Forest Bathing, that is, spending a leisurely trip in the forest for the quiet atmosphere, relaxation, beautiful scenery, and clean fresh air has become increasingly popular. It’s often known as Shinrin-Yoku, after the Japanese name, but it’s an activity that’s carried out all over the world.
Spending time in a forest has many physical and mental health benefits, about which you can read more in our general post about Forest Bathing. However, in this post, we’ll focus specifically on certain volatile substances, called Phytoncides (wood essential oils) or Forest Volatile Organic Compounds (VOC or FVOC), which you breathe in while spending time in the forest.
The highest concentrations of phytoncides are found in coniferous forests, although phytoncides are emitted by all types of forests. The main compounds of phytoncides are pinene, cineole (eucalyptol), terpinene, tamphene, sabinene, myrcene, camphene, and limonene, which are types of terpenes (a kind of organic compound produced predominantly by plants).
Phytoncides have antibacterial, antifungal, anti-inflammatory, and antioxidant properties which help plants fight disease, signal each other of threats, or attract beneficial animals. When people breathe them in (they float in the air in forests), the body increases the number and activity of a type of white blood cell called Natural Killer cell or NK-cell, which is an important fighter in our immune system. This type of cell can destroy potential threats and pathogens, while also kill cells that are infected by tumors and viruses.
Additionally, phytoncides have shown to improve people’s mood and sleep quality, protect respiratory health, have an emotionally calming effect, and lower blood sugar levels.
As it is, research shows that people who engaged in Forest Bathing days had significant higher quantities of NK-cells than those who did not. Moreover, the increased NK activity lasts for more than thirty days after a forest trip. By contrast, people who visited the city as a tourist did not show increased NK-cells activity.
Nevertheless, the concentrations of phytoncides in the forest air are affected by different factors, such as the temperature (30 degrees Celsius is said to be the optimum temperature), the type of forest (which plants and trees it primarily contains), and the time of year. In addition, the duration of a stay in the forest i.e. the exposure time to phytoncides makes that not all Forest Bathing trips have the same effect.
Moreover, the beneficial psychological and physiological of Forest Bathing cannot be exclusively attributed to inhaling phytoncides, but are rather due to the integrated and holistic physical, emotional, and mental experience of spending time in Nature, which, besides its “natural Aromatherapy” is influenced by the specific characteristics of the natural environment and the relational affinity with a specific forest of the person engaged in the activity.