The Health Benefits of 'Taking in a Forest Atmosphere'

Forests are environments of wonderful serenity, immense beauty, and fresh clean air. Personally, I feel wonderful when I take a walk through a forest. I feel more at ease, think more clearly, and leave in a better mood. Many of you have probably had the same experience. And a growing body of scientific evidence confirms that visiting a forest does have quantifiable effects, both physiological and psychological.

In the 1980s, Japan developed a practice called ‘forest bathing’ (‘Shinrin-yoku’), which has become a basic part of their preventative health care. It involves spending time under a forest canopy, walking slowly, and opening up all five of the senses to the surroundings. Essentially, ‘taking in the forest atmosphere’. According to Dr. Qing Li, an associate professor at the Nippon Medical School who studies the effects of forest environments on human health, ‘forest bathing’ can be done anywhere in the world. In fact, the practice is spreading to other countries, including the United States. But even simple, brief interactions around trees or in other green spaces are beneficial to your health.

One way in which spending time in a forest environment has been shown to be beneficial is in reducing stress. As we are all aware, the stresses of life can be daunting, and affect us physically, mentally and emotionally. As mammals, we have a stress-response system which enables us to respond to short-term stressors and threats. That's the positive side of the system. The negative side is that chronic stress is the root cause of many illnesses, including anxiety, high blood pressure, depression, heart disease, and many more. That's because, when the body’s stress-response system is triggered, stress hormones such as cortisol are released throughout the body. In a 2010 study published in Environmental Health and Preventive Medicine, scientists showed that participants exposed to forest environments exhibited lower cortisol levels compared to those in urban environments, indicating that their body’s stress-response system was being triggered less.

Forest environments can also boost the immune system. One of the most important components of our immune system is a group of white blood cells called natural killer cells, which play a crucial role in fighting tumors and virus-infected cells. Dr. Qing Li and his colleagues showed that a walk in the forest increased both the number and activity of natural killer cells in participants. They attributed the effect to phytoncides, organic compounds emitted by trees and plants.

A third benefit of 'taking in a forest environment' is a decrease in blood pressure. In another study conducted in 2011, Dr. Li and his colleagues found that walking in a forest park, compared to walking in an urban environment, lowered both systolic and diastolic blood pressure in middle-aged participants. In the same study, the researchers presented evidence that forest environments may be reducing blood pressure by lowering the activity of the sympathetic nervous system while increasing that of the parasympathetic nervous system, both of which play a crucial role in regulating blood pressure.

In addition to the physiological benefits, forest environments can also improve mood and cognitive function. In a 2007 study published in the journal Public Health, participants reported that negative emotions such as depression and hostility decreased significantly as a result of walking in a forest environment, with a concomitant increase in positive emotions. The following year, Dr. Stephen Kaplan and his team at the University of Michigan showed that interactions with nature can produce marked increases in cognitive performance.

As you can see, the connection between forest environments and human health is an increasingly active and fruitful area of scientific research. The work cited here is only the tip of the iceberg. If you already make it a habit of 'taking in the forest atmosphere', keep on. Science has your back. If you don't, I hope I've enticed you to make time to take a walk on the wild side: immerse yourself in the beautiful local parks and forests where you live.

Author's Note: A modified version of this article was originally published in the 2016 summer issue of Times Publishing Newspapers.