Forest Bathing: The Effect Is Real and Large. You Also Cannot Blind Anyone to a Forest.

Forest bathing works, and the effect is larger than most things this site checks. Across 25 studies and 1,876 people, walking slowly in woodland reduced psychological stress with an effect size of 0.71, anxiety 0.77, and depressive symptoms 0.68. [1]

For scale: 0.2 is small, 0.5 is moderate, 0.8 is what researchers call large. These sit in the upper half of that range, which is unusual territory for a wellness practice.

Now the problem, and it does not go away. You cannot blind anyone to a forest.

Why the blinding problem is not a technicality

In a drug trial, nobody knows who got the pill. That is what stops expectation doing the work.

Here, everyone knows. You were driven to a wood, walked among trees for two hours, and then handed a questionnaire asking how stressed you feel. You are aware you have just done the nice thing, and you are aware somebody is measuring whether the nice thing worked.

The reviewers name it precisely: the limitations are “the reliance on self-report measures and the impossibility of participant blinding”. [1] Not the impracticality — the impossibility. No amount of research funding fixes this one.

So the honest reading of a 0.71 is: people taken to forests report feeling substantially better afterwards. Which is worth knowing. It is just not the same claim as the forest having done it.

Except for one number

A second 2026 review, working from a different set of databases and eleven studies, measured something a questionnaire cannot flatter.

Resting heart rate fell by 4 beats per minute (95% confidence interval 6.9 to 1.1). [2]

A heart rate monitor does not know you are having a lovely time. That makes it the most interesting figure on this page — a physiological change, in the direction you would expect if the calm were real rather than reported.

It is a small effect, from eleven studies, and that review graded its own certainty as very low. But it is not self-reported, and on a page where nearly everything else is, that counts for something.

The two reviews do not agree about how much to trust this

Worth stating plainly rather than blending. The larger review graded the stress evidence moderate and the mood evidence low. [1] The smaller one graded everything very low, citing “risk of bias, inconsistency, and imprecision”. [2]

They searched different databases and included different studies — 25 against 11 — so the disagreement is not mysterious. But it means anyone quoting a single confidence level at you has picked one.

Both found substantial heterogeneity: over 74% in the larger review, between 49% and 87% in the smaller. [1][2] The studies agree on the direction and disagree considerably on the size.

What did make the effect bigger

One finding is more useful than any of the headline numbers. In the larger review’s subgroup analysis, two things predicted stronger effects: longer intervention periods, and clinical populations — people who were actually unwell to begin with. [1]

Which is the pattern this site keeps finding. Things work best in the people furthest from fine, the same way box breathing and most of the stress literature behaves. If you are already coping, expect less.

And sustained programmes beat one-off outings. The reviewers recommend “sustained, multi-session programs” rather than a single afternoon. [1] We are not going to give you a number of hours a week, because neither review provides one and the figure you have seen quoted did not come from these.

The verdict

Supported. Twenty-five studies, nearly 1,900 people, consistent direction across three separate outcomes, effects in the medium-to-large range, moderate GRADE certainty on the main one, and a corroborating physiological measure from a separate review. That is a better evidence base than most of the supplement shelf.

What holds it at Supported rather than higher is the thing nobody can fix: the outcomes are self-reported by people who know exactly what happened to them, and the studies disagree with each other a great deal.

The second review’s own summing up is the fairest sentence written about this practice: forest bathing should be treated as “a potential complementary practice for health promotion, and not as an individual preventive or therapeutic intervention”. [2]

Which, translated: go for the walk. It appears to help, it costs nothing, and nobody is selling you anything. Just do not stop treating a diagnosed condition because a wood made you feel better on a questionnaire.

Related: box breathing · doomscrolling · ikigai · all the habits we have checked · every claim we’ve checked