees, this means being around trees helps lower stress.
Effect of nature exposure on perceived and physiologic stress: A systematic review.
This study found that being around nature, like trees, makes people less stressed — and one way it shows this is by measuring a stress hormone called cortisol, which went down when people spent time near trees.