Forest Bathing: How a Quick, Leisurely Visit to the Forest Can Reduce Stress and Boost the Immune System
A Japanese concept that came to life in 1982 is making its way to the United States to treat something that virtually every human experiences: stress. Whether it’s heart disease, immune function, or some other malady, stress always seems to have a hand in making things worse. By being prescribed forest bathing, or forest therapy, individuals might be able to kill multiple birds (chronic diseases) with one stone (forest meditation).
What is forest bathing?
In the United States, the Association of Nature & Forest Therapy is responsible for Certified Forest Therapy guides, who help those interested in the healing influence of the jungle become immersed in the sights and smells of nature. No, it’s not just a thoughtful hike. In fact, forest therapy, also known as “Shinrin-yoku,” is defined by having no specific destination, simply an aimless journey into the atmosphere of the forest.
Researchers are interested in the healthy properties of forest therapy that, in particular, seem to boost immune function, which can improve health on many different levels: preventing cancer, fighting infection, and enhancing heart health. Association of Nature & Forest Therapy founder Amos Clifford wants health care providers to acknowledge the benefits of forest therapy and prescribe it to help their patients reduce stress.
Why does stress negatively impact the human immune system?
The fight or flight response hasn’t always negatively affected human health because of its enhancing influence on stress and the immune system. Early in human history when survival depending on an individual’s ability to flee natural disasters or face predators, the fight or flight response was a matter of life and death. Fast forward to present day, and humans have houses to take cover in and little to no exposure to predators. We still experience the fight or flight response in our daily lives, but it’s almost always not a matter of survival; it’s the things many of us would acknowledge as daily stressors: work, school, and other responsibilities.
Essentially, the body is responding to a stressful day at work the same way it would if you were about to be attacked by a lion. The surge in immune activity may be worth it in the lion situation, but for a non-life threatening situation, the extra activity ends up negatively affecting health over time.
In addition, think about the way some people cope with stress - it’s usually not with healthy habits like getting more sleep or taking a night off of staring at a television or computer screen. Instead, it’s often alcohol, unhealthy sleeping patterns, smoking and other drugs.
What specifically does forest therapy and stress relief do for the human body?
In a 2010 Environmental Health and Preventative Medicine study, scientists conducted a series of field experiments in 24 Japanese forests. Twelve participants spent time walking, once in a city area and once in the forest. Researchers collected data before and after on several stress-related factors. They found that the walks in the forest environments lowered a series of stress-inducing factors, including cortisol (a stress hormone), pulse rate, blood pressure, sympathetic nerve activity (“fight or flight”) and that it enhanced parasympathetic nerve activity (“rest and digest”).
Other studies have suggested that tree compounds in the forest air, called phytoncides, also reduce stress hormone levels and blood pressure. Even more, phytoncides have been shown to enhance activity of immune cells called natural killer cells, which are known to fight cancer, bacteria, and viruses.
How does this benefit immune health?
Sympathetic nerve activity results in the release of substances that revv up the immune response. Increased cortisol levels lead to a failure of immune cells to respond to anti-inflammatory processes. Together, an overactive inflammatory reaction ensues, which can contribute to a plethora of inflammation-related diseases like multiple sclerosis, coronary heart disease, rheumatoid arthritis, asthma, and allergies. Plus, these inflammatory reactions use energy, taking away from other bodily functions.
"Forest bathing could be considered a form of medicine," says Duke University physician Philip Barr, MD. "And the benefits of nature can be accessed so simply."
Sources: NPR, Environmental Health and Preventative Medicine, Psychological Bulletin