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Touching Grass


I know that you know that going outside is “good” for you - I would love to shine a light on some interesting and maybe surprising reasons why we feel so much better after some time “touching grass” as the kids say.

The formal practice of shinrin-yoku (literal translation: forest bathing) was defined and developed in the 1980s by the Japanese government as a way to combat increased health concerns that the general population engendered by the shift from agricultural work to tech/office environments. The resulting comparative analysis of pre/post-shinrin-yoku sessions revealed a remarkable shift in stress markers, immunity, and overall sense of well-being.


Of course, nature-based practices are ancient - this was just the first time objective research and measurable outcomes were quantified. The fact that Western medicine is just now catching up does not serve to validate the wisdom that has been held for millennia; but what is does mean is that there is now some interesting data to dive into.  

Reducing that Cortisol: let’s go!

The general practice of forest bathing has been shown in multiple papers to reduce levels of salivary cortisol - the primary stress hormone.  Quick review: the stress response is a natural physiological state that helps us navigate demanding situations. A quick burst of cortisol and its partners adrenaline and norepinephrine work together to motivate us to solve problems and ready us for action. However, our modern, fast-paced society presents us with a seemingly never-ending barrage of physical and mental stressors, resulting in a prolonged or chronic state of stress.  Though helpful in small doses, sustained release of cortisol & friends disrupts nearly all bodily processes contributing to psychological, digestive, cardiovascular and musculoskeletal issues.  In fact, chronic stress has become so prevalent that the World Health Organisation declared it to be “the health epidemic of the 21st century”.  Good news?  The positive effects of forest bathing have been shown to last for 3-5 days.  A 2 hour investment for a 5 day return?  Sounds pretty good to me.


Serious Heart Business

This meta-analysis of forest bathing research revealed that forest bathing interventions were effective at reducing blood pressure & heart rate, increasing heart rate variability (HRV) thereby improving the quality of life of pre-hypertensive or hypertensive participants.  Let’s take a moment to chat about HRV as it’s getting a little more press these days but is a little confusing at first glance.  Without getting too nerdy about it (you’re welcome) HRV is a measure of our physiological resilience.  A high HRV means that we are able to recover quickly from that burst of cortisol et al that I mentioned above and is evidence of an increased ability to adapt to many kinds of internal and external changes aka stress. 

The tl:dr? Touching grass is good for your heart.

More Seratonin, please

Did you know that there's a natural antidepressant in soil? It's true. Mycobacterium vaccae has been shown to stimulate serotonin production!  Serotonin helps to regulate our mood, digestion and sleep.  Not only that, but this mighty little bacteria also causes an uptick in the release of an immune cell known as a cytokine.  These helpful friends control the growth and activity of other immune and blood cells. When released, they signal the immune system to do its job.  So go ahead - get dirty, it’s good for you!

More evidence that Forest Bathing helps the immune system!

Going forest bathing does not mean bringing your rubber duckie and bubble bath - there’s no actual immersion in water.  The bathing aspect refers to the beneficial biogenic volatile organic compounds (BVOCs) that are (literally) showering down from trees.  

Also known as phytoncides these chemicals are the trees' first line of defense against invading fungi, viruses, and pests.  It would be accurate to say that the phytoncides act in a similar way as the human immune system. And wouldn’t ya know it… Studies have shown that inhaling these phytoncides stimulates our immune system boosting  NK or natural killer cells: the important white blood cells that attack and destroy infected cells (including cancer). Not bad, not bad. Just good good.

Breathe it in: Petrichor’s secret

Trees aren’t the only ones releasing BVOCs.  Ethnobotanist Gary Nabhan has led some interesting research into the benefits of petrichor, or the fragrance that is emitted by the compounds released by many plant species in the desert around the rainy season.  "The 'orchestra' of fragrances that are inhaled 'in concert' to generate a sensory effect greater than the sum of its parts"; effects which include anti-inflammatory, neuroprotective, and antidepressant benefits amongst other benefits.

Oh Sacred Geometry!

No longer relegated to black light posters in your stoner cousin's man cave, research has now demonstrated that looking at fractals can reduce stress levels by 60%, which supports the theory that these naturally occurring patterns can activate the areas of the brain that are responsible for regulating stress. And it's not just fractals... In his groundbreaking 1984 research, Dr. Robert Ulrich found that “... surgical patients assigned to rooms with windows looking out on a natural scene had shorter postoperative hospital stays, received fewer negative evaluative comments in nurses' notes, and took fewer potent analgesics than (the same number of) patients in similar rooms with windows facing a brick building wall.” 

If that’s not a mic drop moment for nature I’m not sure what is!

While all these studies are certainly interesting in their own right, when we zoom out and take a macro view of the totality of these impacts - the effect is staggering.  Improving these factors (stress management and immune function) influences many secondary conditions in ways that improve overall health. So, it’s not just a bullet-pointed kind of "bio-hacking" where you get to unlock your potential - it’s actually happening, right here, right now. And all we have to do is be in it.

So that does it for a brief but fascinating overview of some of the research on the physiological effects of spending time in nature… did anything pique your interest? Oh, wait. You are still reading? You are so dedicated. 

Let me know if you’d like a more detailed look at any of the above topics or share the benefits you’ve experienced while communing with nature. 

I always love to hear from you, so please write me if you have any questions. 


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