I’m sure that you probably intuitively know and feel the benefits of a walk in the woods. For me, there’s something calming and refreshing about being with nature and I usually come away from a walk with some clarity and answers to burning questions. In Japan, the practice of Forest Bathing is considered an important part of life, and scientists there are proving that it lowers heart rate and blood pressure, reduces stress hormone production, boosts the immune system, and improves overall feelings of wellbeing.
Forest bathing, meaning spending time around lots trees, became part of a national public health program in Japan in 1982 when the forestry ministry coined the phrase shinrin-yoku and promoted topiary as therapy. Nature appreciation—picnicking en masse under the cherry blossoms, for example—is a national pastime in Japan, so forest bathing quickly took. Forest bathing works similarly: Just be with trees. No hiking, no counting steps on a Fitbit. You can sit or meander, but the point is to relax rather than accomplish anything. The human nervous system is both of nature and attuned to it, so spending time in nature entrains the autonomic nervous system to the frequencies of nature, leading to a restorative balanced state known as coherence.
The effects of Forest Bathing can last for months
From 2004 to 2012, Japanese officials spent about $4 million dollars studying the physiological and psychological effects of forest bathing, designating 48 therapy trails based on the results. Qing Li, a professor at Nippon Medical School in Tokyo, measured the activity of human natural killer (NK) cells in the immune system before and after exposure to the woods. These cells provide rapid responses to viral-infected cells and respond to tumour formation, and are associated with immune system health and cancer prevention. In a 2009 study Li’s subjects showed significant increases in NK cell activity in the week after a forest visit, and positive effects lasted a month following each weekend in the woods.
"The NHS could save £2.1bn a year if it prescribed woodland walks" Woodland Trust
This is due to various essential oils, generally called phytoncide, found in wood, plants, and some fruit and vegetables, which trees emit to protect themselves from germs and insects. Forest air doesn’t just feel fresher and better—inhaling phytoncide seems to actually improve immune system function.
Forest environments promote lower concentrations of cortisol, lower pulse rate, lower blood pressure, greater parasympathetic nerve activity, and lower sympathetic nerve activity than do city environments. Concluded a 2010 study on the effects of Forest Bathing by Japan’s Chiba University.
Experiments on forest bathing conducted by the Center for Environment, Health and Field Sciences in Japan’s Chiba University measured its physiological effects on 280 subjects in their early 20s. The team measured the subjects’ salivary cortisol (which increases with stress), blood pressure, pulse rate, and heart rate variability during a day in the city and compared those to the same biometrics taken during a day with a 30-minute forest visit. “Forest environments promote lower concentrations of cortisol, lower pulse rate, lower blood pressure, greater parasympathetic nerve activity, and lower sympathetic nerve activity than do city environments,” the study concluded.
In other words, being in nature made subjects, physiologically, less sympathetic (the fight or flight arm of the autonomous nervous system). The parasympathetic nerve system controls the body’s rest-and-digest system while the sympathetic nerve system governs fight-or-flight responses. Subjects were more rested and less inclined to stress after a forest bath.
Forest Environments are therapeutic landscapes
Trees soothe the spirit too. A study on forest bathing’s psychological effects surveyed 498 healthy volunteers, twice in a forest and twice in control environments. The subjects showed significantly reduced hostility and depression scores, coupled with increased liveliness, after exposure to trees. “Accordingly,” the researchers wrote, “forest environments can be viewed as therapeutic landscapes.”
The benefits of Forest Bathing can still be felt in urban areas; parks and local woods provide the same level wellness improvement as wandering in the wilderness.
City dwellers can benefit from the effects of trees with just a visit to the park. Brief exposure to greenery in urban environments can relieve stress levels, and experts have recommended “doses of nature” as part of treatment of attention disorders in children. What all of this evidence suggests is we don’t seem to need a lot of exposure to gain from nature—but regular contact appears to improve our immune system function and our wellbeing.
So the next time you are at a loss with what to do, get out amongst the trees. Brief, regular exposure to nature could have a profound impact on your physical and mental wellbeing.
Livini, Ephrat,The Japanese practice of ‘forest bathing’ is scientificially proven to be good for you. World Economic Forum. 2017.
Li Q1, Morimoto K, Nakadai A, Inagaki H, Katsumata M, Shimizu T, Hirata Y, Hirata K, Suzuki H, Miyazaki Y, Kagawa T, Koyama Y, Ohira T, Takayama N, Krensky AM, Kawada T., Forest bathing enhances human natural killer activity and expression of anti-cancer proteins. International Journal of Immunipathology Pharmacology. 2007.
Park BJ, Tsunetsugu Y, Kasetani T, Kagawa T, Miyazaki Y. 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 Preventative Medecine. 2010.
Morita E, Fukuda S, Nagano J, Hamajima N, Yamamoto H, Iwai Y, Nakashima T, Ohira H, Shirakawa T., Psychological effects of forest environments on healthy adults: Shinrin-yoku (forest-air bathing, walking) as a possible method of stress reduction. Public Health. 2007.
Kuo, F., Taylor,A., A Potential Natural Treatment for Attention-Deficit/Hyperactivity Disorder: Evidence From a National Study. The American Journal of Public Health. 2004.
Gould van Praag, C., Garfinkel, S., Sparasci, O., Mees, A., Philippides, A., Ware, M., Ottaviani, C., Critchley, H., Mind-wandering and alterations to default mode network connectivity when listening to naturalistic versus artificial sounds. 2017. Nature.