Why We Benefit From Spending Time Outdoors

by Rick Casey

August 17, 2023

A program developed for Larimer County Natural Resources Department as a Volunteer Naturalist

Program outline in brief:

  • Background & motivation
  • Demonstration: sense engagement exercise
  • Research findings
  • Book show & tell: Forest Bathing by Dr Qing Li
  • Developing a personal practice
  • Discussion
  • References with reviews (see link at bottom)

Program outline in detail:

  • Introduction: spoken, giving an overview of what the program is about
  • Show the QR code for this webpage: for people with a smartphone, they can scan the code; give a handout with the URL to anyone without a phone.
  • Brief introductory exercise: ice-breaker breath & vision exercise, a guided meditation meant to transport the participant to a calmer state 
  • Main Talk: longer explanations of these subtopics:
    • Stress is unavoidable in modern urban life:
      • Continuous noise (example: urban environment)
      • Continuous negativity (news, social media)
      • Driving in traffic
      • Overstimulates the sympathetic nervous system 
    • Harmful effects of low level, continuous stress can be counteracted in a self care program
    • Benefits of developing a personal Nature program: physical, mental, medical
      • ‘Nature deficit disorder’ is a real thing: prolonged absence of experiencing Nature through our senses has negative health effects
      • Physical benefits: lowered stress level means improved immunity
      • Mental benefits: quieting your mind brings calmness and improves decision making
      • Medical benefits: there are beneficial chemicals we absorb from plants
    • Science: recent research findings & historical evidence
      • Beneficial chemicals from trees & plants
      • Local examples of beneficial plants (via airborn chemicals)
    • Guide to designing your practice:
      • Location & setting
      • Duration
      • Exercises: using the senses separately to focus on each
      • Regularity of practice
    • How a deeper connection to Nature connects us to our evolutionary past & indigenous cultures
    • Review of references & further self study
  • Wrapup

Benefits summary:

Physical Benefits, short term:

  • Lowered stress (indicated by lowered cortisol levels)
  • Lowered heartrate

Physical Benefits, long term:

  • reduced risk of cancer
  • helps prevent or alleviate depression
  • longer term calming effect on sympathetic nervous system
  • parasympathetic nervous system benefits (digestion and rest)
  • improved sleep cycle (regularity)
  • deeper rest from sleep

Mental Benefits:

  • Lowered confusing thoughts
  • Sympathetic nervous system benefits
  • Stronger sense of well being, resulting in increased self-confidence

  1. Introduction

This program is about how just being out in Nature is good for your physical and mental health; a further hypothesis is that it helps to “ground” our sense of well being due to our evolution as biological organisms. This has been treated as common knowledge; but there is growing scientific research about how and why it is beneficial. The effects are so beneficial for nature-deprived individuals, it suggests that spending time in Nature is essential and irreplaceable to enjoying full health. Based on this research, it shows that you can design your own program to de-stress from an urbanized, largely indoor existence. Such a weekly program can boost your immune system, calm and clear your mind, and, over time, build your personal connection to Nature. By the end of this program you should have the information to design your own personalized approach on how to get the most out of your connection to Nature experience – or, as I call it, Nature bathing. 

Brief introductory exercise

This short breathing exercise will help us get started on our connection to the natural environment. 

Close your eyes. Focus on your breath and your hearing. Take in a long slow breath…maybe silently counting slowly to four…then exhale to the same count. Take two breaths like this…then stop counting, and just listen. 

Listen for 5 minutes with eyes closed. 

Pick out how many different natural sounds you can hear: wind? water? bird songs? Focus on these sounds, forgetting all other thoughts. 

Set a timer for 5 minutes. When you slowly open your eyes, what is the first thing you notice visually?

Think about what you listened to during the 5 minutes of silence: what was the most interesting sound? 

Main Talk: How We Experience Nature

We experience Nature through our senses, of course, so to have an effective connection we should focus on our each of our senses separately. 

We focused on the senses of sight and sound during the introductory exercise. Our other senses are touch, smell and taste.

Feel: our tactile sense is one of our most detailed senses, and reinforces memory. Touch the plants around you…feel the bark of the trees, the leaves of the bushes, the stalks of grass. If there are rocks, brush your fingers over them. If you are in safe place to do so, walking barefoot can increase your tactile connection to the environment. All such direct sensory experiences are more than they appear on the surface, because such direct connections to Nature evoke a deeper reaction than we are consciously aware. 

The Origins of Shinrin-Yoku

Shinrin-yoku is Japanese for ‘forest bathing’, a term coined in 1982  by Tomohide Akiyama, then director of Japan’s Forest Agency. Rooted in ancient Japanese beliefs from Shintoism about the need for harmonic balance with Nature, it has been the scientific approach of these government agencies that sparked global interest in the topic, started a movement that has taken hold in many countries, and built a firm foundation of the health benefits of the practice. I suspect the pragmatic Japanese government has recognized the value of investing in Shirin-yoku as a means to boost the public health of its heavily urban population. 

There are even Recreation Forests dedicated to shinrin-yoku, spread all over Japan: 1,055 as of 2016 (see documentation here). Also, see the book I brought to show: Shinrin-Yoku by Dr Qing Li.

South Korea has also invested heavily in the benefits of forest bathing, or salim yok in Korean, and developed a number of public health programs open to everyone. I found this webpage on how to do a forest bath on the South Korean Forest Agency website. (There is no such page for ‘forest bathing’ on the USFS website! However, I did find this: Walk in the woods for wellness: Health benefits of forests)

Since forests are not everywhere that Nature is, I have adopted the term “nature bathing” to describe this program. Forests are rich in biodiversity, and trees produce more abundance of certain beneficial airborne chemicals; I nonetheless believe that we can benefit from exposure to Nature wherever it is. 

Benefits of Connecting with Nature: How Tree Chemistry Aids Human Health

Trees emit phytoncides, which are natural oils that are part of a plant’s defense system against bacteria, insects, and fungi. These have been shown to benefit the human immune system.

Reduction of Low Level Stress

Low level stress is the unconscious reaction of your autonomic nervous system to perceived threats. Since these signals go through the amygdala portion of the brain, they are not part of conscious thought; the signals come in automatically, quicker than you can consciously react. If you live in an unsafe environment, stress can come from anxiety about your safety. In an urban environment, constant noise can trigger low level stress. 

Other unconscious stress can come from pollution. Polluted air; though not a mental trigger, this also serves as a trigger to the nervous system that is constantly exposed to it.   

The causes of low level stress and its consequences are a major health threat, according to many studies. Low level stress means external stimuli that triggers the sympathetic nervous system to keep releasing cortisol into your blood system. Cortisol is a chemical naturally created by the body that acts like an alarm system to help you react to a dangerous situation, increasing the heart rate, diverting blood to muscles instead of digestion, inflame the immune system and many other effects. Since cortisol can be quickly measured from saliva samples, research has proven in before-and-after measurements how spending time ‘forest bathing’ reduces the cortisol level, among other benefits. 

Low level stress is a result of being constantly ‘on alert’, which in an urbanized lifestyle, can easily start to happen to people 24/7. Worrying constantly about things you need to do — or worse, feel physically threatened by — contributes to low level stress, if we aren’t consciously aware of it. Loud noises is another reason; your body automatically reacts to this as a threat, and release cortisol as a reaction. Higher cortisol levels increases low level inflammation, which contributes to heart disease, disrupted sleep patterns, lowered resistance to infection,cancer, type 2 diabetes and even to depression. 

Coming into contact with nature can help reduce these cortisol levels. Salivary cortisol is a biomarker that can be easily tested for the effects of nature on our body, and research indicates getting out in nature reduces the cortisol level. 

[from p. 64 in Forest Bathing] Health Benefits of Forest Bathing:

  • Boost immune system
  • Increase energy
  • Decrease anxiety, depression and anger
  • Reduce stress and help you to relax

The Significance of Awe

The sense of awe in Nature, which I’m sure you all must have felt at some time, turns out to have an important function in the brain. It appears to be unique type of emotion and deeply significant, based on MRIs recorded for the purpose. Awe can be inspired by many things, but those that come from Nature seem particularly powerful. What modern science is discovering is that this unique emotion, when experienced in Nature, seems to connect us at a deeper level to a feeling of connection to the larger universe. Could this be more than just a feeling? Why should our brain react in this way? Significantly, deep experiences of awe have continued benefits even weeks after the experience. This is still a mystery to modern science, but certainly seems to warrant further study. Some progressive cities have attempted to carve out parks and spaces to experience awe during children’s play time. 

Soft fascination versus voluntary attention

(see p 110 in Forest Bathing by Li). Voluntary attention requires concentration and effort, which is why city life is stressful and tiring. ‘Soft fascination’ requires no effort, but is the kind of mental attention we experience when in pleasant natural surroundings. This has been noticed throughout history, but only recently have mental health researchers and doctors begun to document its therapeutic value in healing.

Our Evolutionary Past and the biophilia hypothesis

The biophila hypothesis was proposed by the entomologist E. O. Wilson in 1984 in a book of the same name; though the term was first coined by Erich Fromm in 1964. It basically states that humans have a deep affiliation with, and respond to, all forms of life because it is where we evolved from over millions of years. Of course, such an idea is hardly new, and has existed since Aristotle; this is simply the modern term for it. 

The idea has been taken up by evolutionary biologists and evolutionary psychologists to more deeply examine how our evolutionary past as organisms — even the very structure of our brain and nervous system — grew out of our responses to the natural environment as animals. Indeed, this forms over 99.9% of our evolutionary  existence, and is hard to deny how it was primal this influence is. 

The science of this connection to our evolutionary past has only just begun, but one fact is quite clear: the modern urban environment, if devoid of contact with nature, is unhealthy. Making contact with a natural environment easily and frequently available to all of the population should be a part of all public health policies; and, as Japan and South Korea are proving, such investments in public health have tangible benefits and help to avoid medical costs resulting from bad health. 


Developing Your Practice

These are some general suggestions for developing your own practice of getting outside regularly. there are four aspects to consider: 


If you return to a known location, you can settle into a calm state more easily. You may also start to notice details that will give you a deeper awareness. A known location will put you more at ease.


Any time spent outdoors in safe surroundings is beneficial; but a general rule of thumb is at least five hours per month. For lasting positive effects from a single outing, it seems three hours is needed.  

Exercises: focus on senses separately

Sight and sound are our main connections to the natural environment. Focusing on hearing by closing the eyes allows to focus on that; and opening the eyes after a time can allow for a renewal of awareness. Of course, feeling, smelling and tasting can extend our connection to nature in deeply moving ways. 

Regularity of practice

Developing a schedule of visiting a known location can help to deepen awareness, and heighten the senses. 

References with reviews – bibliography with notes

Summary of The Nature Fix (recommended)