Forest bathing: what the evidence actually shows
Shinrin-yoku has more research behind it than most wellness practices — and one finding in that research quietly complicates the whole story.
General information, not medical advice. Talk to a doctor about any health concern.
Shinrin-yoku translates roughly as “forest bathing”: the practice of going into woodland and doing nothing in particular. No hiking target, no step count. Just being among trees, slowly, with your senses open.
It is easy to file this under pleasant-but-unmeasurable. It has been measured a great deal, and the results are more interesting than either the sceptics or the wellness industry suggest, including one finding that quietly undermines the tidy version of the story.
The evidence is real but modest, and mostly short-term. Meta-analyses find lower cortisol and lower blood pressure in forest settings compared with urban ones. But the same cortisol review found forest groups had lower levels before the walk began, measured on site — implying that anticipation is doing part of the work. That does not make the effect fake. It makes it partly psychological, which is exactly what you would expect.
Where the practice comes from
Shinrin-yoku was coined in Japan in the 1980s, promoted by the country’s forestry authorities as a public-health measure. The research followed the name: the first physiological studies began in 1990 and expanded through the 2000s, which is why the literature is larger than the topic’s reputation implies.
The practice itself is deliberately undemanding: walk slowly or sit, notice what you can see, hear and smell, and do not treat it as exercise. The sensory attention is the intervention.
What the research found
The most-cited synthesis screened 971 articles, including 22 in a systematic review and 8 in a meta-analysis of cortisol. In all but two of the included studies, cortisol was significantly lower after forest exposure compared with controls, or significantly reduced from before to after.1
A separate meta-analysis of blood pressure pooled 20 trials and 732 participants and found both systolic and diastolic pressure significantly lower in forest environments than in non-forest comparisons.2
So the direction is consistent. Forests are associated with lower measured stress markers. That is a consistent finding, though most of the studies come from Japan and use small groups of young adults.
The finding that complicates it
Now the detail that most summaries leave out, and which we think is the most interesting thing in the literature.
In the cortisol meta-analysis, salivary cortisol was significantly lower in the forest groups than the urban groups both after the intervention and before it — that is, measured at the study site before any walking began.1 The authors flagged this directly: anticipated placebo effects can play an important role.1
In meta-analyses, forest environments are associated with lower cortisol and blood pressure in the short term. Part of the cortisol difference appears before the walk begins, which suggests expectation is part of the effect rather than a contaminant of it.
This is not a debunking. Looking forward to something restorative, then doing it, is a legitimate mechanism — it is roughly how holidays work. It does mean you should be sceptical of claims that a specific compound in forest air is doing the work, or that a recording delivers the same benefit as the trip.
What this means for forest sound
An honest question follows: if you cannot get to a forest, does playing one help?
Partly, and it is worth being clear about which part. Forest bathing as studied is multisensory and involves leaving your normal environment: light, air, temperature, smell, the absence of your desk. A recording delivers one channel of that.
What the audio channel does deliver is real. Natural sounds are associated with lower heart rate, blood pressure and breathing rate than quiet, though a meta-analysis found no difference in self-reported stress3 — the evidence we cover in nature sounds. Forest audio can also mask some background noise, though only when it isn't drowned out by louder sounds. And because attention restoration theory holds that natural scenes hold attention effortlessly, a soundscape with gentle unpredictability, of wind and distant birds and moving leaves, gives your attention somewhere undemanding to rest.
What it will not do is replicate a walk among trees. Treat forest audio as a good version of a different thing rather than a substitute. If you want a built version of the idea, The Emerald Vault generates a forest soundscape live in the browser.
How to do it properly
Go slowly and drop the target. The physiological field studies typically used short, unhurried sessions — about 15 minutes of sitting or gentle walking, not covering ground (the immune studies used multi-day trips). Treating it as exercise changes the intervention.
Use your senses deliberately. The practice is sensory attention: sounds first, then smell, then the small movements of light. This is the part a recording can partly reproduce.
Leave the phone. Attention restoration depends on not being pulled back into directed attention.
Do not expect it to treat anything. These are modest, short-term physiological shifts in mostly small studies. Forest bathing is a good thing to do; it is not a treatment for a medical condition, and it should never replace care you have been prescribed.
There is something quietly reassuring in the anticipation finding. It suggests part of the benefit begins when you decide to go — which means the deciding was never the trivial part.
Frequently asked questions
The evidence points that way. A systematic review and meta-analysis found cortisol significantly lower after forest exposure in all but two included studies, and a separate meta-analysis of 20 trials and 732 participants found lower blood pressure in forest environments. The effects are modest and mostly short-term.
Not exactly, but expectation plays a part. The cortisol meta-analysis found forest groups already had lower cortisol before the walk began, suggesting anticipation contributes to the effect. That is a real mechanism rather than a reason to dismiss the practice.
No — recordings deliver one sensory channel of a multisensory experience. But natural sound has its own evidence for lowering physiological stress markers, and forest audio can mask some background noise, so it is worth using on its own terms.
The physiological field studies typically used short, unhurried sessions of about 15 minutes of sitting or gentle walking, though the immune studies used multi-day trips. The consistent element is slow, sensory attention rather than distance covered.
Sources
- Antonelli, M., Barbieri, G. & Donelli, D. (2019). Effects of forest bathing (shinrin-yoku) on levels of cortisol as a stress biomarker: a systematic review and meta-analysis. International Journal of Biometeorology, 63(8), 1117–1134. (971 articles screened, 22 in the systematic review and 8 in the meta-analysis; cortisol significantly lower in forest groups both before and after intervention, which the authors attribute in part to anticipation and placebo effects.) pubmed.ncbi.nlm.nih.gov
- Ideno, Y. et al. (2017). Blood pressure-lowering effect of shinrin-yoku (forest bathing): a systematic review and meta-analysis. BMC Complementary and Alternative Medicine, 17, 409. (20 trials, 732 participants; systolic and diastolic blood pressure significantly lower in forest than non-forest environments.) pmc.ncbi.nlm.nih.gov
- Fan, L. & Baharum, M. R. (2024). The effect of exposure to natural sounds on stress reduction: a systematic review and meta-analysis. Stress, 27(1), 2402519. (Natural sounds lowered heart rate, blood pressure and breathing rate compared with quiet; no difference in perceived stress.) tandfonline.com