Among the many recommendations that seem like good ideas, we’ve often heard that getting out in nature is a healthy practice. But our mission is not to simply recapitulate what may represent common beliefs, but rather to explore these practices in terms of their scientific support.
As it turns out, there is a lot of science happening right now that is looking specifically at the health benefits ascribed to nature exposure. Much of the literature is being generated by researchers in Japan, where nature exposure is referred to as Shinrin-yoku, a term created by the Japanese Ministry of Agriculture, Forestry, and Fisheries in 1982, and defined as making contact with and taking in the atmosphere of the forest, or “forest bathing.”
In a study appearing in The Japanese Society of Hygiene, researchers aimed to scientifically evaluate the notion that there are health benefits associated with nature exposure. They conducted field experiments in 24 forests across Japan involving 12 subjects. The study participants spent the day in either a city or forest environment, and as a cross-check, the following day they were sent to the other area. The subjects underwent evaluation of their pulse rate, heart rate variability, blood pressure, and measurement of their salivary cortisol level. Cortisol is a hormone created in the adrenal gland which increases in response to real or perceived threat. It has been termed a “stress hormone” since it does increase when a person is exposed to a stressful event. Similarly, heart rate variability is a useful tool to assess the stress response. Higher levels of heart rate variability are associated with less sympathetic (stress-related) activity.
All of the measurements were made at the same time of day throughout the study; early morning, before breakfast, and before and after walking and taking in the surrounding environment.
The researchers were able to clearly demonstrate that, compared to a typical city environment, profound health benefits were observed in the subjects when they experienced Shinrin-yoku. Across the board, all of the measured parameters were significantly better when subjects were in naturem including lower blood pressure, pulse rate, salivary cortisol level, and better heart rate variability.
Here’s what the authors had to say about their findings:
These results of Shinrin-yoku studies will contribute to support the development of a research field dedicated to forest medicine, which may be used to develop new strategies in preventive medicine. The results of the field experiments also provide a platform for interested enterprises, universities, and local governments to promote the effective use of forest resources in stress management, health promotion, rehabilitation, and the prevention of disease.
We talk a lot about the fundamental importance of lifestyle choices involving things like exercise, diet, sleep, stress and relationships. It seems clear that the growing body of well-designed scientific studies clearly validate the health supportive effects of nature exposure. In our new book, Brain Wash, we explore Shinrin-yoku in great detail and reveal how simply exposing oneself to nature, even when in a city, can provide significant benefits not only for general health, but for mood and happiness as well.