Date of the last update: 21.06.2022
Forest bathing (from Japanese: shinrin-yoku) undoubtedly has a positive effect on human well-being. What makes forest so beneficial for human health? First of all, these are aerobiological factors found in forest air, that is phytoncides and microbiota, combined with climatic factors: air ionisation, insolation, temperature and humidity. Find out more from this article.
Table of Contents:
- Phytoncides – the benefits of shinrin-yoku
- Essential oils and microbiota – benefits of forest baths
- Air humidity and the influence of negative ionisation
You can read this article in 4 minutes.
Phytoncides (from Greek phyton – plant, from Latin caedo – to kill) are substances given off by plants for communication and defence purposes. Plants emit them into the air to defend themselves against unwanted fungi, viruses and bacteria . The term was coined by a Russian scientist, Boris Tokin from Leningrad University in 1928 . Tokin found that some plants give off certain substances to prevent them from being attacked or eaten by various microorganisms. For example, coniferous trees, such as pine and spruce, produce alpha-pinene and other terpenoids. When a person breathes in forest air, they help the body to fight diseases. The terpenes are the main components of the air in the forest. These substances are widely used in medicine because of their beneficial effects. Anti-inflammatory effect of terpenes helps in inflammatory diseases of the skin, ears, joints and bronchi , and reduces lung irritation caused by cigarette smoke. It has also been proven that terpenes have a protective effect against liver, breast, pancreas and intestine cancers . So what time of day is most effective to benefit from forest air? Visits to the forest are especially recommended in the morning, when the amount of phytoncides circulating in the air is the highest.
Essential oils also belong to the group of terpenes. They are plant metabolites with anti-inflammatory and biocidal properties. Essential oils have been proven effective against streptococci, staphylococci, they are also known for their antiviral (cedar, juniper, sage oils), antifungal and anti-inflammatory properties. Inhaling essential oils helps in diseases related to the respiratory system, while exposing the body to their beneficial effects aids in skin diseases .
Microbiota – many microorganisms are found in the forest bioaerosol. In the modern world, people have too little exposure to these microorganisms because of excessive hygiene and antibiotics overuse, and that significantly weakens immunity and contributes to the development of allergies . A completely different species composition of these organisms is found in the urban environment – it is sterile and unnatural for the human body. Enclosed in buildings most of the time, we come in contact mainly with bacteria from other people and urban air, while we need the company of plant bacteria to stay healthy. On an ad hoc basis, in addition to spending time in nature every day, we can boost our wellbeing by inviting pot plants into our homes . Mycobacterium vaccae, a bacterium strain living in soil, is an extremely interesting microorganism. It enters the human body through the respiratory tract or food during a walk in the forest, when we collect plants and mushroom in the forest or do gardening. Scientific studies describe its beneficial influence on atopic dermatitis, asthma, psoriasis and some types of cancer . In addition, this bacterium stimulates the production of serotonin, called the feel-good hormone, and thus effectively improves mood . Healthy forest air includes bacteria, fungal spores, plant and animal particles and pollen. It is therefore recommended to avoid “excessive sterility” and to expose oneself to forest air as often as possible.
Air humidity is the water vapour content per unit volume of air at a given pressure and temperature. Indoors, the recommended relative humidity at 20 degrees Celsius is between 40–60% up to about 80%. Air humidity in the city is usually low. Unfavourable urban humidity fluctuations of several tens of percent within a few days (e.g. heat wave – heavy rain which does not accumulate in the soil, but quickly evaporates from asphalt and concrete) cause allergies and skin problems. The forest has a stable humidity and in Polish forests it is about 70-80 % (according to the Forestry Research Institute) . Other noteworthy aspects include negative ionisation, which is beneficial for people and has the highest negative values in forests, sunlight (green and blue colours are beneficial for the eye), reduced exposure to noise and fluctuations of atmospheric factors. It has been proven that anger passes more quickly when there is less sunlight, human-optimal humidity reduces fatigue, while negative air ionisation reduces depressive symptoms [11,12,13]. The more biologically diverse a forest is, the greater the benefits of being in it. There is no need to assume a specific distance or walking time, the important thing is to immerse in the forest with all our senses, as they are our gateways to knowledge.
Check out also: What can we learn from trees?
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