Forest Bathing Benefits
The Coronavirus pandemic has caused the world to come to a halt; increasing anxiety and stress levels with it. I don’t need to be the one to explain to you the detrimental effects of high-stress levels. It’s pretty obvious that we are burnt out as a society. At the beginning of the pandemic, people welcomed the slower lifestyle. The hamster could finally hop the wheel and relax. It felt good to sleep in and pause. Unfortunately, the fast-paced, busy lifestyle will return. And we will have to hop on the wheel again. So it is essential we find a way to cope with the chaos that is life. For me, hiking has been just that.
For the last month, I have gone hiking every Sunday. At the end of each trip, my mind and body are relaxed and content. The mindless chatter is quieted. I am at peace with myself and others. For me, hiking is therapy. I know it sounds like pseudoscience, but there’s actually research to back these experiences. I wasn’t always a believer though. I would have called you crazy if you told me walking in the forest can reduce stress and strengthen the immune system. But guess what? It might just do that.
“Humans have spent over 99.99% of their time living in the natural environment. The gap between the natural setting, for which our physiological functions are adapted, and the highly urbanized and artificial setting that we inhabit is a contributing cause of the “stress state” in modern people.” -Song et al 2016
Forest Bathing
When was the last time you went hiking in the woods?
Forest bathing, also known as Shinrin-yoku, is a common practice in Japan where you take in the forest atmosphere through all of your senses. And no, you aren’t taking a shower in the woods or bathing yourself in some swimming hole. You are just walking through the woods, breathing in fresh, clean air. It is that easy. The simple practice of exposing yourself to nature will induce a state of relaxation, which may help strengthen a weakened immune system. A review of 52 studies found nature therapy to have the following benefits (1):
Reduced stress levels
Reduced blood pressure
Reduced heart rate
Improved immune function
Strengthens Immune System
Ditch the $5 immunity shot from Whole Foods and take a walk through the woods instead. Your wallet and body will thank you. Li and colleagues took twelve males with weakened immune systems (35-55 years old) and had them practice two days of forest bathing. To measure the effects on the immune system, natural killer (NK) cell activity levels were taken each morning. On day one, they walked for two hours in the afternoon covering 1.5 miles. For day two, they repeated the protocol in the morning and afternoon totaling 3 miles for the day. Both days showed an increase in NK levels, but the second day had the highest increase (2). And yes, the benefits have been shown to be experienced by females too (3).
“Natural killer (NK) cells are part of the innate immune defense against infection and cancer, and are especially useful in combating certain viral pathogens (4).” - Jordan S. Orange MD, PhD
Was it walking or the forest?
When I first came across the study, I questioned the validity. After all, a daily walk can improve one’s health. To phase out the effects of walking, Li and colleagues performed the same protocols in a city and forest. At the end of the study, the immune system increased significantly in the forest group, whereas the urban walkers didn’t experience any increases. And guess what! The immune-boosting benefits lasted a whole month(5). Excuse my excitement, but I think that is really cool.
What magic lies in the forest?
When you go hiking in the forest you are exposing yourself to these magical fairies called, phytoncides. As you walk through the woods they bless your skin with a force field, capable of deflecting any virus or germ.
Just kidding.
But wouldn’t that be cool if it was true?
In reality, phytoncides are organic antimicrobial compounds found in plants and trees. They produce these substances to protect themselves from harmful life forms, like insects.
There are very low levels of phytoncides in urban areas compared to natural environments. Many of the benefits to forest bathing may be due to the high levels of these compounds (3,4,5). To test the theory, scientists had twelve people (37-60 years old) stay in a hotel room for three nights. The researchers vaporized essential oils in the rooms to mimic the phytoncide levels from nature. By the end of the study, stress levels reduced and immune function strengthened (6).
Phytoncides, such as alpha-pinene and beta-pinene, were detected in the hotel room air. These findings indicate that phytoncide exposure and decreased stress hormone levels may partially contribute to increased NK activity -Li et al 2009
Once a Month
Based on the studies above, you can obtain the minimum benefits of forest bathing by going for a hike once a month.
Not to shabby, right?
But if you are like me and you want to maximize the benefits, I highly recommend being in nature once a week. If you don’t have any trails nearby, then go for a walk through a park. Do your mind and body a favor, bathe in the forest air.
References
Song C, Ikei H, Miyazaki Y. Physiological Effects of Nature Therapy: A Review of the Research in Japan. Int J Environ Res Public Health. 2016;13(8):781. Published 2016 Aug 3. doi:10.3390/ijerph13080781
Li Q, Morimoto K, Nakadai A, et al. Forest bathing enhances human natural killer activity and expression of anti-cancer proteins. Int J Immunopathol Pharmacol. 2007;20(2 Suppl 2):3‐8. doi:10.1177/03946320070200S202
Li Q, Morimoto K, Kobayashi M, et al. A forest bathing trip increases human natural killer activity and expression of anti-cancer proteins in female subjects. J Biol Regul Homeost Agents. 2008;22(1):45‐55.
Orange JS. Natural killer cell deficiency. J Allergy Clin Immunol. 2013;132(3):515‐525. doi:10.1016/j.jaci.2013.07.020
Li Q, Morimoto K, Kobayashi M, et al. Visiting a forest, but not a city, increases human natural killer activity and expression of anti-cancer proteins. Int J Immunopathol Pharmacol. 2008;21(1):117‐127. doi:10.1177/039463200802100113
Li Q, Kobayashi M, Wakayama Y, et al. Effect of phytoncide from trees on human natural killer cell function. Int J Immunopathol Pharmacol. 2009;22(4):951‐959. doi:10.1177/039463200902200410