Want to Prevent Cancer? Take a Walk in the Forest—Studies on “Forest Bathing”

Wednesday Jul 2 | BY |
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Forest Walking

Studies have found that forest bathing can help boost the immune system
and reduce risk of heart disease.

You’re eating right, exercising, and managing stress. But you’re still worried. Maybe someone in your family had cancer, or you have other risk factors. Is there anything else you can do?

Recent scientific studies shows there is—get to a forest and take a walk.

We’ve always known that spending time in nature is good for us, but now we have real evidence that spending time in the forest, specifically, can create measurable changes in our bodies and minds that have a significant effect on our health.

What is Forest Bathing?

The term shinrin-yoki or “forest bathing” was coined by the Japanese Ministry of Agriculture, Forestry, and Fisheries in 1982. It described the process of taking in the atmosphere of the forest to improve mental and physical relaxation. The practice has been popular in Japan for decades, with citizens escaping to one of the many forests to relax and recharge. To them, it’s an experience similar to aromatherapy, as breathing in the unique air of the forest is a key part of the process. According to a 2003 survey, over a quarter of respondents had participated in a forest-bathing trip.

In 2004, Japan established the Association of Therapeutic Effects of Forests. Just three years later, the International Union of Forest Research Organizations (IUFRO) launched a new taskforce on forests and human health in Finland. That same year, the Japanese Society for Hygiene established the Japanese Society of Forest Medicine.

All these associations have made it possible for researchers to conduct scientific tests on the effect of forest bathing on mental and physical health. The results have shown that if you’re not regularly walking in the forest, you should be!

Health Benefits of Forest Bathing

Turns out that taking a walk in the forest does a lot more for you than simply help you relax—thought in our fast-paced world, that’s significant in itself. Here’s more on what this therapy can do for you:

  • Boost the immune system: Laboratory studies discovered that “phytoncides”—like a-pinene and limonene, which are essential oils from the wood of forest trees—increase the activity of killer cells, responsible for keeping cancer cells in check and for otherwise preventing infections and illnesses. Other studies have found that fragrance from these oils helps boost killer cell activity. In 2010, researchers took it a step further, and conducted tests on healthy male subjects aged 37-55 who actually took a walk in the forest and then took a similar walk in the city. Both walks were 2.5 km in length and lasted about two hours. Researchers measured phytoncides in the air, took blood samples and had participants complete a survey after the trip. They also took follow-up blood samples on day 7 and day 30 after the walks. Results showed that not only did the forest walk increase activity of natural killer cells (while the city walk did not), but the effects were still there 30 days later. In a second part of the same study, researchers found similar effects on women who engaged in forest walks. This part of the study also showed a decrease in the percentage of “T cells,” which indicate mental stress.
  • Relieve stress: In the study mentioned above, researchers measured levels of adrenaline in the urine of both the male and female participants. They found that the forest bathing trips significantly decreased the adrenaline levels, suggesting the participants were under lower stress during their time in the forest. Other studies have found similar results, with forest bathing reducing levels of “cortisol,” the stress hormone, and increasing self-reported vigor, as well as decreasing anxiety, depression, and anger. Measurements of white blood cells also showed that the experience was relaxing for the parasympathetic nervous system. An earlier 2007 study found that the stress-relieving effects were even greater for participants who were experiencing “chronic stress,” suggesting that forest bathing could be part of a therapeutic treatment.
  • Reduce blood pressure and heart rate: In another 2010 study, researchers conducted experiments in 24 areas in Japan. They found that not only did forest bathing reduce cortisol levels, but also reduced average blood pressure levels. Other measurements showed that the experience greatly increased relaxation and decreased stress.
  • Reduce fatigue & improve mood: Information from these studies also shows that even just viewing the forest (without walking through it) helped reduce fatigue and improve mood, when compared to viewing city landscapes. Walking through the forest increased the benefits—results showed that after walking participants scored lower in tension, depression, anger, fatigue, and confusion, while scoring higher in vigor, when compared with walking in the city.

Researchers noted “human beings have lived in the natural environment for most of the 5 million years of their existence. Therefore, their physiological functions are most suited to natural settings. This is the reason why the natural environment can enhance relaxation.”

They added that the effect on killer cells is significant, as the phytoncides can kill tumor cells by releasing anti-cancer proteins. In addition to showing increased natural killer cell function, these studies found an increase level of anti-cancer proteins after forest bathing, suggesting that the trips may “have a preventive effect on cancer generation and development.”

The Trees Are Key

All of these studies point to the trees as providing a big portion of the health benefits. Participants breathe in air laden with phytoncides, which are responsible for that lovely scent one encounters when in the forest. Just like essential oils have shown to have antioxidant, anti-inflammatory, and anti-microbial effects, so their aromas also seem to have healthful effects on the human body and mind. We breathe in the chemicals released by these oils as we walk among the trees, taking in their protective benefits.

So important are the trees, in fact, that studies have shown their presence outside of hospital windows improves recovery. A 1984 study, for example, reviewed data from patients who stayed in a suburban Pennsylvania hospital. Some stayed in rooms with windows that looked out on a small stand of deciduous trees, while others stayed in rooms with windows looking out on a brown brick wall. All were served by the same nurses, with rooms being nearly identical in terms of size and furniture.

Results showed that those who had a view of the trees had significantly shorter hospital stays, had fewer postsurgical complaints, used less-potent pain medications, and received fewer negative comments in the nurses’ charts than those who stayed in the rooms with the view of the brick wall.

Even just looking at images of nature can help some. A 2010 study, for example, found that views of nature help relieve stress and pain in healthcare settings.

For Your Next Forest Walk

To try forest bathing for yourself, find the nearest natural area with trees, and follow these tips:

  • Plan your walk in such a way that you don’t get too tired on the trip.
  • Try to stay at least an hour in the forest surroundings.
  • Take along some water or snacks to make the experience more pleasant if you like.
  • You don’t necessarily have to spend the whole time walking—leave your ideas of a “workout” or “exercise routine” behind. Instead, bring along a journal or a good book so you can just sit and absorb the atmosphere along the way.
  • If you are in dire need of stress or health recovery, plan a two-to-three day trip to a forested area. You may want to stay in a cabin or something similar and walk among the trees every day.
  • For everyday maintenance, a daily walk in a park near your home can also be helpful.
  • Do you practice forest bathing? Please share your thoughts.

    * * *

    Bum Jin Park, et al., “The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan,” Environ Health Prev Med, Jan 2010; 15(1):18-26, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2793346/?_escaped_fragment_=po=19.4444.

    Qing Li, “Effect of forest bathing trips on human immune function,” Environ Health Prev Med, Jan 2010; 15(1): 9-17, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2793341/.

    Li Q Morimoto K, et al., “A forest bathing trip increases human natural killer activity and expression of anti-cancer proteins in female subjects,” Journal of Biological Regulators and Homeostatic Agents, 2008; 22(1):44-55, http://europepmc.org/abstract/MED/18394317.

    Morita E, et al., “Psychological effects of forest environments on healthy adults: Shinrin-yoku (forest-air bathing, walking) as a possible method of stress reduction,” Public Health, 2007 Jan; 121(1):54-63, http://www.ncbi.nlm.nih.gov/pubmed/17055544.

    Roger S. Ulrich, “View through a window may influence recovery from surgery,” Science, April 27, 1984; v224, p420(2): http://mdc.mo.gov/sites/default/files/resources/2012/10/ulrich.pdf.

    Deborah Franklin, “How Hospital Gardens Help Patients Heal,” Scientific America, March 1, 2012, http://www.scientificamerican.com/article/nature-that-nurtures/.

    Vincent E, et al., “The effects of nature images on pain in a simulated hospital patient room,” HERD, 2010 Spring;3(3):42-55, http://www.ncbi.nlm.nih.gov/pubmed/21165860.

    Colleen M. Story

    Colleen M. Story

    Colleen M. Story, a northwest-based writer, editor, and ghostwriter, has been creating non-fiction materials for individuals, corporations, and commercial magazines for over 17 years. She specializes in the health and wellness field, where she writes and ghostwrites books, e-books, blogs, magazine articles, and more.

    Colleen is the founder of Writing and Wellness. Her fantasy novel, “Rise of the Sidenah,” was released with Jupiter Gardens Press in September 2015. Her literary novel, “Loreena’s Gift,” is forthcoming in spring 2016 from Dzanc Books. She lives in Idaho. www.colleenmstory.com


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    1. Gary Collier says:

      When I studied with a naturpath (Mildren Jackson), she told us that, if you have a cold or other ailment, go sit with your back up against a pine tree for about an hour once or twice a day. She claimed that pine and eucalyptus trees were very healing and had a general tonic effect on the whole body.

      Also, the wind blowing through the trees creates negative ions in the air….very uplifting….

    2. Carmen says:

      Yep! Who needs negative ions from the beach when we can get grounded in the forest! Been here a month with 3 more to go. Enjoying my morning walks and evening solar showers. A win-win on forest bathing 🙂

    3. Mari says:

      Oh yes, my favorite pastime is walking in the woods, ever since I was a little girl & would always take in deep breaths for the awesome smells!! Take it a step further & combine ocean or lake & forests! Think I’ll go take a walk in the mangroves this afternoon by the ocean!!

    4. Zyxomma says:

      As a lifelong hiker, I can’t think of much in this world that I prefer to “forest bathing.” I’m overdue for a trip to the woods. A friend got back from vacation this week, and I do believe I’ll ask him to drive me somewhere nearby for a woodland adventure. I’m an aromatherapist, and have always loved the “natural aromatherapy” of a walk in the woods. Of course, oxygen levels are high in the woods, and sleeping under the stars is a real treat. Health and peace.

    5. Liv says:

      This is a really interesting concept and thank you for posting the article. I am sure that many of us have experienced the benefits of this without any conscious realisation. I live in the beautiful French Pyrenees (Hautes-Pyrenees) and either run or walk daily near my home in the forests or in the mountains. Without this practice I definitely feel more stress (I know, how can it be stressful living where you live?! – life is life……). Before I moved here I would come on holiday here 2 – 3 times a year for weeks just hiking, going up high, running when children permitted, etc. and would actually feel very “low” on leaving. The trees, whether in the forest (in May/June one can bathe in the acacia trees’ scent and glow just up the hill from here) or in the mountains (patches of thick beech woods leading upwards to thinner areas of pine with that thick oily scent in full summer), provide stimulation to all of our senses, and the accompanying wildlife creates a complement so full if one actually spends the time as part of it, not merely going through it.

    6. Courtney says:

      Dear Colleen,

      You are write beautifully! Thank you for an excellent article and excellent background research. I got a lot out of this article, and I’m sure that others did, too.

    7. Kym says:

      As Colleen mentions, this is a popular activity here in Japan so I’m happy to see this. The Japanese government popularized the idea but the concept is actually based on much older traditions. A Korean friend has said they also have similar ideas. A small point: the Japanese spelling is shinrinyoku or shinrin-yoku. (Just to help people locate this article through Google, or do their own research.)

      JFYI, Dr. Alan Logan has also researched the idea and has a book on the subject: Your Brain on Nature. I haven’t read the book but have self-experimented (nutritional medicine student here) with some of the ideas he has talked about in interviews. I’ve found them, and also the idea of grounding, e.g., sitting with your feet in a stream, to be really effective.

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