Forest Bathing
Wednesday, September 26, 2012 at 11:12PM
Croton Arboretum
Bamboo forest, Arashiyama, Kyoto, Japan
We were inspired to investigate Japanese research on forest bathing therapy after getting a call from an Arboretum visitor whose parent’s anxiety and anger markedly decrease after their walks in the Arboretum. 
While “everybody knows” that a walk in the woods decreases stress, American medicine has been slow to actually measure the benefits. Starting in 1982, however, Japanese doctors have prescribed "Shinrin-yoku" (forest bathing) to decrease the risk and impacts of psychosocial stress-related diseases, including the anxiety, depression and anger associated with dementia and Alzheimers. 
Recent experiments studied the effects of forest bathing on immune system function. The most exciting result to emerge from these studies are that walks in the woods increase both the number and activity of natural killer (NK) cells, a component of the immune system that fights cancer. In one experiment, subjects took three two-hour walks over two days and stayed overnight in a hotel in the forest. As a control, blood tests were taken before the trip on a normal workday. The same tests were repeated after the second and third walks, and then weekly for several months. Elevated NK levels persisted for up to 30 days after the experiment. Follow up studies showed a significant increase in NK activity – which persisted for seven days after a day trip to the forest.
While these experiments were small scale, the study director attributes the improvement in immune activity to breathing air containing phytoncides (wood essential oils), which are antimicrobial organic compounds emitted by trees to protect themselves from insects and rot.
While more research proceeds, these early results point to the possibility that regular walks in the woods are part of a healthy lifestyle that helps us stave off cancer and mitigate the ravages of dementia and Alzheimers.
The Arboretum’s directors are committed to replant the enormous number of trees lost and damaged during the storms of 2011, not only to restore the preserve but as an investment in the health of the human community.
Article originally appeared on Croton Arbotetum (
See website for complete article licensing information.