On the glorious splendor of your majesty, and on your wondrous works, I will meditate.”Psalms 145: 5 ESV
“Go outside and play!” Turns out mom was right! Evidence is building concerning the mind-body health benefits of outdoor environments. In Japan, immersion in natural surroundings–known as Shinrin-yoku, or “forest-bathing”– is considered preventive medicine!! (Hansen, Jones, & Tocchini, 2017). Read on to learn how getting outdoors can heal your body and your mind!
The magic of the outdoors
Outdoor natural environments provide rich stimulation of all the senses. Such environments pull the mind away from regrets of the past or worries of the future and into the present moment. The therapeutic elements of natural settings according to research include:
- Gentle sound stimulation from birds, streams
- Aromatic smells released by plants due to bio-active substances such as phytoncides
- Visual stimulation from a vast array of colors, lighting, and intensities
- Feelings of an uneven, varied path under the feet, cool rocks, and other touch stimuli
- Fresh air and breezes against the skin
- Taste can be stimulated depending on forest products (when appropriately identified/ safe to consume) (Han, Choi, Jeon, Yoon, Woo, & Kim, 2016)
Forest-bathing in Japan is described as the immersion of oneself in nature with a mindful engagement of the senses. In other words, forest-bathing occurs when you purposefully pay attention to the sights, sounds, feelings, and smells while spending time outdoors in nature.
Restoration of a resting, recovery state
Natural settings are believed to provide health benefits by engaging the parasympathetic nervous system, or the “rest and digest” arm of our nervous system (Hansen et al., 2017). Parasympathetic nervous system activity counters the effects of our innate stress response. When engaged, the parasympathetic nervous system has the following effects:
- Reduction in heart rate
- Relaxation of blood vessels/ vasodilation
- Release of digestive enzymes
- Improved gastric and urinary system motility, promoting excretion of wastes
- Promotion of erection/ sexual activity
- Reduction in inflammatory cytokines and proteins including IL-6 and C-reactive protein
- Improvements in immune system activity (such as improved natural killer cell activity) and function (Kenny & Ganta, 2014; Tindle & Tadi, 2020)
Study findings: natural outdoor settings and health impacts
Researchers in Korea studied workers who experienced chronic, widespread pain involving five or more areas of their body. Workers in both groups were matched in terms of age, gender, smoking status, and other characteristics. One group of 33 workers with chronic pain were treated with a “forest therapy” intervention, while another group of 28 workers made no change in their routine (Han et al., 2016).
The intervention group participated in a 2-day retreat in a wooded environment, with music therapy, meditation, walking, and body-exercises. Measures for both groups included heart rate variability, pain ratings, and natural killer cell activity. The forest therapy group enjoyed the following health benefits:
- Significantly improved heart rate variability
- Significantly improved natural killer cell activity
- Significant reductions in pain (Han et al., 2016)
The control group saw no changes in any of these measures.
Natural outdoor environments and health: a systematic research review
One study of a little over 50 individuals is interesting. A systematic review of 64 studies conducted between 2007 and 2017 is far more informative! Researchers analyzed studies to determine the effects of forest-bathing or nature therapy (Hansen et al., 2017).
Improved mental health and measurable reductions in stress levels
Analysis of 625 Japanese males noted that just a brief, 15-minute exposure to a natural environment resulted in a significant increase in heart rate variability (HRV) for 80% of the participants compared to when the same individuals were exposed to urban environments (Kobayashi, Song, Ikei, Kagawa, & Miyazaki, 2015). Another study of 498 Japanese persons reporting high levels of chronic stress found that time spent in the forest led to reductions in:
- Feelings of hostility
- Anxiety (Morita et al., 2007 as cited in Hansen et al., 2017)
Forest-bathing paired with cognitive behavior techniques including relaxation techniques, meditation, self-reflection, and goal setting produced significant reductions in the stress hormone cortisol (Sung, Woo, Kim, Lim, & Chung, 2012 as cited in Hansen et al., 2017). Participants also reported an increase in quality of life.
Other mental health benefits found in the systematic review included:
- Improved sleep time following 2-hour afternoon walks in the forest
- 61% higher depression remission rates versus traditional psychotherapy
- Pain reductions
- Reductions in distress related to chronic diseases
- Improved sense of well-being and emotional health (Hansen et al., 2017).
Interesting enough, simply viewing images of nature versus built environments leads to improvements in cortisol levels, heart rate variability, and sense of calm/ relaxation (Hansen et al., 2017).
Improvements in persons with diseases of the heart, lungs, or diabetes
Spending time outdoors in natural settings has been shown to reduce the activation of the renin-angiotensin system. Reduced activation of this system leads to a reduction in cardiac workload and blood-pressure in persons with hypertension (Mao et al, 2012 as cited in Hansen et al., 2017). In 20 persons diagnosed with stage I-II heart failure, a randomized-controlled trial demonstrated walking 3o-minutes a day in a park setting produced significantly greater reductions in heart rate, blood pressure, and greater improvements in exercise tolerance versus walking in an urban setting (Grazulevicience et al., 2015). Persons living in neighborhoods with higher densities of trees were noted to have lower reports of cardio-metabolic diseases compared to those living in neighborhoods with lower tree densities (Kardan, Gozdyra, Misic, Moola, Palmer, Paus, & Berman as cited in Hansen et al., 2017).
A separate randomized-controlled trial in persons with chronic obstructive pulmonary disease (COPD) found significant reductions in stress hormones and inflammation levels for those who had exposure to a forest setting versus those in an urban setting (Jia et al., 2016). Walking outdoors in a natural forest setting significantly reduced blood sugar levels for 48 persons with diabetes in a longitudinal study measuring impacts of forest-bathing over time (Hansen et al., 2017). The study authors in an earlier publication noted benefits from forest-bathing include physiologic effects resulting from exposure to bioactive plant-emitted volatile compounds along with air rich in negatively charged ions (Ohtsuka, Yabunaka, Takayama, 1998).
Current research limitations
Limitations in the research include small sample sizes, potential cultural limitations as most research was conducted in Asian populations, and potential confounding factors such as exercise, pollution levels, or other factors. However, research trends consistently note activation of the parasympathetic nervous system. Reports of decreases in stress and improvements in sensations of relaxation and calm show consistency as well, regardless of study design.
Get outdoors! Heal that body and mind!
You don’t have to live in a cabin in the deep wilderness to enjoy the benefits of forest-bathing. Consistent with the research, getting outdoors or otherwise exposing yourself to nature in a variety of settings can boost your physical and mental health. Ways you can get these benefits include:
- Walk, exercise, meditate, or just relax at your town’s / city’s local park
- Visit a state or national park near you
- Take up an outdoor activity like kayaking, paddleboarding, fishing, camping, or bear-wrestling (maybe skip the last one)
- Hike the trails found on state game lands
- Surround yourself with living plants as well as pictures/ images featuring natural settings in your home and work space
- Garden, even if its a small one in your backyard
- Move to a small, isolated cabin in the middle of the deep wilderness 😉
While the research continues to evolve, consistent themes and patterns emerge showing the health-benefits resulting from exposure to outdoor natural settings. Improvements in heart rate variability, reductions in blood pressure, improved sense of well-being, improved sleep, reductions in inflammation, reductions in anxiety and depression–these amazing benefits can be realized through increasing your exposure to the outdoors in nature. These benefits are available to those who are otherwise healthy but stressed, along with those suffering from chronic illnesses. Turns out mom was right all along–get outdoors to heal your body and your mind!!!
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Han, J. W., Choi, H., Jeon, Y. H., Yoon, C. H., Woo, J. M., & Kim, W. (2016). The Effects of Forest Therapy on Coping with Chronic Widespread Pain: Physiological and Psychological Differences between Participants in a Forest Therapy Program and a Control Group. International journal of environmental research and public health, 13(3), 255. https://doi.org/10.3390/ijerph13030255
Hansen, M. M., Jones, R., & Tocchini, K. (2017). Shinrin-Yoku (Forest Bathing) and Nature Therapy: A State-of-the-Art Review. International journal of environmental research and public health, 14(8), 851. https://doi.org/10.3390/ijerph14080851
Jia, B. B., Yang, Z. X., Mao, G. X., Lyu, Y. D., Wen, X. L., Xu, W. H., Lyu, X. L., Cao, Y. B., & Wang, G. F. (2016). Health Effect of Forest Bathing Trip on Elderly Patients with Chronic Obstructive Pulmonary Disease. Biomedical and environmental sciences : BES, 29(3), 212–218. https://doi.org/10.3967/bes2016.026
Kobayashi, H., Song, C., Ikei, H., Kagawa, T., & Miyazaki, Y. (2015). Analysis of Individual Variations in Autonomic Responses to Urban and Forest Environments. Evidence-based complementary and alternative medicine : eCAM, 2015, 671094. https://doi.org/10.1155/2015/671094
Kenney, M. J., & Ganta, C. K. (2014). Autonomic nervous system and immune system interactions. Comprehensive Physiology, 4(3), 1177–1200. https://doi.org/10.1002/cphy.c130051
Ohtsuka, Y., Yabunaka, N., Takayama, S. (1998). Shinrin-Yoku (forest-air bathing and walking) effectively decreases blood glucose levels in diabetic patients. International journal of biometeorology, 41 (3), 125-127. doi: 10.1007/s00484005006
Tindle, J., & Tadi, P. (2020). Neuroanatomy, Parasympathetic Nervous System. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK553141/