Forest air doesn’t just feel fresher and better—inhaling phytoncide seems to actually improve immune system function.
“Don’t effort,” says Gregg Berman, a registered nurse, wilderness expert, and certified forest bathing guide in California. He’s leading a small group on the Big Trees Trail in Oakland one cool October afternoon, barefoot among the redwoods. Based on scientific studies at Nippon Medical School in Tokyo, they measured the activity of human natural killer (NK) cells in the immune system before and after exposure to the woods. These cells provide rapid responses to viral-infected cells and respond to tumor formation, and are associated with immune system health and cancer prevention. In a 2009 study Li’s subjects showed significant increases in NK cell activity in the week after a forest visit, and positive effects lasted a month following each weekend in the woods.
This is due to various essential oils, generally called phytoncide, found in wood, plants, and some fruit and vegetables, which trees emit to protect themselves from germs and insects. Forest air doesn’t just feel fresher and better—inhaling phytoncide seems to actually improve immune system function.
Dr Lynn began to do her Forest bathing after she suffered damage to her nervous system from a pesticide poisoning in 2014. She was in distressing pain. “I found that the world had become very noisy. It felt like a constant clanging to my nerves. Walking without any noise soothed me for many hours. It became a sort of tonic for my soul. The pain would lift and I would catch a glimpse of myself prior to the poisoning.” Nature heals many things.
Stress is the number one killer of adults The tonic of the wilderness was Henry David Thoreau’s classic prescription for civilization and its discontents, offered in the 1854 essay Walden: Or, Life in the Woods. Now there’s scientific evidence supporting eco-therapy. The Japanese practice of forest bathing is proven to lower heart rate and blood pressure, reduce stress hormone production, boost the immune system, and improve overall feelings of wellbeing.