Much of my six years in the Yukon was spent in the forest. Until recently, I didn't quite know how that time was affecting me.
I came across a piece of research last week (which was also featured at the OAND conference that I attended this weekend) examining the physiological effects of "Forest Bathing". This non-scientific term for arbour exposure was coined as a result of a poetic translation of "Shinrin-yoku" from Japanese to English - and, frankly, I think it's a charming description!
The study was conducted a few times; first on men, then on women with consistent results. The female study was conducted on 13 healthy nurses between the ages of 25-43. After giving blood and urine to assess a baseline, the subjects underwent a three-day/two-night trip to the forest (not a bad study to be involved in)! On the first day, the women walked for two hours in the afternoon through the forest. On the second day, the women walked for two hours in the morning and two hours in the afternoon in two separate forests (a blood draw and urine test was taken after day two). On the third day, after giving blood and urine a third time, the women returned to the city (Tokyo).
When the forest bathing blood samples were compared to baseline samples significant changes were found: forest bathing increased NK activity and the number of NK, perforin, granulysin, and granzymes A/B-expressing cells. In addition, there was a decreased concentration of adrenaline and noradrenaline in urine.
What does all this mean exactly? Well, the bottom line is that the urine analysis proved a decrease in overall systemic stress, indicated by a decrease in stress hormone. The increase in serum (blood) immune modulators indicates that the immune system is working more efficiently. The immune modulators listed above are specific to mutated and cancerous cell (tumour) modulation and destruction. So, it happens that when we spend time with the trees, our immune systems function more efficiently specifically inhibiting cellular mutation and cancer growth! The even more awesome observation from this study is that the increased NK activity lasted for more than 7 days after the trip!! It's perfect really: if we can get some tree exposure on our weekends, the benefits will last us the entire work week!
The conclusion of this study postulates that the exposure to phytoncides, detected in forest air (often responsible for the lovely smell of trees - pine, etc), decrease stress. Decreased stress contributes to an upregulated immune function.
Either way, if you don't already cross country ski or snowshoe, this study may be a good reason to embrace a new forested hobby!
