A one-hour stroll in nature decreases stress-related brain activity, according to new research.
Living in a city is a well-known risk factor for developing mental disorders, whereas living near nature is thought to be good for the brain and mental health. The amygdala, a crucial brain region involved in stress processing, has been demonstrated to be less activated during stress in individuals who reside in rural settings compared to those who live in cities, indicating new advantages of nature.
“But so far the hen-and-egg problem could not be disentangled, namely whether nature actually caused the effects in the brain or whether the particular individuals chose to live in rural or urban regions,” says Sonja Sudimac, a predoctoral fellow in the Lise Meitner Group for Environmental Neuroscience and lead author of the study.
Using functional magnetic resonance imaging (fMRI), the researchers from the Lise Meitner Group for Environmental Neuroscience monitored the brain activity of 63 healthy volunteers before and after a one-hour walk through Grunewald forest or a busy Berlin shopping street to establish a causal connection. The study’s findings showed that after taking a walk in nature, amygdala activity decreased, indicating that being in nature had a positive impact on stress-related brain regions.
“The results support the previously assumed positive relationship between nature and brain health, but this is the first study to prove the causal link. Interestingly, the brain activity after the urban walk in these regions remained stable and did not show increases, which argues against a commonly held view that urban exposure causes additional stress,” explains Simone Kühn, head of the Lise Meitner Group for Environmental Neuroscience.
The authors demonstrate that being in nature has a positive impact on the brain regions involved in processing stress and that this impact is already evident after a one-hour stroll. This advances knowledge of how our physical living environment influences our brain and mental health. Even a brief exposure to nature may reduce amygdala activity, which suggests that going for a walk in nature might help prevent mental health issues from occurring and can help to mitigate the negative effects of living in a city.
The results go in line with a previous study (2017, Scientific Reports) which showed 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 again confirms the importance of urban design policies to create more accessible green areas in cities in order to enhance citizens’ mental health and well-being.
In order to investigate the beneficial effects of nature on different populations and age groups, the researchers are currently working on a study examining how a one-hour walk in natural versus urban environments impacts stress in mothers and their babies.
“How nature nurtures: Amygdala activity decreases as the result of a one-hour walk in nature” by Sonja Sudimac, Vera Sale, and Simone Kühn, 5 September 2022, Molecular Psychiatry.
“In search of features that constitute an “enriched environment” in humans: Associations between geographical properties and brain structure” by Simone Kühn, Sandra Düzel, Peter Eibich, Christian Krekel, Henry Wüstemann, Jens Kolbe, Johan Martensson, Jan Goebel, Jürgen Gallinat, Gert G. Wagner, and Ulman Lindenberger, 20 September 2017, Scientific Reports.