Forest Bathing Enhances Natural Killer Cell Activity

Posted on Aug 11, 2020 in Depression, Diabetes, Heart Disease, Natural Health, Nutrition

Forest Bathing Enhances Natural Killer Cell Activity

Any devastating, life threatening disease, mankind has been in a constant search of a cure. Cancer has plagued citizens – especially those of modern industrialized countries – for generations.  When pharmaceutical  intervention took place, disease therapies  rapidly concentrated on expensive drugs and less than ideal treatments of which can be more harmful to the patient. This protocol has become the standard  treatment plan in Western medicine. Other countries and civilizations employ a variety of health treatment modalities such as naturally sourced medicine, clinical nutrition, outdoor health therapies and  extra supplementation  to pick up insufficient diets  and more.

One main focus of this piece will be our body’s anti-cancer ability, demonstrating its ability to boost our natural killer cells that immediately recognize cancer cells and destroy them.  This approach has been scientifically proven in Japan – called Forest Bathing.  Shinrinyoku or forest bathing has been practiced for thousands of years in Japan.

We live in a time where the average person spends inordinate amounts of time indoors; a whopping 87% while another 6% is spent in our vehicles. Continuing on at this pace, by 2050, approximately 2/3 of the world’s population will occupy urban centers. (1,2)

Most would agree that time spent outdoors, close to nature (not in the city) provides many health benefits. And a sedentary lifestyle offers its own set of problems.

Unlike its description, forest bathing does not involve water. Instead, imagine a relaxing, leisurely walk through the forest. Not at all resembling strenuous exercise, simply enjoying peacefulness, aromatic smells in the air, and observing nature in its daily activities. Forest bathing has been practiced for centuries in Japan to relieve stress and improve mood and energy.

However tests performed for nearly 40 years by the Forest Agency of Japan; whereby researchers conducted a Profile of Mood States test presented significant reduction of depression, anxiety and anger. (3)

Prevention of cancer generation and development

Forest bathing boosts our immune system and prevents cancer, in addition to enhancing moods and energy, it lowers inflammation, helps regulate blood sugar and lowers blood pressure (hypertension).

How Does it Benefit Cancer?

Natural Killer Cells, Cancer, and the Immune System

In order to understand how this activity raises our natural killer cells – benefiting cancer and our immune system, lets first learn about natural killer cells As many of us have come to know, our immune system is our defense mechanism against disease, pathogens, and mutant cells of cancer. Mutant tumor cells can actually go undetected by our immune surveillance cells – they have the ability to disguise themselves as other cells. This in part may have to do with the fact that our immune system actually assists in the formation of tumors at a specific stage.

Natural killer cells come to the rescue. Their job is to target cancerous cells and obliterate them. (4) They are our white blood cells of the lymphatic system. They are arguably our best and first line of defense against cancer. (5)

There have been a number of studies performed over the last fifteen years, investigating the effects of forest bathing and our immune function. Resulting outcomes showed an increase in the number of natural killers cells (NK) and in their functioning activity levels. (3,5,8)

High Cortisol Levels and Cancer

There are necessary bodily functions of cortisol, similar to adrenaline, (12) but there is also a proven correlation involving chronically high cortisol levels and cancer.  Emotional stress is a main factor to the 6 leading causes of death in the United States, listed as follows:

Coronary heart disease
Accidental injuries
Respiratory disorders
Cirrhosis of the liver

Imagine, a simple walk through a forest or treed landscape, can effectively reduce stress and inflammation enough to make a marked difference in your health. (11,12,13,14)


  1. World Urbanization Prospects
  2. The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants
  3. Effect of forest bathing trips on human immune function
  4. Natural Killer Cells: How to Keep Them Healthy So They Can Protect You From Cancer
  5. Natural killer cells in human autoimmune disorders.
  7. Health effects of a forest environment on natural killer cells in humans: an observational pilot study
  8. A Forest Bathing Trip Increases Human Natural Killer Activity and Expression of Anti-Cancer Proteins in Female Subjects
  9. Psychological effects of forest environments on healthy adults: Shinrin-yoku (forest-air bathing, walking) as a possible method of stress reduction
  10. Effects of Forest Bathing on Cardiovascular and Metabolic Parameters in Middle-Aged Males.
  11. The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan.
  12. High Cortisol Levels and Breast Cancer: What’s the Connection?
  13. The Association between Self-Reported Major Life Events and the Presence of Uterine Fibroids
  14. Shinrin-Yoku (Forest Bathing) and Nature Therapy: A State-of-the-Art Review
  15. Health Effect of Forest Bathing Trip on Elderly Patients with Chronic Obstructive Pulmonary Disease.
  16. Shinrin-yoku (forest-air bathing and walking) effectively decreases blood glucose levels in diabetic patients.
  17. Blood pressure-lowering effect of Shinrin-yoku (Forest bathing): a systematic review and meta-analysis.
  18. Heart Disease in the United States

Copyright © 2020 – All Rights Reserved – Michelle Honda Ph.D.


Look for my new forthcoming books “Reverse Depression Naturally” (Spring 2020) “Reverse Inflammation Naturally” (May 31, 2017) “Reverse Thyroid Diseases Naturally” (June 2018) “Reverse Alzheimers/Dementia Naturally” (Nov.2018)  “Reverse Heart Disease Naturally” (Jan.31, 2017) and “Reverse Gut Diseases Naturally Nov. 2016

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While close attention was given to the accuracy of information in this article, the author accepts neither responsibility nor liability to any person with respect to injury, damage, loss or any circumstances involving alleged causes directly or indirectly related to the information in this article. The sole purpose is to educate and broaden ones awareness. This information is not meant to replace medical advice or services provided by a health care professional.

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