Tree Thursday -- Your Brain on Nature: Forest Bathing and Reduced Stress

Studies show shinrin-yoku, also known as forest bathing or time spent in green spaces, can reduce the stress hormone cortisol and increase your immune defense system.

 

By Eva Selhub and Alan Logan
January 8, 2013

 

 

It's no surprise that fresh air is good for your health, but that doesn't always make it easier to get a balance of healthy immersion in nature. Your Brain on Nature (Wiley, 2012) makes a case for better, healthier, greener thinking and improved mental health through exposure to greenspaces and provides tips for how to apply the science of optimial brain health to everyday life. In this excerpt, authors Eva Selhub and Alan Logan discuss research linking shinrin-yoku (Japanese "forest bathing" or "forest therapy") to increased cerebral blood flow, immune defense and improved mental health. 

 

Shinrin-Yoku—Forest Bathing

It is not so much for its beauty that the forest makes a claim upon men’s hearts, as for that subtle something, that quality of air, that emanation from old trees, that so wonderfully changes and renews a weary spirit. —Robert Louis Stevenson 

 

Among the many reasons to preserve what is left of our ancient forests, the mental aspects stand tall. The notion that forests have a special place in the realm of public health, including an ability to refresh the weary, is not a new one. Medical doctors, including Franklin B. Hough, reported in early U.S. medical journals that forests have a “cheerful and tranquilizing influence which they exert upon the mind, more especially when worn down by mental labor.” Individuals report that forests are the perfect landscape to cultivate what are called transcendent experiences—these are unforgettable moments of extreme happiness, of attunement to that outside the self, and moments that are ultimately perceived as very important to the individual.

 

From: http://www.alive.com/articles/view/23253/forest_bathing

In 1982, the Forest Agency of the Japanese government premiered its shinrin-yoku plan. In Japanese shinrin means forest, and yoku, although it has several meanings, refers here to a “bathing, showering or basking in.” More broadly, it is defined as “taking in, in all of our senses, the forest atmosphere.” The program was established to encourage the populace to get out into nature, to literally bathe the mind and body in greenspace, and take advantage of public owned forest networks as a means of promoting health. Some 64 percent of Japan is occupied by forest, so there is ample opportunity to escape the megacities that dot its landscape.

 

Undoubtedly, the Japanese have had a centuries-old appreciation of the therapeutic value of nature—including its old-growth forests; however, the term shinrin-yoku is far from ancient. It began really as a marketing term, coined by Mr. Tomohide Akiyama in 1982 during his brief stint as director of the Japanese Forestry Agency. The initial shinrin-yoku plan of 30 years ago was based solely on the ingrained perception that spending time in nature, particularly on lush Japanese forest trails, would do the mind and body good. That changed in 1990 when Dr. Yoshifumi Miyazaki of Chiba University was trailed by film crew from the Japanese Broadcasting Corporation (NHK) as he conducted a small study in the beautiful forests of Yakushima. It was a test of shinrin-yoku, and NHK wanted to be there. Yakushima was chosen because it is home to Japan’s most heralded forests. The area contains some of Japan’s most pristine forests, including those of select cedar trees that are over 1,000 years old. Miyazaki reported that a level of physical activity (40 minutes of walking) in the cedar forest equivalent to that done indoors in a laboratory was associated with improved mood and feelings of vigor. This in itself is hardly a revelation, but he backed up the subjective reports by the findings of lower levels of the stress hormone cortisol in subjects after forest walks compared with those who took laboratory walks. It was the first hint that a walk in a forest might not be the same as a walk in a different environmental setting.

Since then, university and government researchers have collaborated on detailed investigations, including projects to evaluate physiological markers while subjects spend time in the forest. The research team from Chiba University, Center for Environment, Health and Field Services, has collected psychological and physiological data on some 500 adults who have engaged in shinrin-yoku, and a separate group from Kyoto has published research involving another 500 adults. These studies have confirmed that spending time within a forest setting can reduce psychological stress, depressive symptoms, and hostility, while at the same time improving sleep and increasing both vigor and a feeling of liveliness. These subjective changes match up nicely with objective results reported in nearly a dozen studies involving 24 forests—lower levels of cortisol and lower blood pressure and pulse rate. In addition, studies showed increased heart rate variability, which is a good thing because it means the circulatory system can to respond well to stress and can detect a dominance of the “calming” branch of the nervous system (the parasympathetic nervous system).


Read more: http://www.motherearthnews.com/natural-health/forest-bathing-ze0z1301zgar.aspx#ixzz3HeWVTIDd