Nature’s Medicine

Are there more benefits to trail-running verses road–running?

That is the question.  Whether you’re a veteran of the trail, or you’ve just gotten the first few trail runs under your belt, you can feel the difference in your body and your mind.

Let’s start with the body.  It feels different to run on hilly trails than paved streets with a few exceptions (looking at you, San Fran).  The ever-changing terrain means with each footfall, you engage different muscle groups, continuously switching from hips to quads to hamstrings and calves and back again.   Your nervous system gets feedback via proprioception, knowing where you are in space relative to your surroundings.  At first, you consciously shut down mental chatter so you can focus on where your feet go.  Then, you adjust your breathing to compensate for the increased cardiac load.  And so it goes: mud, rocks, trees, birds, inhale, mushrooms, moss, ice, pinecones, pine needles, exhale.  Reset.  Settle in.  Blend into your surroundings.  Become wild.

What happens on a molecular basis inside of us influences the rest of the workout and has a lasting impact on our immune system and nervous system.


Running the dirt ribbon.


Both physical exercise and time spent in nature have been shown to improve health outcomes, but what happens if you exercise in nature?  In studies comparing exercise in rural areas versus urban areas, there is a synergistic effect that occurs repeatedly when people exercise in nature.  Sure, you get benefits from running, but when you exercise in a natural setting, you strike a virtual goldmine of health benefits.

There is now compelling evidence that spending time in the forest, specifically, can improve our health on several levels.  Why the forest? Most people can feel the immediate effects of running in the forest within minutes of that first squish of mud.  It’s that. It’s the fun, but it’s also the actual trees and plants.  Large trees produce phytoncides, which is part of what you smell when you inhale a lungful of cedar or pine scent.  Other smaller plants, like garlic and onions have phytoncide components, but the big aromatic trees in the forest are particularly potent.  Phytoncides, like alpha and beta pinene (as in pine trees), when inhaled actually increase the function of NK cells in the immune system.  NK stands for “natural killer”, and these cells are activated in the presence of viral infections, bacteria, and even cancerous tumors.  You want them to be consistently responsive.  Running in nature, breathing nature actually gives you an immune boost.  How righteous is that?


Always having fun in the forest.


That’s just the body, what about the mind?  It turns out that spending time in nature actually helps us focus.  I am a trail sister, and while it’s a big part of who I am, there are seemingly endless numbers of things vying for my attention anytime I’m off the trail.  Most days, I’m great at tackling the to-do list, but I know my limits.  When I’m there, I know it’s time to hit the trail, or at least get some fresh air (preferably with some pinene in it)!  My best problem solving often comes while I’m on-trail.  Whether it’s a particularly complicated patient case, or trying to figure out how to get my kids to brush their teeth at the same time without clobbering each other. The focus derived from the simplicity of one foot in front of the other lends itself beautifully to calm, attentive energy.  Just having so many balls in the air: work, school, family, other hobbies (right, we have other hobbies besides running?!)…can mentally drain a sister.

We are known for our abilities, as women, to multitask, but that kind of attention is not sustainable.  Resets are necessary, and the more balls in the air, the more often we need to hit that button.  Trail running actually gets you there pretty efficiently.  Any time in nature, moving, can get you there, because you shift from cognition to being as soon as you feel the letting go.


Trail Sisters 🙂


In elementary school, we used to have lots of PE.  Today’s kids have “brain breaks” where they stretch, dance, jump and do yoga periodically throughout day.  There is less PE, but we still know that we need to move our bodies to keep our brains happy for learning and focus.

So the take home is this:

  • Regular breaks for our bodies and brains are necessary and healthy.
  • Running in urban areas provides measurable reported stress relief and increased sense of well-being.
  • Forest Running provides a massive boost to mental clarity, based on cognitive tests; and immune function, based on blood tests.
  • When we run in the forest, we become physiologically interactive with our immediate surroundings, and the benefits have a direct impact on our well-being.

Is trail running more beneficial to you than road running?  I know what’s true for me, and diving into the molecular origins of “why does it feel SO GOOD, even when it feels tough” has got me wrapping up this article and lacing my shoes to cash in on nature’s medicine.




Li Q1Kobayashi MWakayama YInagaki HKatsumata MHirata YHirata KShimizu TKawada TPark BJOhira TKagawa TMiyazaki Y. Effect of phytoncide from trees on human natural killer cell function. Int J Immunopathol Pharmacol. 2009 Oct-Dec;22(4):951-9.

Li Q1, Kobayashi MInagaki HHirata YLi YJHirata KShimizu TSuzuki HKatsumata MWakayama YKawada TOhira TMatsui NKagawa T. A day trip to a forest park increases human natural killer activity and the expression of anti-cancer proteins in male subjects. J Biol Regul Homeost Agents. 2010 Apr-Jun;24(2):157-65.

Weinstein A.A., Deuster P.A., Francis J.L., Beadling C., Kop W.J. The role of depression in short-term mood and fatigue responses to acute exercise. Int. J. Behave. Med. 2010;17:51–57. doi: 10.1007/s12529-009-9046-4. 

Park B.J., Tsunetsugu Y., Kasetani T., Kagawa T., Miyazaki Y. The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): Evidence from field experiments in 24 forests across Japan. Environ. Health Prev. Med. 2010;15:18–26.

Berman M.G., Jonides J., Kaplan S. The cognitive benefits of interacting with nature. Psychol. Sci. 2008;19:1207–1212

Rogerson M., Brown D.K., Sandercock G., Wooller J.-J., Barton J. A comparison of four typical green exercise environments and predictions of psychological health outcomes. Perspec. Public Health. 2015

Kerr J., Fujiyama H., Sugano A., Okamura T., Chang M., Onouha F. Psychological responses to exercising in laboratory and natural environments. Psychol. Sport Exerc. 2006;7:345–359

Amanda Roe

Amanda Roe

Amanda is a naturopathic doctor based in Portland, Oregon. Her work jam is women’s endocrine regulation, particularly as it pertains to trail-running & endurance medicine. Amanda believes in the healing power of nature and thus gives every patient a “Nature Rx” as part of a comprehensive treatment plan. Outside work, she hits the trails before sunrise, stays warm in a rainbow terry cloth track suit, and is raising 2 half-Kiwi kids with her Kiwi husband. Visit Amanda’s website:

Trail Sisters is committed to creating opportunity and participation for women in trail running. Our content is always free to read. Consider a monthly contribution on Patreon to support Trail Sisters so we can continue to inspire, educate and empower others!


3 thoughts on “Nature’s Medicine”

  1. Know what I love about this? Everything. You know what impresses me? Seeing research from peer-reviewed scientific journals. It makes the Physiology nerd in me very happy. Great work, doc!

    • Awesome, Lisa! It’s such a joy to marry my 2 big loves, trail running and human physiology together. Pouring through the articles just about gives me an endorphin rush. So many huge benefits to trail running happening in our bodies before, during and after we do it. Let’s nerd out!


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