13, lowers blood sugar levels as well as markers of stress, increases the immune system and helps you sleep better. All of these benefits have been scientifically measured by nature-loving University of Tokyo doctor Dr. Qing Li. “.
Man is on the way to becoming an urban species. According to UN figures, the world’s urban population has increased from 746 million in 1950 to 3.9 billion in 2014. In 2050, 75% of the 9 billion people who will populate the planet will live in cities. In addition, our lifestyles contribute to making us a kind of interior, Europeans spend 90% of their time in closed spaces: bedroom, living room, office, car, public transport, cinema, etc.
This way of life, far from contact with nature, is conducive to stress, sleep and mood disorders and more generally to disturbances in the major natural cycles of the body that help regulate our health.
The city of Tokyo, Japan, is the most populated city in the world with 13.5 million inhabitants and a population density of 6158 inhabitants per square kilometer, against 2844 for Paris for example. The overdensity of the population, the long journeys of commuters to get to work, exhaustion from stress and the almost exclusive activity of staying all day in front of a screen mean that Tokyoites bear the full brunt of the phenomenon of burnout, work exhaustion, depression and screen addiction.
First come into contact with the forest with your 5 senses
This is one of the reasons that prompted Dr. Qing Li, a medical immunologist in the Department of Hygiene and Public Health at Tokyo Medical University, to look into the benefits of a seemingly innocuous ancient practice: walking in the forest. Or rather: forest bathing, which consists of bathing in the atmosphere of the forest, soaking up the forest through the 5 senses. By breathing in the smells, of the earth, of tree species, we look at the color of the leaves, of the soil, of the trunks and branches, of the flowers, by feeling on our skin the hot or cool air which passes through the foliage. , listening to the rustling of the leaves, a stream, the birds and even tasting the fresh air and the delicate aromas of the essences of trees that fill the air of the forests. When all the senses begin to open, we start reconnecting with nature.
Medical tests to make sure before and after a walk
Dr. Qing Li carried out, between 2004 and 2012, scientific tests on volunteer populations through saliva tests, urine tests, blood tests before and after a forest bath. The results showed a drop in cortisol, the main stress hormone, a strengthened immune system for “swimmers”, with in particular an activation of NK (natural killer) cells, sentinels which are responsible for destroying cancer cells. He also found reduced blood pressure, lower blood sugar levels, improved concentration and memory, and improved cardiovascular and metabolic health. The walkers in the forest also all reported an improvement in their quality of sleep and a better recovery from fatigue.
The more trees there are, the better it works
For the medical researcher, this is not magic. Trees act on the body through phytoncides, molecules they release into the air to defend themselves against bacteria and fungi, and which humans absorb through the skin and respiratory tract when they walk in the forest. This effect is also noticeable in city parks. All plants have a positive action. Some, however, are more powerful than others. Cypresses thus diffuse the greatest quantity of phytoncides. And the greater the tree density, the greater the benefits.
Two hours in the forest: benefits for a week
It is important to enter a forest with a different state of mind than walking down the street with your eyes glued to your smartphone. It is possible to go there alone, as a couple, with family, with friends or on a walk accompanied by a botanist. No need to hug the trees as we sometimes hear. The only imperative is to be present with all your senses. Two hours of walking in a wood has positive effects for about a week.
Read to know everything
“Shinrin Yoku, the art and science of forest bathing” by Doctor Qing Li (First, 320 p., €17.95)