Forest Bathing Simply Explained

1. What It Is About

Forest bathing is a practice from Japan. In Japanese it is called Shinrin-yoku. It was developed in Japan in the 1980s. During forest bathing one consciously spends time in a forest. One walks slowly, sits or simply looks and listens. There are no fixed exercises. Stays of several hours are typical. Unlike with sport, it is not about exertion. It is about taking in the forest with the senses: the smell of leaves and wood, the light between the trees, the sounds and the air. Tiny substances that plants release float in this air, the so-called phytoncides. They are also measured in studies. How long one should stay and which forest is best is not fixed. The studies include deciduous, coniferous and mixed forests, at different times of the year and day. Some groups also do breathing exercises or meditation. Because it looks different each time, the studies are difficult to compare.

2. What Studies Show

The most researched areas are fatigue, stress and mood. There are also some studies on the heart and circulation as well as on the immune system, that is, the body's defence.

Blood pressure: A review from 2017 summarises 20 studies with a total of 732 people 1. Time in the forest was compared with time in an environment without nature. In the forest groups, both the upper and lower blood pressure values were lower. The authors describe the difference as significant. The duration of the stays varied from study to study.

Psyche: A review from 2022 evaluated six randomised studies 4. Randomised means: The participants were assigned to a group at random. Anxiety, depression and mood were investigated. After the forest programmes, anxiety and depressed mood were lower and mood was better. In an observational study, people were asked how they felt on a forest day and on a comparison day. On the forest day, hostility and depressed mood were lower and vitality was greater. There was no random assignment here.

Fibromyalgia: A randomised study from 2020 followed 169 people with fibromyalgia, a condition with widespread pain 2. The programme ran for 12 weeks and included several components: education about pain, exercise, conversations, mindfulness and activities in nature, including forest bathing. The participants in the programme reported less impairment, less pain, less fatigue and a better psychological condition. Because several components came together, it is not possible to say what proportion forest bathing had in this.

Defence: A 2021 review examined 13 studies on forest programmes and laboratory values of the immune system 3. Measured were defence cells, the natural killer cells, and substances that these cells form. Most studies reported higher values after the forest stay than before. Many of these studies had no comparison group, and the groups were small.

3. What Remains Unclear

Many of the studies are small. Often a comparison group that does something else, for example a walk in the city, is missing. Then it is not possible to separate what the forest causes and what is due to expectation alone. Blinding is hardly possible with a forest stay: one always knows that one is in the forest. Forest type, season and duration vary from study to study, which is why they arrive at different results. Whether the effect persists after the stay is still an open question. The question of whether duration, frequency or forest type is decisive is also open. Some reviews combine general nature contact and forest bathing; then it remains unclear what the forest specifically contributes. Studies on inflammatory values in humans, on metabolism and the gut are still pending.

4. What This Means in Everyday Life

Forest bathing requires no equipment and no special technique: one is in the forest and perceives what is there. The studies that exist measure above all how people feel during and shortly after a forest stay and which values change. This is clearest with stress, tension and mood. Several studies show lower values for blood pressure, but the conditions were different each time. For the body’s defence the results are first indications, no more. Anyone wishing to assess the situation can separate two questions: whether a forest stay relaxes on a given day, and whether it changes something over weeks. The second question is still open. What remains to be clarified is which forest type, which duration and which frequency underpin the observed differences.

All details with study numbers and sources: detailed page on forest bathing (Shinrin-yoku). For children: Forest bathing (Shinrin-yoku) for children.