Forest Bathing for Health: How Nature Nurtures Wellbeing

By Anthoni Oisin, BScReviewed by Danielle Ellis, B.Sc.

What is forest bathing?
The mental health connection
Physical health benefits
Nature and urban living
The role of ecotherapy
Incorporating forest bathing into daily life
Conclusion 
References
Further reading

Research suggests that spending time in natural settings is beneficial to both mental and physical health. Some findings are based on the active practice of forest bathing, while others relate to non-deliberate time spent in nature.

The connection between nature and health is not a simple one. Engaging with the natural world is a multisensory, multivariate experience. For that reason, it can be difficult to narrow down which exact components of forest bathing support well-being.

What is forest bathing?

Forest bathing, or shinrin-yoku (森林浴), is a meditative practice in woodland settings. It was developed in Japan in the 1980s to protect the body against stress, and it can be prescribed for anxiety and depression.

Akasawa Shizen Kyuyourin is a national park in Nagano where forest bathing reportedly began. Specialist groups and medical professionals have conducted further research, and similar findings were replicated in other natural settings.

In 2007, Dr. Qing Li founded the Japanese Society for Forest Medicine (JSFM). The JSFM is an institute that supports researchers in investigating the effects of forest bathing using empirical, scientific methodologies.

The mental health connection

Increased levels of neurochemicals that are fundamental to mental well-being have been found in forest bathers. A study found that participants who forest bathed had higher levels of serotonin in serum samples taken after the exercise compared to samples taken beforehand.

Serotonin is a monoamine neurotransmitter associated with mood regulation, cardiovascular function, and certain clinical disorders. Major Depressive Disorder, Seasonal Affective Disorder, and Generalised Anxiety Disorder are all associated with lower or fluctuating serotonin levels.

Psychological restoration can also be encouraged through time spent in nature. Auditory stimulation is thought to play a part in this, with natural sounds positively impacting participants' subjective experiences of focus and happiness.

Birdsong heard in greenspaces seems to increase both perceived and actual levels of mental restoration. These findings were replicated across a number of different studies; some conducted using the Perceived Restorativeness Scale, and others using alpha and beta electroencephalogram imaging.

Physical health benefits

Forest bathing can have an excitatory effect on activity in the parasympathetic nervous system, as forest bathers were found to have lower blood pressure and slower heart rates. For that reason, forest bathing may be positively correlated with neurocardiovascular health.

Forest-based exercise can also have anti-inflammatory effects. Gentle exercise alone can trigger the release of myokines in the musculoskeletal system, which may have direct and indirect anti-inflammatory properties. The flora found in the area could also have compounding effects.

Alpha-pinene and beta-pinene are released into the atmosphere by foliage like conifers. Research found pinenes suppress the body's production of interleukin-6 (IL-6) and tumor necrosis factor-a (TNF-a) when applied topically in an ethanol solution. However, it is not clear if the same findings can be replicated in humans through airborne means.

The production of cytokines causes inflammation in the joints: a sequence of bonded amino acids produced by immune cells. IL-6 and TNF-a are both instrumental in triggering joint stiffness, so reducing their production might have anti-inflammatory potential.

Spending time in nature can also offer other immune benefits. Research was conducted into the immunological potential of forest bathing in the Mecsek mountains in both January and May. In both designs of the study, participants had elevated levels of natural killer T-cells (NKT) in their blood serum after forest bathing.

The exact effect forest bathing had on NKT cells varied depending on two factors: firstly, the type and presentation of the NKT cell, and secondly, the month the study took place. Both months had a statistically significant difference when compared to the pretest regarding TIM-3 expressions on all NKT and NKT^dim cells. However, the effect in January was substantially less than the effect in May.

Nature and urban living

Accessing green spaces in urban settings can be difficult, blocking a large part of the population from accessing nature's benefits. Psychologists, medical doctors, architects, and more are undertaking cross-disciplinary research to combat this access gap.

Urban greenspaces are a vital tool for tackling this issue. Some city-based greenspaces are designed in a way informed by this research. These spaces optimize the comparatively small spaces for maximum restorative potential.

Virtual or synthetic environments may offer alternative forest bathing opportunities to those who cannot access local greenspaces. For example, auditory aspects of forest bathing could be listened to as a soundscape with similar benefits to experiencing it in vivo.

A study published by The Royal Society explored the effect of pre-recorded 'phantom birdsong' on perceived mental restoration. Varying levels of biodiversity were included in each soundscape. The soundscapes appeared to have as much of an effect as 'live' birdsong on mental restoration. Furthermore, the higher the biodiversity, the greater the recordings' effects.

Participants experienced greater benefits from a simulated forest bathing experience when they could connect stimuli with personal experience. This means that virtual forest bathing may be more effective for those who have directly experienced nature, so it may not be a viable treatment for those with little experience.

The role of ecotherapy

Forest bathing's effectiveness, along with other findings regarding human-nature interaction, has informed the basis of a number of other similar therapeutic practices. These practices fall under the umbrella of ecotherapy.

Nature is a core part of ecotherapy, with the view that ecosystems offer well-being support to humans. Some eco-therapeutic practices are undertaken consciously and with intent, such as Kneipp therapy, which is based on cold-water exposure. Other perspectives within the field instead utilize the therapeutic potential of incidental interactions with nature.

Studies into the effectiveness of ecotherapy practices tend to demonstrate overall support for the role of nature in well-being. However, they do not tend to offer a direct causal relationship between any specific aspect of nature and health due to the inherently multifaceted experience being in nature offers. For that reason, the research typically has a holistic approach.

Incorporating forest bathing into daily life

Spending time in nature can be incorporated into a weekly or monthly schedule to help nurture well-being. Although much research is based on long, frequent hikes through national parks, there are other ways of benefiting from the field's findings without becoming immersed in the practice.

Some benefits of forest bathing can be found in spending as little as 15 minutes to two hours in nature. Even small or infrequent amounts of time spent exercising in nature should lead to health benefits, making integrating the practice into daily life easier.

Based on published research, virtual forest bathing may also be a viable option for those unable to access physical greenspaces. There are a number of different ways of applying these findings, from listening to soundscapes to using virtual environments.

Conclusion

Forest bathing and other interactions with nature have a clear basis in supporting well-being. This applies to both mental and physical well-being, with benefits to both being established in the literature.

The exact mechanisms in nature that provide health benefits are harder to establish. It is perhaps possible that the positive effects experienced as a result of forest bathing are a product of interactionism, with multiple variables acting together to cause a particular outcome.

References

• Park, B. J. (2010). The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan. Environmental health and preventive medicine, 15(1), 18-26
• Timko Olson, E. R., Hansen, M. M., & Vermeesch, A. (2020). Mindfulness and Shinrin-Yoku: Potential for physiological and psychological interventions during uncertain times. International Journal of Environmental Research and Public Health, 17(24), 9340
• Peterfalvi, A. M. (2021). Forest Bathing Always Makes Sense: Blood Pressure-Lowering and Immune System-Balancing Effects in Late Spring and Winter in Central Europe. International Journal of Environmental Research and Public Health, 18(4), 2067
• Miyazaki, Y. I. (2014). Forest medicine research in Japan. Nihon eiseigaku zasshi. Japanese journal of hygiene, 69(2), 122-135
• Berger, M., Gray, J. A., & Roth, B. L. (2009). The expanded biology of serotonin. Annual review of medicine, 60, 355-366.
• Jenkins, T. A., Nguyen, J. C., Polglaze, K. E., & Bertrand, P. P. (2016). Influence of tryptophan and serotonin on mood and cognition with a possible role of the gut-brain axis. Nutrients, 8(1), 56.
• Bains, N., Abdijadid, S., & Miller, J. L. (2022). Major depressive disorder (nursing). In StatPearls [Internet]. StatPearls Publishing.
• Cowen, P. J., & Browning, M. (2015). What has serotonin to do with depression?. World Psychiatry, 14(2), 158.
• Li, Q., Ochiai, H., Ochiai, T., Takayama, N., Kumeda, S., Miura, T., ... & Imai, M. (2022). Effects of forest bathing (shinrin-yoku) on serotonin in serum, depressive symptoms and subjective sleep quality in middle-aged males. Environmental Health and Preventive Medicine, 27, 44-44.
• Benatti, F. B., & Pedersen, B. K. (2015). Exercise as an anti-inflammatory therapy for rheumatic diseases—myokine regulation. Nature reviews rheumatology, 11(2), 86-97.
• Li, F., Zhang, J., Lin, M., Su, X., Li, C., Wang, H., ... & Kang, J. (2019). Anti-inflammatory terpenes from Schefflera rubriflora CJ Tseng & G. Hoo with their TNF-α and IL-6 inhibitory activities. Phytochemistry, 163, 23-32.
• Cho, K. S., Lim, Y. R., Lee, K., Lee, J., Lee, J. H., & Lee, I. S. (2017). Terpenes from forests and human health. Toxicological research, 33, 97-106.
• Bates, V., Hickman, C., Manchester, H., Prior, J., & Singer, S. (2020). Beyond landscape's visible realm: Recorded sound, nature, and well-being. Health & Place, 61, 102271.
• Ferraro, D. M., Miller, Z. D., Ferguson, L. A., Taff, B. D., Barber, J. R., Newman, P., & Francis, C. D. (2020). The phantom chorus: Birdsong boosts human well-being in protected areas. Proceedings of the Royal Society B, 287(1941), 20201811.
• Buzzell, L. (2020). Ecotherapy. In Encyclopedia of Psychology and Religion (pp. 739-741). Cham: Springer International Publishing.
• Summers, J. K., & Vivian, D. N. (2018). Ecotherapy–A forgotten ecosystem service: A review. Frontiers in psychology, 9, 1389.
• Locher, C., & Pforr, C. (2014). The legacy of Sebastian Kneipp: linking wellness, naturopathic, and allopathic medicine. The Journal of Alternative and Complementary Medicine, 20(7), 521-526.
• Qi, Y., Chen, Q., Lin, F., Liu, Q., Zhang, X., Guo, J., ... & Gao, T. (2022). Comparative study on birdsong and its multisensory combinational effects on physio-psychological restoration. Journal of Environmental Psychology, 83, 101879.
• Zhu, X., Gao, M., Zhao, W., & Ge, T. (2020). Does the presence of birdsongs improve perceived levels of mental restoration from park use? Experiments on parkways of Harbin Sun Island in China. International Journal of Environmental Research and Public Health, 17(7), 2271.

Further Reading

• All Mental Health Content
• World mental health support and the effect of stigma and discrimination
• A Guide to Coping with Change
• Managing and Reducing Stress
• Analyzing the Stigma Surrounding Mental Health