What do you do when life gets stressful? As a medical student, there are weeks when I start to feel overwhelmed by all the study material, the tests, and the lack of time for basic necessities like sleeping and eating. When this happens I know what I must do. And so, I leave everyone and everything–yes, even my cell phone–behind and go for a hike in the woods. As my lungs receive what feels like their first truly clean breath of fresh air in weeks, I swear I can feel everything drop: my heart rate, my blood pressure, my worries. Most outdoor enthusiasts will tell you that they adventure outside because it “feels good,” but a growing body of scientific research is proving that the health benefits of being in nature are numerous, and perhaps more significant than we ever realized.
In Japan it’s called shinrin yoku, which translates to “forest bathing,” and is defined as a “short, leisurely walk in the woods.” Japan is so dedicated to forest bathing as a healing modality that it has designated 48 forests as shinrin-accredited spaces for health and healing. In the United States, a new initiative among park preservation organizations and health providers includes training doctors to give “park prescriptions,” a prescription, sometimes along with or sometimes instead of other medication, for more time spent outdoors in green spaces.
Research from Japan and around the world shows that walking in the forest can:
Improve your immune system. Walking in the forest increases natural killer cell activity by 50 percent (natural killer cells are our first line of defense against viruses and tumor formation) and also increases the expression of anti-cancer proteins.
Balance your hormones. Studies show that anticipating a forest trip significantly decreases levels of salivary cortisol, a stress hormone. Cortisol levels remain low for 2 hours after the walk.
Increase cardiovascular health. Pulse rate and diastolic blood pressure are remarkably lower in study participants who walk in the forest, compared with those who walk in the city. Additionally, research suggests that walking in the woods promotes cardiovascular relaxation by facilitating the parasympathetic (relaxation) nervous system and by suppressing the sympathetic (fight-or-flight) nervous system.
Improve mental and emotional health. A subjective study in Japan found that the “feeling of comfort,” “feeling of calm” and “feeling of refreshment” were significantly higher in those whom had been in the woods than those in the city area. Walking and/or staying in the forest has also proved to reduce the risk of psycho-social stress-related diseases, as well as depression and other, including major mood, disorders.
While most studies on forest bathing involve participants strolling through the woods, you do not need to leave your home to experience the health benefits of green spaces. One of the first research studies about the effects of nature on human physiology involved patients who had had their gallbladders removed and were recovering in the hospital. The patients who had hospital rooms with a view of an outside courtyard required less pain medication and recovered, on average, an entire day earlier than the patients who had rooms facing a brick wall. Other more recent studies suggest that looking out a window at a green space can increase muscle mass and decrease blood pressure. So whenever you get a chance, walk through the park on your way home from work. Eat dinner outside. Line your windowsill with green plants. And whenever you can, go to the mountains.
Written by Kaitlyn Pote, NCNM Naturopathic Medicine Program. Edited by Dr. Elise Schroeder
Li, Q; Morimoto, K; Nakadai, A; Inagaki, H; Katsumata, M; Shimizu, T; Hirata, Y; Hirata, K; Suzuki, H (2007). “Forest bathing enhances human natural killer activity and expression of anti-cancer proteins”. International journal of immunopathology and pharmacology 20 (2 Suppl 2): 3–8. PMID 17903349.
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Park, Bum Jin; Yuko Tsunetsugu; Tamami Kasetani; Takahide Kagawa; Yoshifumi Miyazaki (2 May 2010). “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 and Preventive Medicine 15 (1): 18–26.doi:10.1007/s12199-009-0086-9. PMC 2793346. PMID 19568835.