We have all experienced good health while walking in nature. Is this impression supported by science? How does the environment affect the brain? Answers with Michel Le Van Quien, INSERM researcher.
Struck by the lack of nature during his first imprisonment, INSERM researcher Michel Le Van Quen became interested in scientific research into the beneficial effects of nature on our brains. The guest of the “La Terre au carré” program, Mathieu Vidara, shared his findings with Camille Cronier.
Nature: what are the benefits?
Michel Le Van Kuen explained:
In large cities, the risk of mental illness, mood disorders and anxiety increases by 30%.
A major Dutch study in 2009 looked at the medical records of 350,000 people. She found that good health, and especially good mental health, declined the further one moved away from home to city parks. Beyond 400 meters there is a greater risk of mental illness.
Mental health, but not only
These results were confirmed by an American study at the University of Chicago, which goes even further and confirms that the more trees you have nearby, the less heart disease, diabetes, and antidepressant use you have.
Tokyo Medical University was very interested in the influence of the forest on the connection between the forest and the immune system. This goes through the smell of resinous trees (limonenes, terpenes, etc.). Researchers have shown that they act on NK cells (natural killer cells) that kill diseased cells in our body, such as those infected with viruses or cancer cells.
The number of NK cells increases by about 50% during a day’s walk in the forest!
Better Learning Ability
In 2015, 3,000 children in Barcelona took part in the study. Every day, the degree of impact of children on natural landscapes was measured.
A year later, the researchers realized that the children most exposed to the environment had the best working memory.
How it works ?
When we walk, we forget about technology a little. Allowing nature to come to you already has a very beneficial effect on mental health. Moreover, during the Japanese experiment, when we showed a person images of nature, his brain calmed down.
According to the researchers, this calmness could be explained by the fact that life in the city is recent – it is only 200 or 300 years old. And this modern life requires a lot of effort to adapt, which creates stress. This is why immersion in nature soothes us.
Impact on our second brain
When gardeners dig up the ground, they often have a certain feeling of euphoria. According to some researchers from the University of Bristol, this euphoric effect may be due to contact with certain bacteria, such as Mycobacterium Vaccae. Absorbed through the skin or inhaled, they are integrated into the microbiota of our intestines. This bacterial factory creates neurotransmitters such as serotonin, which has a strong antidepressant effect.
Nature entertains our thoughts
Another study published in the journal Science and with 3,000 participants showed that most of the time we were thinking about things that had nothing to do with what we were doing. Very often these thoughts are negative.
On the other hand, if you are in front of a window, if you look at the sun or nature, it prevents you from thinking.
Your attention is focused on the environment and allows the brain to regenerate. This is one of the phenomena that explain the beneficial effects of nature.
The sea too
Finally, another study found that there were generally fewer mental health problems at sea than on land. The sea is a calming element. The amygdala is a structure that has been programmed from time immemorial to respond on the fly, to every unforeseen sign.
Thus, being in front of an extremely calm structure calms it down and allows you to enjoy the benefits of the environment. In addition, blue is a particularly auspicious color for creating a state of well-being.
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Michel Le Van Quen, Director of Research at Inserm, works in the Biomedical Imaging Lab. (LIB)Author Brain and Nature, why do we need the beauty of the world (Editions of Flammarion)