Shinrin-Yoku has been popular in Japan since the 80s, and in this country, too, many are looking for a short break to the rustle of leaves and birdsong. A scientific look at the healing powers of the forest walk
Can recovery from surgery be accelerated just by looking at trees? Roger S. Ulrich, clinical psychologist at the University of Uppsala in Sweden, wanted to know more about this and carried out an interesting study back in 1984: He transferred patients who had just recently undergone gallbladder surgery to a hospital room that had only a single window. With one look through this window, half of the patients could see a row of trees inside, the other half only looked at a brick wall. The results of the study were available after just a few days: the patients who looked out at the trees needed significantly less painkillers and could be discharged from the hospital a day earlier.
Such studies met with open ears, especially in Japan in the 1980s. At that time there was an increasing number of cases of Karoshi, the “death by overwork”. The authorities came under increasing pressure and had to come up with something to counteract heart attacks, strokes and suicides caused by high workloads and the associated stress. One of the solutions was called Shinrin-Yoku, which roughly translates as “to absorb the forest”. We also call this “forest bathing” today. This forest bathing is nothing more than a leisurely walk in the forest, during which you consciously enjoy the forest, breathe in the fresh forest air, listen to the rustling of leaves, watch the beauty of the trees in peace, watch the birds sing and take long breaks if you feel like it . Jogging and other activities such as fitness training or listening to music are taboo in Shinrin-Yoku.
And it works. So good, in fact, that Shinrin-Yoku is now recommended by doctors in Japan and Korea for the prevention of stress and various diseases of civilization, and is paid for by health insurance companies. There are now more than 60 special “forest healing paths” all over Japan. Between 2004 and 2012, Japanese authorities invested around 3.5 million euros in scientific research into the psychological and physiological effects of Shinrin-Yoku.
“Forest bathing gives you new strength”, explains Qing Li from the Nippon Medical School in Tokyo, “and can help not to get sick from stress.” Qing Li on his studies: “Forest bathing can lower blood sugar levels and blood pressure, reduce the concentration of the stress hormone cortisol in saliva and help against nervousness.”
Interestingly, the Tokyo researchers found these positive effects on health only confirmed during walks in the forest, but not during walks through a treeless city. In the second half of the noughties, Qing Li and Tomoyuki Kawada carried out a whole series of studies in which the scientists sent their test subjects on autumn walks in the forest and in the city. On the first day, the test subjects were only supposed to take a single walk of 2.5 kilometers in two hours, on the second day two such walks – each in the area assigned to them: forest or treeless city.
Research director Qing Li sums up the results: “We found that forest bathing significantly reduced the level of the stress hormones adrenaline and noradrenaline, while city walks had no such effect. The forest bathing has also significantly increased the number of natural killer cells (NK cells) in the immune system, increased their activity and also stimulated the formation of anti-cancer proteins – again in contrast to a city walk. ”The amazing thing about it: Even seven days after These effects could still be demonstrated in forest bathing, in some cases even for up to 30 days.
But where does this healing effect of the forest come from? “In our investigations, we were able to detect various phytoncides in the forest air, such as isoprene, alpha-pinene, beta-pinene and limonene, which we think play an important role,” says Li. Phytoncides are defense substances that plants produce if they are eaten by insects or attacked by harmful fungi, bacteria or viruses. Trees also release these chemical compounds into the forest air, which people then breathe when walking in the forest. So it is by no means just the pure, clean air in the forest or its high oxygen content that is responsible for positive health effects. There is a lot more in the air in the truest sense of the word.
However, research is still at the beginning when it comes to the question of how these and other substances affect the human organism in detail. But the sounds of the forest also make forest bathing or a walk in the forest a holistic experience. The silence, the quiet rustling of leaves and the singing of the birds ensure that the organism comes to rest and can recover from the omnipresent city noise. However, Qing Li does not want to overestimate the positive effects of forest bathing: “If you are really sick, you don’t need a forest, you need a doctor.”
