Spending just an hour in nature could reduce stress in the brain

Spending just an hour in nature could reduce stress in the brain

Everyone has been able to notice on their own scale that walking in green spaces often provokes a feeling of well-being, relaxation and appeasement. In this area, it is well known that living close to nature is beneficial for mental health, while living in the city is a risk factor for developing a mental disorder, as the environment there is made up of significant stress factors ( pollution, visual and auditory nuisance, etc.). But how to explain that these walks in the open air do so much good to our brain? It is to better understand this relationship that researchers from the Max Planck Institute have taken an interest in a central region of the brain involved in the processing of stress: the amygdala. Why this area? It has been previously shown that the amygdala is more active in urban people than in those living in the countryside, and given its important role in the processing of emotions, that it would act as an important marker of stress.

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Their study published in the journal Molecular Psychiatryinvolved examining brain activity in this area in 63 volunteers before and after an hour-long walk in the Grunewald forest or on a busy shopping street in Berlin using a test called magnetic resonance imaging functional. The goal: to search for the presence of possible markers of stress via activity within the amygdala. The results revealed that the latter seemed to decrease after walking in nature, suggesting that green spaces are likely to cause direct beneficial effects on brain regions related to stress. ” These results support the previously assumed positive relationship between nature and brain health, but this is the first study to prove causation. Interestingly, brain activity after urban walking in these regions remained stable and did not show an increase.“Explains Professor Simone Kühn in a press release.

Mental illnesses, a public health issue in their own right

Good news: this observation therefore goes against the generally accepted idea that urban exposure causes additional stress. For the scientific team, the fact that even a short exposure to nature can decrease the activity of the amygdala suggests that a simple walk in nature could serve as a preventive measure against the development of mental health problems, and even cushion the potentially detrimental impact of city life on the brain. Another good news, this positive impact on the regions of the brain involved in the treatment of stress is therefore already observable after an hour of walking. While further studies are needed on a larger panel of participants to more precisely determine the mechanisms involved, these early findings could have a big impact on how mental health issues are treated. And for good reason, it is indeed one of the leading causes of disability worldwide according to estimates by the World Health Organization (WHO).

Furthermore, these results are in line with a previous study published in 2017 in the journal Scientific Reports by the same team, having demonstrated that city dwellers who lived close to the forest had a physiologically healthier amygdala structure and were therefore presumably better able to cope with stress. “ This new study confirms once again the importance for urban planning policies of creating more accessible green spaces in cities in order to improve the mental health and well-being of citizens. “, conclude the researchers. Their next step will be to study the beneficial effects of nature in different populations and age groups, which is why they are currently working on a study examining how a one-hour walk in natural environments compared to urban environments affects stress in mothers and their babies. It should be noted according to the WHO that mental illnesses affect more than one in eight people in the world.