Healthcare practitioners employ an array of modalities in the treatment of physical and mental health disorders. Medication management, therapy, exercise and other lifestyle changes are regularly recommended. Often overlooked is an inexpensive option for the maintenance of good physical and mental health: nature. There is now a significant body of evidence supporting the mental health benefits of outdoor immersion.
“Green therapy” known as ecotherapy, has been shown to alleviate symptoms of depression. In the early 1980’s, the forest agency of Japan encouraged people to walk in the woods for better health. Known as “forest bathing” or shinrin-yoku, the practice was believed to lower stress. Yoshifumi Miyazaki, researcher at Chiba University in Japan, found significantly lower levels of the stress hormone cortisol in people who spent 40 minutes daily walking in the woods compared to those spending 40 minutes walking in a lab.
Similarly, in a 2010 multi-study analysis, conducted by researchers from the University of Essex in the United Kingdom revealed a 71% reduction in depressive symptoms for those who simply took a walk outside, compared to a members of a control group who walked the same amount of time at a shopping center. Of the shopping center walkers, only 45% reported reduced depression while 22% felt more depressed. Nature exposure produced both short-term and long-term positive health outcomes in self-esteem and mood. The greatest improvements in self-esteem were found in people with mental health disorders.
In 2015, Stanford researchers compared psychological effects of two groups of participants; one which walked for 90 minutes in a high traffic urban setting and another which walked in a grassland setting with trees and shrubs. Although little difference was found in physiological conditions, interestingly, decreased neural activity in the subgenual prefrontal cortex was found in those walking in urban areas. This brain region is involved in rumination, during which individuals may focus on negative emotions, and is implicated in the development of depressive symptoms.
In an increasingly urbanized world, these findings suggest access to a natural environment and the preservation of parks, trees and open spaces may be vital to mental health. Currently more than half of the world’s population resides in an urban area. Notably, city dwellers experience a 40% higher risk of mood disorders compared to rural dwellers. They also experience a 20% higher risk of anxiety disorders and twice the rates of schizophrenia.
At the forefront of studying the connection between people and environment is The Natural Capital Project, a joint partnership between Stanford University, The University of Minnesota, the Nature Conservancy and the World Wildlife Fund. Through an interdisciplinary team, the project develops quantifiable methods to understand the nexus between environment and health. Using science-informed decisions, targeted capital investments are then made to maintain the wellbeing of both.
Exactly how nature works to improve a sense of wellbeing is unclear, however the foregoing studies and projects strongly suggest at the very least, time spent in a natural environment improves people’s moods. Danielle Shanahan, Phd, a researcher at the University of Queensland in Australia, reports simply putting a plant in your window elicits a range of benefits. While some may be able to take a daily walk in a natural setting, we can also strive to make our schools, offices, and living spaces healthier by the addition of natural elements inside and out. Our physical and mental health may depend on it.
