It feels good to take a step outside, look at the trees and clouds and feel a shift in perspective. Studies have shown that exposure to greenspace and nature decreases stress, decrease cardiovascular disease, decrease mortality, boosts immune function, improves mood. Even seeing the color green in color psychology has been associated with calm, nature, growth and enhanced visual creativity.

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Originating in Japan, an immersive forest bathing trip is called “Shinrin-yoku”. This is a leisurely stroll in a forest where one takes in and connects with nature through the five senses. Find a quiet, tree-filled space, take your time to absorb the trees and nature, breathe deeply to take in the smells and clean air, and clear your mind and meditate.

Japanese adults were taken on a three day, 2 night retreat in the forest and their natural killer cell (a type of immune cell that kill cancer cells and destroy viral infected cells) number and activity were boosted significantly (increased by 50%!), stress markers salivary cortisol and urine adrenaline and noradrenaline decreased. These effects lasted between 7 to 30 days. Natural killer cells are commonly suppressed after traditional chemotherapy, so it’s important that forest bathing has been found to boost their activity and number. The same individuals went walking in an urban environment and these effects were not found. Even anticipating and planning a walk in nature decreased cortisol levels. While a 3 day retreat sounds lovely, additional studies have shown that you don’t have to go away for a long time. Walking once a week in a forested park for 2 hours in the morning and evening boosts your natural killer cells and that the effect can last for up to a month. Obviously, the longer you walk in nature the more benefit, but be encouraged that healthy young women walking for just 15 minutes in a forest had increased parasympathetic nervous system activity (resting and digesting response) and decreased anxiety, depression, fatigue, confusion and anger. And just thinking about walking in nature can decreases cortisol levels.

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Female breast cancer survivors recovering from chemotherapy typically have depleted natural killer cell levels and activity. One study took breast cancer survivors after chemo on a 14-day retreat living in cabins, participating in group activities, and hiking in the woods for 2 hours a day. Researchers measured their natural killer cells and anti-cancer proteins perforin and granzymes before, during and after the retreat and found significant increases in all measurements. 

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One way trees boost the immune system is through the release of wood oils called phytoncides (pinene, limonene) into the air, which we breathe in and can be detected in our blood at elevated levels after walking in a forest. These phytoncides have been shown to boost Natural killer cell activity and anti-tumor anti-oxidative effects in vivo (in cells in a petri dish).

A single blinded randomized control study studied the effect of phytoncides on gynecologic cancer survivors (cervical, ovarian, or breast cancers with a survival rate of less than 5 years). The study showed that laying down in a closed room scented with 3-5 drops of Japanese cypress wood oil (Chamaecyparis obtusa) for 1 hour a day for 5 days for 8 weeks had significantly improved parasympathetic nervous system activity (measured by reductions in stress hormones epinephrine and cortisol) and increased number of natural killer cells compared to the control group.  

 

While in nature, you can also practice grounding, a technique used to electrically connect you through physical contact to the Earth. The many studied benefits of grounding include improved immune function, blood flow, sleep, healing, energy and decreased stress, blood pressure and inflammation. This is particularly helpful if you’ve been working on a computer or in a medical facility all day and perhaps feeling overstimulated. Simply remove your shoes and press your bare feet (or hands!) into the grass or dirt*. (If you are immunocomprised and/or in active therapy, check with your medical provider before gardening or barefoot walking and exposing yourself to microbes in the soil which your body might not be equipped to handle right now.) Moisture helps facilitate this process so try sinking your feet in a stream, river, ocean pond or muddy trail. There are even barefoot walking parks in Europe (and some provide a place to store your shoes and wash your feet afterward!). Walking barefoot also stimulates Chinese acupressure points that are used in reflexology.

Simply looking at a plant can boost recovery. A study in 1984 showed that patients recovering from surgery in hospital rooms with a tree view healed faster, needed less pain medicine, had better interactions with nursing staff, and had fewer post surgical complications than those with a brick wall view. Lower pain, anxiety and blood pressure were seen in patients recovery from surgery when they had ornamental plants in their hospital room. Indeed, heart surgery patients recovering in intensive care had less pain and were less anxious when shown pictures of nature (trees and water or forest) than an abstract picture or no picture. This is why many medical facilities have green plant walls, healing gardens, aquariums, nature views, and hang artwork depicting nature scenes.

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Many of us in North America exists in boxes. We live in box shaped houses. We drive box shaped cars. These boxes contain many right, sharp angles. When we go outside, we literally step outside the box and see that nature does not like these sharp, neat angles. Nature is curvy and unpredictable. When we see curves, we feel more calm and relaxed. In a study examining curved vs linear realistic living room images, subjects reported that contoured images were more beautiful, restful, and pleasing and associated with lower stress. Get outside the box, and explore the soothing curves!

 

At your next appointment, while recovering, or on a tough day, go out and experience nature, sit next to a window or picture of nature, or pause mindfully by a plant and take in the healing energy.