Forest Bathing

A Japanese national programme

Shinrin-yoku, usually translated as forest bathing, is associated with Japan. A review by the researcher Qing Li states that a national health programme for forest bathing began to be introduced in 1982 by the Forest Agency of Japan for the stress management of workers. This date rests on that single secondary source, written by a leading proponent of the field; a primary Forest Agency document was not found, so the date and the programme's original aims should be treated as unconfirmed.

Early research and naming in English

The same author reports that the Japanese Society of Forest Therapy was established in 2004 to conduct evidence-based research on the effects of forest environments on health. He also states that his team's first shinrin-yoku study, carried out in Iiyama, Nagano prefecture in 2005, was where the English terms shinrin-yoku and forest bathing were first named and defined. These are the author's own statements about his work, and the sources reviewed do not confirm who first used the Japanese term.

Spread of research beyond Japan

A 2017 narrative review of 64 studies, selected from 127 papers identified, found that research was concentrated in Japan and China, with smaller numbers of studies from Korea, the United States, Denmark, Sweden, Lithuania and Israel. The authors called for longitudinal research conducted worldwide. The sources reviewed for this draft do not trace earlier cultural or religious precedents for walking in woodland in Japan or elsewhere, so none is claimed here.

Shinrin-yoku and forest bathing

Li explains that shinrin means forest and yoku means bath in Japanese, so the term refers to bathing in the forest atmosphere, or taking in the forest through the senses. A 2017 review defines it as a traditional Japanese practice of immersing oneself in nature by mindfully using all five senses. The word bathing is figurative in this usage: the practice does not involve water.

Related labels

Other labels appear in the sources reviewed. Li uses forest medicine for a research field, and a private training organisation certifies forest therapy guides. A 2019 meta-analysis describes forest bathing as visiting a forest and breathing its air. These descriptions differ in emphasis, from sensory attention to exposure to a forest environment, and the sources reviewed do not establish that the labels are interchangeable or how research and commercial usage relate. Readers should check which form of practice a given study or service describes.

Formats used in research

The 2017 review reports that studies used a range of formats. Examples quoted from included studies include 12 to 15 minutes of self-paced walking in a forest, sitting to watch the landscape for 20 minutes, and two-hour forest walks on a single day or across several days. Most studies compared a forest setting with an urban one, such as a city commercial area. Research protocols are not the same as everyday practice, and the review does not describe what a typical guided session looks like.

Guides and training

Forest bathing can be self-led or guided. The Association of Nature and Forest Therapy describes its own guide certification as six months of remote training in 14 modules, a four-day in-person immersion, and a requirement for a current Wilderness First Aid or Wilderness First Responder certificate. It states that its certified guides work in more than 65 countries. This is one private scheme described on its own undated web page; it is not shown to be mandatory, independently accredited or the only route.

Participant experience

The sources reviewed describe session length and setting but give little first-hand description of what participants experience or how consent and pacing are handled. Reported outcomes in research are mostly measurements taken after a forest visit, not accounts of the experience itself. Anyone considering a guided session can ask the guide about the route, the expected duration, the ground and weather involved, and whether the group can rest or stop.

Stress management and general wellbeing

The Japanese programme described by Li was framed around stress management for workers. Li's review title also refers to health promotion and disease prevention, which reflects the proponent's framing of the field. An umbrella review of 16 systematic reviews concluded, at abstract level, that the best available evidence supports forest bathing as a complementary practice for psychophysical wellbeing.

Uses not established

The same umbrella review states that evidence for forest bathing as a therapeutic practice for organic diseases needs to grow before clear clinical indications can be formulated. Claims that it treats or prevents a specific disease are therefore not established by the sources reviewed. These sources also do not document why people seek forest bathing in everyday life, so this section records proponents' framing and research conclusions only.

Cortisol meta-analysis

A 2019 systematic review screened 971 articles and included 22, with 8 in a meta-analysis of salivary cortisol. Cortisol was lower in forest groups than in urban groups after the intervention (mean difference -0.05 micrograms per decilitre, 95% confidence interval -0.06 to -0.04; heterogeneity I-squared 88%). It was also lower before the intervention (-0.08; I-squared 46%), which suggests the groups were not comparable at baseline.

The authors conclude that forest bathing can influence cortisol in the short term and that placebo effects may play an important role, and they advise further research because data are limited. A change in a biomarker does not by itself show lasting stress reduction or clinical benefit.

Systematic reviews of wider outcomes

A 2019 systematic review included 28 papers published from 2015 to April 2019 and assessed their quality with the Downs and Black checklist. It found randomised trials scored significantly higher than non-randomised studies and listed possible changes in cardiovascular, neuroendocrine, immune, mood, anxiety and depression measures. Its authors call for better methodological quality and lower risk of bias. This reading is abstract-level, and the findings are qualitative, not pooled.

The 2017 narrative review reports small samples, samples that were similar in age and sex, sampling bias and a lack of longitudinal studies. The 2021 umbrella review of 16 systematic reviews, read at abstract level only, advises further investigation. Evidence is mainly short-term physiological measures and self-reported mood, and outcomes in Western populations and over longer follow-up remain less studied.

What the evidence says about harms

None of the research reviews opened for this draft reports on adverse events. The 2017 narrative review contains no discussion of risks, allergies, ticks or contraindications. The absence of reported harms is not evidence that none occur, and no peer-reviewed source on adverse events of forest bathing was located. Allergy, asthma and mobility cautions were not stated by any authoritative source reviewed, so they are not asserted here.

Woodland hazards

The NHS states that ticks live in woods, long grass and sometimes urban parks and gardens, and that bites are not always painful. Its precautions include covering skin, using insect repellent, keeping to clear paths, checking skin afterwards and removing ticks with fine-tipped tweezers. The NHS advises contacting a GP if flu-like symptoms or a round or oval rash develop within three months of a bite or a visit to a tick-prone area. The page does not mention forest bathing and this guidance is for the United Kingdom.

Training, regulation and care boundaries

No statutory regulation of forest therapy guides was found in the sources reviewed, and the UK and Irish legal position was not verified. Training is offered by private bodies, and one requires first-aid certification. A participant may pause, leave or decline any activity at any time. Forest bathing is an educational topic here, not a substitute for assessment or treatment, and persistent or worrying symptoms are a reason to seek care from a qualified health professional.