Forest bathing is shinrin-yoku, the Japanese practice of a slow, attentive walk among trees, and it costs nothing. A visit reliably calms the nervous system and eases blood pressure a few points on the spot, drawn mostly from short Japanese studies by a few research groups, so those effects read as immediate and have barely been tested past the day of the walk. The famous immune claim, that tree oils lift your natural killer cells, is early and thin, resting on a handful of twelve-person studies from one lab.
Most of what the research measures is the walk itself and time in nature, which shinrin-yoku turns into a ritual of unhurried attention. Go for the walk and the calm it brings, make it a weekly habit, and check yourself for ticks the same day.
Findings & Outcomes
What It Is
Shinrin-yoku means taking in the forest atmosphere: a slow, unhurried walk among trees with your attention open to what you can see, hear, and smell. It was named in Japan in the 1980s as a public-health idea and has built a small trial literature of its own, mostly short studies from a few research groups. It is free, and the walk at its center is one of the best-evidenced things a person can do. It sits inside the much larger evidence on time in nature, which is where the general picture lives.
Anatomy of the Practice
1The first minutes
You slow down and put the phone away. Within minutes the pulse eases, the breath lengthens, and the nervous system tips toward rest. In field studies comparing forests with matched city streets, pulse and blood pressure sat lower among the trees.
2Over a visit
An hour or two of slow walking carries movement, daylight, and quiet together. Blood pressure eases a few points, mood lifts, and cortisol reads lower, though it often read lower before the walk began, a clue to how much of this is the setting and how much is a day off.
3Between visits
The clear effects are the immediate ones. Whether the lower blood pressure or the immune changes carry into the next week has barely been measured, so forest bathing reads best as something that helps in the moment and is worth repeating, not a dose that builds up over time.
What It Does
The findings sort into three groups by how far you can trust them.
The reliable effects are immediate. A slow walk among trees calms the nervous system and eases blood pressure while you are there, and it lowers anxiety in the short term. These are the sturdiest results because they pool the most trials, and each describes the body settling during a single visit.
The open questions come next. Two stay unresolved: whether the lower blood pressure lasts between visits, which has barely been measured, and whether the shinrin-yoku ritual beats an equally pleasant walk in an ordinary park, which the studies almost never test head to head. So how much the ritual adds beyond simply being outdoors among trees is unsettled.
The immune claim sits lowest. A short forest trip has been reported to raise the activity of natural killer cells, an immune cell type, with airborne tree oils proposed as the reason. It is a striking result and a thin one, from a handful of twelve-person studies in a single lab.
The benefit comes from the walk and from time in nature; the shinrin-yoku ritual is the unhurried way of doing it.
The Research & Studies
Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.
Heart And Vascular
Blood pressure runs about 3 mmHg lower in a forest than in a built-up place
Pooling twenty short trials, blood pressure ran a few points lower in a forest than in a built-up place, about 3 mmHg on the top number and under 2 on the bottom. These are readings taken around the visit, not blood pressure managed over time.
Twenty trials with 732 participants contributed the systolic result and 17 trials with 705 the diastolic. Systolic blood pressure was lower in the forest setting (MD -3.15 mmHg, 95% CI -4.12 to -2.18) and diastolic was lower too (MD -1.75 mmHg, 95% CI -2.38 to -1.13). The readings are taken around a single visit rather than tracked over weeks, the trials are small and short, and nobody can be blinded to whether they are standing in a forest or a street. The included studies lean heavily on young Japanese men.
Who this may not transfer to:The pooled trials do not report a combined sex breakdown, and single-sex male samples are common across this literature.
A slow walk in the woods nudges blood pressure down a few points on the spot, which is a fair reason to make it a habit; it sits alongside treatment for high blood pressure rather than replacing it.
The study · 1
Ideno et al., blood pressure-lowering effect of shinrin-yoku (forest bathing), a systematic review and meta-analysis · BMC Complement Altern Med 2017;17(1):409
No clear sign the blood-pressure drop lasts between visits
Forest visits reliably drop blood pressure in the moment, but the reviews find no clear sign the lower reading carries over between visits or manages blood pressure over the long run. Almost no study looked past the day of the visit.
A review of forest bathing in pre-hypertensive and hypertensive adults found consistent blood-pressure reductions measured during and right after a visit, but no clear evidence that the lower pressure persists between visits or that the practice changes blood pressure managed over the longer term. The studies almost all measure the acute drop and stop there, so the absence of a lasting effect reflects how little the durability has been measured as much as anything about the practice, and none was designed to test forest bathing as blood-pressure treatment.
Who this may not transfer to:The reviewed studies report no pooled sex breakdown.
Enjoy the in-the-moment drop and make the walk regular so the moments recur; do not treat a forest visit as a substitute for the things that manage high blood pressure over time.
The study · 1
Yau and Loke, effects of forest bathing on pre-hypertensive and hypertensive adults, a review of the literature · Environ Health Prev Med 2020;25(1):23
How it works
Across 24 forests, the pulse slows and the nervous system tips toward rest
Across 24 forests, young adults came out with a slower pulse, lower blood pressure and a nervous system tipped toward rest rather than alert while in the forest compared with the city. It is the body settling in the moment, measured on single short visits.
Field experiments across 24 forests in 280 participants aged about 22 compared a forest against a city setting. In the forest, pulse rate and blood pressure were lower, salivary cortisol was lower, parasympathetic nerve activity was higher and sympathetic activity was lower. Each person did one forest and one city visit in a set order rather than a randomized one, the exposures were single and brief, and the shifts describe the body relaxing in the moment rather than a lasting change.
Who this may not transfer to:This foundational forest physiology work is drawn from young adults and the field is heavily weighted toward young men.
The study · 1
Park et al., the physiological effects of shinrin-yoku, evidence from field experiments in 24 forests across Japan · Environ Health Prev Med 2010;15(1):18-26
Cortisol reads lower after a forest visit, but it was already lower before anyone entered
Salivary cortisol, a stress marker, ran lower in forest groups than city groups after a visit, but it was already lower before anyone entered the forest, by a wider margin. Groups that differ at the start cannot tell you much about the trees.
Eight studies pooled out of 22 reviewed. Salivary cortisol was lower in forest groups than urban groups after the visit (MD -0.05 ug/dl, 95% CI -0.06 to -0.04), and also lower before the visit began (MD -0.08 ug/dl, 95% CI -0.11 to -0.05), a larger gap. The groups already differed before anyone entered a forest, the review's own authors attribute part of the effect to anticipation, and heterogeneity after the visit was 88%.
Who this may not transfer to:The pooled studies do not report a combined sex breakdown, and single-sex male samples are common in this literature.
Take the stress-hormone forest numbers lightly; the design cannot separate the forest from who chose to be there and what they expected of it, so let the calmer feeling be the reason rather than the hormone.
The study · 1
Antonelli, Barbieri and Donelli, effects of forest bathing (shinrin-yoku) on levels of cortisol as a stress biomarker · Int J Biometeorol 2019;63(8):1117-1134
Diffusing tree phytoncides into a room raised the same immune cells, in a small study
The proposed reason forests might change immune markers is phytoncides, the oils trees give off, and the same group reports that piping these compounds into a room raised the same immune cells. The step from a compound in the air to a health effect a person would feel has not been shown.
Forest air carries volatile oils from trees, mainly alpha-pinene, beta-pinene and other terpenes. The same research group reports that diffusing these compounds into a hotel room raised natural killer cell activity in a small human study, mirroring the forest-trip result, and reviews of forest volatiles catalogue effects on immune and stress markers across cell, animal and small human work. The chain from a measurable compound in the air to an outcome a person would notice is not established, the human data are small and largely unreplicated outside the originating group, and much of the mechanism rests on cell and animal work.
Who this may not transfer to:The human exposure data behind this come from small samples, and much of the supporting mechanism is cell and animal work rather than measurements in people.
The studies · 3
Li et al., effect of phytoncide from trees on human natural killer cell function · Int J Immunopathol Pharmacol 2009;22(4):951-959
Li et al., effect of forest bathing trips on human immune function · Environ Health Prev Med 2010;15(1):9-17
Antonelli et al., forest volatile organic compounds and their effects on human health, a state-of-the-art review · Int J Environ Res Public Health 2020;17(18):6506
Mood & stress
Anxiety eased in the short term across 20 studies, the clearest mood signal
Pooling twenty studies, an unhurried forest visit eased anxiety in the short term, more clearly than it eased low mood. The studies are small and short, and positive results were more likely to be published, so the real effect is probably smaller.
Twenty studies, most in Asia and Europe. Forest bathing reduced symptoms in the short term, with the clearest signal on anxiety, and no study followed participants beyond a few weeks. The authors found indications of publication bias across their analyzes, and the included studies are small, short and mostly without an active comparison, so the pooled figures likely sit above the true effect.
Who this may not transfer to:The review does not pool a sex breakdown, and several of the largest included studies used men only.
The study · 1
Kotera, Richardson and Sheffield, effects of shinrin-yoku (forest bathing) and nature therapy on mental health, systematic review and meta-analysis · Int J Ment Health Addict 2022;20:337-361, published online 2020
Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.
The lift in low mood is smaller and less consistent than the one on anxiety
The same research finds a smaller, less reliable effect on low mood than on anxiety, and a second review agrees: forest bathing lifts mood in the short term, but the depression evidence is thin and the studies are brief.
In the pooled mental-health literature the signal on depressive symptoms is weaker and less consistent than the one on anxiety, and a separate systematic review of forest bathing reaches the same read: relaxation and mood effects appear in the short term, but the depression evidence is thin and the studies are brief. Few of these studies enrolled people with diagnosed depression or followed them long enough to matter for it, so this speaks to a short-term lift in low mood rather than a treatment for depression.
Who this may not transfer to:The pooled studies report no combined sex breakdown, and few enrolled people with diagnosed depression.
The studies · 2
Kotera, Richardson and Sheffield, effects of shinrin-yoku (forest bathing) and nature therapy on mental health, systematic review and meta-analysis · Int J Ment Health Addict 2022;20:337-361, published online 2020
Wen et al., medical empirical research on forest bathing (shinrin-yoku), a systematic review · Environ Health Prev Med 2019;24(1):70
Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.
Anxiety And Stress
People leave a forest walk with less tension and anger and more energy
Across many small studies, people came out of a forest walk reporting less tension, anger and fatigue and more energy on a standard mood questionnaire. It is a self-report from people who know they have just walked somewhere lovely, on short single visits.
A state-of-the-art review of shinrin-yoku and nature therapy found that across many small studies, a forest visit consistently lowered scores for tension, anxiety, anger, fatigue and confusion on a standard mood questionnaire and raised the vigor score, alongside physiological signs of relaxation. The questionnaire is filled in by people who know they have just been walking in a beautiful place, the outcome most open to expectation, and the underlying studies are small, brief and rarely compared against an equally pleasant non-forest activity.
Who this may not transfer to:The reviewed studies report no pooled sex breakdown, and single-sex male samples are common in this literature.
The study · 1
Hansen, Jones and Tocchini, shinrin-yoku (forest bathing) and nature therapy, a state-of-the-art review · Int J Environ Res Public Health 2017;14(8):851
Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.
Studies rarely test the ritual against an ordinary park, so its added value is unsettled
Forest bathing calms people in the short term, but the studies almost never test it against an equally nice walk in an ordinary park, so nobody can say how much the ritual adds over simply being outside among trees. The time in nature is doing most of the measured work.
The forest-bathing reviews report short-term calming and mood effects, but they rarely compare the specific shinrin-yoku ritual against an equally pleasant walk in ordinary green space, so how much the ritual adds beyond time spent outdoors among trees is unsettled. Most studies compare a forest against a city or against sitting indoors, not against another green setting, so they cannot isolate the ritual, and the broader time-in-nature evidence is much larger, with the walk and the green setting carrying effects of their own.
Who this may not transfer to:The reviewed studies report no pooled sex breakdown, and few include an active green-space comparison group.
Since the time in nature is doing the work, any green place counts and the formal ritual is optional; do the version you will actually keep up, and treat the slow attentive style as a way to enjoy it rather than a required dose.
The studies · 2
Hansen, Jones and Tocchini, shinrin-yoku (forest bathing) and nature therapy, a state-of-the-art review · Int J Environ Res Public Health 2017;14(8):851
Wen et al., medical empirical research on forest bathing (shinrin-yoku), a systematic review · Environ Health Prev Med 2019;24(1):70
Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.
Immune Function
Natural killer cell activity rose about 50% in twelve men and held over a week
Twelve men on a three-day forest trip showed a roughly 50% rise in natural killer immune cells that lasted over a week, with no rise on a matched city trip, and tree compounds were measurable in forest air. It is twelve people, unblinded, from one research group, and no study has shown the cell change alters anything a person notices.
Twelve healthy Japanese men aged 35 to 56 took a three-day forest trip and, separately, a matched three-day city trip. Natural killer activity rose about 50% after the forest trip and stayed raised more than seven days, did not rise after the city trip, and urinary adrenaline fell after the forest trip only. Alpha-pinene and beta-pinene were measurable in forest air and near-absent in city air. Twelve people, no randomization, no blinding, fixed trip order, and almost the entire body of this work comes from one group at Nippon Medical School; a companion study in 13 nurses found the same rise in women without a city comparison. A three-day trip away from a Tokyo office differs from an ordinary day in many ways besides the trees, and natural killer activity is a laboratory measure.
Who this may not transfer to:A separate study by the same group in 13 Japanese nurses aged 25 to 43 found the same rise in natural killer activity, without a city comparison trip.
This is the most repeated and the thinnest of the forest claims; take a forest trip on its own merits rather than for a laboratory immune number.
The studies · 2
Li et al., visiting a forest, but not a city, increases human natural killer activity and expression of anti-cancer proteins · Int J Immunopathol Pharmacol 2008;21(1):117-127
Li et al., forest bathing enhances human natural killer activity and expression of anti-cancer proteins · Int J Immunopathol Pharmacol 2007;20(2 Suppl 2):3-8
Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.
Anticancer proteins in immune cells rose in the same twelve men, not a separate finding
The same forest trip also raised the share of immune cells carrying the proteins those cells use to kill targets, with no rise on the city trip and a matching result in a nurses study. It is the same twelve-person study as the immune-cell count, and the protein change has not been tied to anything a person notices.
In the same twelve men, the forest trip raised the fraction of immune cells carrying the cytolytic proteins perforin, granulysin and granzymes A and B, the tools natural killer cells use to kill target cells, while the city trip did not, and a companion study in 13 nurses reported the same rise. This is the same small, unblinded, fixed-order study behind the natural killer count, from the same single group, so it is one body of evidence rather than a separate confirmation, and a change in a protein measured in blood cells has not been linked to any outcome a person experiences.
Who this may not transfer to:A companion study in 13 Japanese nurses aged 25 to 43 reported the same rise in cytolytic proteins.
Read this as part of the same single immune finding rather than independent support for it, and do not take a forest trip expecting it to change your cancer risk.
The studies · 2
Li et al., visiting a forest, but not a city, increases human natural killer activity and expression of anti-cancer proteins · Int J Immunopathol Pharmacol 2008;21(1):117-127
Li et al., forest bathing enhances human natural killer activity and expression of anti-cancer proteins · Int J Immunopathol Pharmacol 2007;20(2 Suppl 2):3-8
Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.
How It Works
Several things happen at once on a forest walk, which is what makes the trees hard to credit on their own. The body moves, and walking alone has strong, well-measured effects on blood pressure and mood, covered on the walking page. A natural scene lets the attention rest. The setting is quiet and green, and the pace is slow. A forest visit measured against a city street, or against sitting indoors, is measuring all of that at once.
Where the forest has been set apart from the city, in field work across 24 forests, the body does settle: pulse, blood pressure, and cortisol read lower, and the nervous system shifts toward rest. These are on-the-spot readings taken during single short visits, so they describe the body relaxing in the moment, not a change carried into the next day.
The immune story rests on one mechanism. Trees give off airborne oils called phytoncides, mainly pinenes and other terpenes, and one Japanese group reports that a multi-day forest trip raises natural killer cell activity for over a week while a matched city trip does not. The same group reports a rise when those tree oils are vaporized in a hotel room overnight. The result is thin: small samples of about a dozen people, unblinded, almost all from one lab, and a change in a cell measured in a test tube has not been tied to anything a person would notice.
Ways to Do It
Nothing here is bought or built; the whole practice is free. What changes between the steps is how you do it and how long, from a plain walk in the nearest wood to the slow, attentive style that gives shinrin-yoku its name. Start with whatever green is closest.
Find the nearest wood, large park, or tree-lined path and walk it slowly, with no goal and no pace to keep. A local park counts; you do not need an old-growth forest. This alone gives you most of what the research measures, since the walk and the green setting carry the bulk of the effect.
Leave the phone in your pocket, slow down further, and let your senses lead: the light through the canopy, birdsong, the smell of soil after rain, the feel of bark. This attentive, unhurried style is the practice as it is taught, and it is what turns a walk into forest bathing.
An ordinary walk in the park is exercise with a destination. Forest bathing is slow, aimless, and sensory, with no goal beyond attention to the place. The studies rarely compare the two head to head, so how much the ritual adds over an ordinary walk in the same green place is unsettled.
Most studies used a single visit of a couple of hours, and the calming effects show up on that timescale. A weekly visit of an hour or two is a sensible standing version, and since the benefit comes from time in nature more than from the trees specifically, split it however your week allows.
Go Deeper
- Time in nature: the much larger evidence base on green space, the weekly dose, and where forest bathing sits within it. Start here for the general picture.
- Walking: the part of almost every forest study with the strongest evidence of its own, and the thing to prioritize.
- Breathwork and HRV: the slow, attentive breathing that pairs with a quiet walk, and what a heart-rate reading can and cannot tell you.
- The stress axis: what cortisol is, why a single reading is hard to interpret, and how the body winds down.
The Chinese Medicine View
Chinese medicine reads the forest through the Wood element, which is tied to spring, to growth, and to the Liver. The Liver is said to govern the free and easy flow of Qi through the body. When frustration, pressure, or a life held too tight constrains that flow, the tradition describes a stagnation felt as tension, irritability, and a stuck, sighing restlessness.
Green, growing, open places are the setting in which that constrained Qi is understood to move again, which is why an unhurried walk among trees fits the picture. The frame is Yang Sheng, nourishing life, the tradition of living in step with the natural world; its founding advice for spring is to rise early and walk in the open with the body unhurried and the mind unforced. That is close to a description of forest bathing reached from a completely different account of why.
The tradition also treats the natural world as a place where the Shen, the spirit or mind, settles. A quiet, spacious setting is where a scattered or agitated Shen is understood to come to rest, which lines up with the calm people report and with the measured shift toward the resting side of the nervous system. Qi is not the nervous system, and the Liver is not a stress hormone; these are two descriptive languages laid over the same experience, developed independently, and neither one certifies the other. The Wood-element view is a coherent account of why time among growing things eases a tight, frustrated state, and it holds the same caution the modern evidence does: the benefit is gentle, and it is not a cure.
Cautions For This Practice
Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.
Full-time woodland workers carry about twice the odds of Lyme infection
Pooling 15 studies of 3,932 people, forestry and agricultural workers carried about twice the odds of Lyme-causing Borrelia antibodies as other workers (OR 2.36, 95% CI 1.28 to 4.34), with an overall seroprevalence around 20% in outdoor workers. In wooded and long-grass country across Europe, North America and northern Asia, the ticks that carry Lyme disease and, in some regions, tick-borne encephalitis, live in the habitat a forest walk passes through. This is measured in people who spend working lives in the woods, so it marks the direction of the risk rather than the size for a casual visitor, transmission usually takes many hours of attachment so removing a tick the same day matters, and the more recent studies found a weaker association than older ones.Magnavita et al., Occupational Lyme Disease: A Systematic Review and Meta-Analysis
Sun on longer or higher walks
The hour outdoors that gives you daylight can also burn, and sunburn is the exposure most tied to melanoma risk. Ultraviolet is strongest between roughly 10am and 4pm, and stronger again at altitude, near the equator, and off water or snow. Use shade, cover up, and put sunscreen on what stays bare. A closed canopy shades much of it; forest edges, clearings, and open ridges do not.
Heat and cold on long walks
A long walk in hot, humid weather can bring on heat exhaustion, and the risk runs higher for older adults, young children, and anyone with heart or kidney disease or taking diuretics or beta-blockers. Go early or late, carry water, and rest in shade. In cold, wet, and wind, dress for it, since cold air raises blood pressure and is harder on anyone with a heart condition or Raynaud phenomenon.
Pollen, and uneven ground
Tree and grass pollen can set off hay fever and asthma in season, so a high-pollen day is one to check before a long visit if you are prone to either. Woodland floors are uneven, with roots and loose stone, so anyone unsteady on their feet has reason to watch the footing, which the [balance and falls](/go/integrative/practice/balance-and-falls) page covers.
Going alone somewhere remote
Woodland is easy to get turned around in. If you are walking alone somewhere unfamiliar or remote, tell someone your route and roughly when to expect you back, and carry a charged phone and water.
Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.
Common Questions
Does forest bathing actually do anything, or is it just a nice walk?
Both, and the walk is most of it. A slow walk in the woods reliably calms people and eases blood pressure a few points on the spot, and short-term mood and anxiety improve in the pooled studies. Most of that comes from being outdoors, from the green setting, and from the walk, a large and well-supported body of evidence in its own right. The ritual of slow, sensory attention is pleasant and may add something, but the studies rarely test it against an ordinary walk in the same green place, so how much it adds beyond time in nature is unsettled. It is a fine thing to do on the plainest grounds.
Is the immune-boosting, natural killer cell claim true?
It is early, not settled. One Japanese group reports that a multi-day forest trip raises natural killer cell activity for over a week, and that the tree oils called phytoncides do the same when vaporized in a room. The studies are small, about a dozen people each, unblinded, and almost all from one lab, and no study has shown that the cell change alters anything a person experiences. Take a forest trip for the calm and the walk, and treat the immune finding as promising but unsettled, not a reason to go.
How is it different from just going for a walk in the park?
In pace and attention more than in effort. An ordinary walk usually has a destination and a pace; forest bathing is slow, aimless, and sensory, with the phone away and the senses leading. The setting can be the very same park. Because the walk and the green space carry most of the measured benefit, an ordinary brisk walk among trees is not a lesser thing; it trades the meditative quality for exercise. Do whichever you will keep up.
How long and how often should I go?
Most studies used a single visit of a couple of hours, and the calming effects show up on that timescale. A standing weekly visit of an hour or two is a sensible target, and one longer visit or several shorter ones both work, since the benefit comes from time in nature more than from any exact ritual. You do not need a wilderness or a full day; the nearest wood or large park, visited regularly, is what the research is describing.
Do I need an actual forest, or will a city park do?
A city park will do. The green-space research measures the vegetation close to where people live, and the forest-bathing studies themselves ran in ordinary managed woods and parks, not only in wilderness. A large park, an arboretum, a tree-lined riverside, or a botanical garden all count. Route around heavy traffic where you can, since cleaner air carries part of the benefit, and go slowly enough to notice the place.
Explore Related
Other pages this one connects to, by the evidence they share, the outcomes they touch, and the ground they cover.
All 18 sources on this page independently checked and cross-referenced.
Thomas Dehli, Founder & Editor, Sacred Lotus
Sacred Lotus has published Chinese medicine reference material since 2001. Integrative pages are held to the same standard as the herb and formula library: cite the source, grade the claim at its real strength, and say where the research has not looked. This page is educational and it is not medical advice. Last reviewed and updated August 9, 2026.
Evidence strength
How confidently the research supports a claim. Strength describes the evidence, not our endorsement.