Phytoncides for the Win!

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As a follow-up to the previous post on getting out in nature (and getting physical activity and play while you are out there), we will discover how breathing in tree air can help stimulate activity of natural killer (NK) cells in your immune system.

“Shinrin yoku” or “forest bathing,” is the increasingly well-known Japanese practice of going into the woods and breathing forest air. 

As it turns out, this can boost both the number and the activity of NK cells for up to a month.  (You should be saying, “Wow!” and “How?”)

Glad you asked…

  1. Spending time in a forest reduces stress, which reduces cortisol, which dampens NK cell activity in humans.
  2. Outdoor air contains abundant invisible microorganisms from soil and water that just float around as we are breathing. (A recent sci-fi movie on Netflix called “Prospect” illustrated this with people exploring a planet that had visible particles floating around in the planet’s air.)
  3. Trees produce aromatic volatile compounds called phytoncides, aka “wood essential oils.”

What Should You Do With this Information? 

One hour of breathing air containing phytoncides significantly amplified NK cell activity.

So…get out and play in the woods! But what if you cannot, for whatever reason?

The same effect of boosted NK cell activity was seen when essential oils of cypress, white cedar, eucalyptus, or pine were diffused into hotel rooms.

I get out and walk in the woods whenever I can – even in winter!  And when I cannot, I get my essential oils from Your Body Needs. And I am thankful to have a wife who is an aromatherapist to help me figure out how to apply this stuff to our every day lives.

And please, Do. Not. Wear. A. Mask. If. You. Are. Outside. 

You will potentially inhibit many of the beneficial microorganisms in forest air from getting into you.  And, perhaps most importantly, all respiratory viruses (yes, including covid-19) are rarely transmitted outside.  Wearing a mask outside is like wearing a raincoat on a sunny day.

Phytoncides are part of a tree’s immune system so it makes sense that we’ve adopted these compounds to benefit ours. Get out and breathe them in or stay in and diffuse some wood essential oils. Just breathe them in any way you can. (But preferably, get outside…)

H/T to Why Does Forest Bathing Boost Natural Killer Cell Function? |

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