Is Forest Therapy For Real?

I’m wondering if the forest therapy that originated in Japan is available in the U.S. Or is it something we’re just supposed to do on our own by spending time in the woods to reduce stress?

– August 23, 2017

Forest therapy, also called forest bathing, involves spending time in the woods as an antidote to the sometimes-jarring sounds, sights, and smells of city life. Of course, you can get that kind of respite on your own, but a more organized version of forest therapy has now been introduced in the U.S. The Association of Nature and Forest Therapy Guides and Programs, founded in 2012, is training forest therapy guides and hopes to raise awareness of the benefits among health care professionals. Programs are being established nationwide.

As you note, forest therapy originated in Japan, where researchers have been studying its physiological impacts for many years. It appears that forest therapy does have measurable health benefits; for example, it can lower levels of salivary cortisol, the hormone that rises when we’re under stress. One Japanese study showed that gazing at forest scenery for as little as 20 minutes reduced salivary cortisol levels by 13.4 percent. Forest therapy can also lower blood pressure and heart rate and trigger a dramatic increase in the activity of natural killer (NK) cells produced by the immune system to ward off infection and fight cancer. Japanese researchers have reported that spending three days in the forest increases NK activity by 50 percent, a beneficial effect that can last up to one month. One mechanism of this benefit may be through inhalation of phytoncides, compounds released by trees.

I understand that in the U.S., guided forest therapy walks last two to four hours but cover very little distance – no more than a mile, according to the Association of Nature and Forest Therapy Guides and Programs. You may sit and focus on natural sights and sounds much more than you walk. The idea is to slow down and experience nature in a deeper way than you have before.

I’ve written on this site and in my book, Spontaneous Happiness, about the importance of connecting with nature. We are creatures of nature and cannot enjoy optimum physical or emotional well being if we have too little contact with it. Biologist E.O. Wilson coined the term biophilia, which means “love of life or living systems,” to describe this innate human need. I believe it to be as real as our needs for love, food, sex, and community.

Your health will benefit from letting nature into your awareness as often as you can, any way you can. Watch the ever-changing shapes of clouds, admire trees, listen to the wind, look at the moon, at birds, at mountains. And when you do, remember that you are part of nature, connected through it to something larger than yourself.

Andrew Weil, M.D.



Qing Li et al, “Effect of phytoncides from trees on human natural killer cell function.” International Journal of Immunopathological Pharmacology, October-December 2009.

Gregory M. Bratman, et al, “Nature experience reduces rumination and subgenual prefrontal cortex activation.” Proceedings of the National Academy of Sciences, doi: 10.1073/pnas.1510459112

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