Years ago we heard an intriguing story. A frail, elderly gentleman in India, bent over with age, left his village to wander into the woods to die. Several years later he returned, vigorous, upright and tanned from the sun, claiming he had been rejuvenated by communing with the rocks, the trees, and the mountain streams.
This story came out of Asia’s ancient tradition of nature therapy recently revived in Japan under the name of shinrin-yoku, or “forest bathing.”
Forest bathing is immersing yourself in a forest environment. This means leaving your cell phone and daily concerns behind and spending several hours deep in the woods, walking on trails or sitting with no other purpose than to experience your surroundings through all five senses: smelling the woodsy air; feeling the ground beneath your feet or the bark of a tree or the texture of a leaf; tasting a blackberry or wild mint; listening to bird calls and the sound of the wind rustling through the trees; and taking in the varied sights. If you aren’t alone, you and your companion(s) remain silent so that you can remain attentive in your senses.
Although no scientific claims have been made that forest bathing can rejuvenate the frail elderly, Dr. Qing Li, reputed to be the world’s foremost expert in forest medicine, and author of the book Forest Bathing: How Trees Can Help You Find Health & Happiness, has conducted scientific studies on forest bathing since 2004. He and other researchers have shown that forest bathing:
- Increases the numbers and activity of the body’s natural killer cells, an important part of the immune system’s first line of defense against infectious invaders
- Increases levels of anti-cancer proteins inside cells, suggesting a preventive effect on cancers.
- Reduces blood pressure and heart rate
- Reduces stress hormones, such as urinary adrenaline & noradrenaline & salivary cortisol
- Decreases activity of the sympathetic nervous system (which activates our “fight or flight” response); and increases activity of the parasympathetic nervous system, which promotes relaxation, lowered blood pressure and good digestion
- Increases levels of serum adiponectin, an anti-inflammatory hormone with beneficial effects on insulin sensitivity that also helps to manage weight by controlling blood sugar and by breaking down fatty acids.
- Improves blood sugar control in non-insulin-dependent diabetics
- Increases DHEA sulfate, an adrenal hormone that can become depleted by stress
- Reduces anxiety, depression, anger, fatigue, and confusion
- Increases vigor and cognitive ability
These benefits often persist long after returning to regular life.
Although many of the benefits from forest bathing appear to come from stress reduction, some benefits may come from phytoncides. Phytoncides are volatile organic compounds with antimicrobial, antibacterial & antifungal properties. They are released into the air from all plants, which they protect against insects, animals, diseases & decomposition, and are dense in forest air. Laboratory studies have confirmed that they can increase anti-cancer proteins & enhance natural killer cell activity.
For more on forest bathing, see Dr. Li’s book or his article from Time magazine referenced below.