By Christine Coyle | March 30, 2023
The Art of Shinrin-Yoku
Shinrin-yoku, or forest bathing, was developed by the Japanese Forestry Agency in 1982 as a health intervention. It’s a passive mindful practice that involves the use of all senses with the aim of immersing oneself in nature.
“Humans are hardwired to connect with the natural world,”
– E.O. Wilson, American Biologist
Forest bathing is a form of nature therapy that uses exposure to natural stimuli to promote psycho-physiological relaxation and improved immune system function. There are many benefits of nature on our body, emotions, and cognition. It is a sensory experience that involves slowly walking or sitting in a forest environment and taking in your surroundings using all five senses. Within our bodies, forest bathing has shown to have beneficial effects on the cardiovascular, immune, and neuroendocrine systems, as well as providing psychological benefits.
The parasympathetic nervous system is the primary target in forest bathing. This system is responsible for physiological relaxation, while the sympathetic nervous system controls “fight or flight” responses. During times of stress, our sympathetic nervous system is over-reactive and can sometimes get stuck in the “on” position. Forest bathing has shown evidence of decreased sympathetic activity and increased parasympathetic activity, providing a therapeutic effect on the body.
In the cardiovascular system, research studies have measured heart rate variability (HRV), blood pressure, pulse rate, stress markers, and cardiovascular disease factors to determine the effects of forest bathing. Significant improvement has been found for individuals with high blood pressure, hypertension, and cardiovascular diseases by increasing parasympathetic activity.
A weakened immune system is a result of illness, oxidative stress, or inflammation. Using stress biomarkers, natural killer (NK) cells, T-cells, pro-inflammatory cytokines, and lymphocytes, researchers have been able to measure the physiological response to forest bathing within the immune system. Exposure to trees and plants has shown to produce an increase in NK cell, T-cell, and lymphocyte activity, while inflammatory cytokine activity decreased to improve overall immune function. Individuals who experience COPD, chronic heart failure, type-2 diabetes, and those who are immunocompromised may find forest bathing to help with improving symptoms.
There is an olfactory component in forest bathing. Trees and plants release chemicals called phytoncides, which have the greatest effect on the immune and endocrine systems. By inhaling these molecules, the physiological benefits include decreased stress hormone production and increased NK immune cell activity. Certain trees produce a greater amount of phytoncides and include: birch, oak, maple, evergreen, pine, cedar, spruce, and conifer trees.
Within the neuroendocrine system, the HPA and SAM pathways are the most effected by forest bathing. Under stressful conditions, the HPA axis becomes hyperactive and releases large amounts of cortisol while the SAM axis releases adrenaline in order to respond to a perceived threat. Researchers found a decrease in cortisol, adrenaline, and blood glucose levels, as well as an increase in dopamine production after forest bathing. There is also evidence of positive effects from inhaling phytoncides to help regulate these autonomic pathways.
There are many psychological benefits of forest bathing, especially for individuals who experience anxiety, depression, or stress. Both acute and chronic stress can impact your heart, emotional distress, pain, and sleep patterns. There is a correlation between an improved psycho-emotional state and the regulation of the autonomic nervous system, which suggest there is a psycho-physiological benefit from being in a forest environment. Forest bathing has shown to have a positive effect on emotional states such as decreasing depression, anxiety, hostility, and sleep disorders while improving restorativeness in the body and mind. These changes in mood states can be linked to decrease in cortisol levels after completing forest bathing sessions.
Whether you take a walk in the forest or watch a shinrin-yoku video, you can gain the benefits of nature therapy. Virtual reality has made it possible for individuals who may not be able to physically participate in forest bathing to receive the positive effects of this practice. In a 2022 research study, direct comparisons between physical and virtual forest bathing experiences were conducted in order to validate whether a simulated forest environment has similar effects to a physical forest environment. While physical experiences provide benefits from natural sounds, views, odors, and terrain, virtual experiences can also evoke beneficial effects on current affective states, working memory, and subjective stress. The results of this study suggested that both interventions produced positive effects on reported well-being. Virtual forest bathing can be useful for older individuals, as well as for those who don’t have access to forest environments.
This blog was prepared by Caroline McNeil.