Based on brain imaging, researchers from the Max Planck Institute were recently able to clearly demonstrate that a one-hour walk in the forest reduced the activity of a region of the brain that deals with stress, compared to to a walk of the same duration in a bustling urban environment.
For decades, researchers have reported myriad differences in mental health between people living in rural and urban settings. While it is clear that spending time in natural environments can be beneficial, several questions regarding the association between nature and relaxation went unanswered. For this new study published in the journal Molecular PsychiatrySonja Sudimac and her colleagues sought to determine precisely whether urban environments were actually causing more stress or if the fact of evolving in natural environments reduced it.
The team recruited about sixty volunteers. When they arrived at the lab, each of them underwent an MRI scan during which the activity of the amygdala was monitored during several tests measuring reactions to stress. Once these measurements were taken, the subjects were invited to take a 60-minute walk in town or in the forest. The urban route ran along a busy street in Berlin, while the natural route ran through a nearby forest. At the end of the walk, the participants returned to the laboratory, and their stress response was again examined.
In all tests, a significant decrease in amygdala activity was detected in subjects who spent one hour in a wooded environment, when no change could be demonstrated in the others. This indicates that urban exposure does not necessarily increase a person’s stress responses, but that time spent in nature helps to dampen this type of neural activity.
More green spaces to promote the mental health and well-being of city dwellers
Such findings echo previous research. In particular, these had shown that mental health could be linked to proximity to nature, with city dwellers living near green spaces or wooded areas showing physiologically healthier amygdala structures and also less likely to experience loneliness.
According to Simone Kühn, of the Lise Meitner Group for Environmental Neuroscience, these various works underline the need to integrate more green spaces in urbanized areas to promote mental health and well-being. ” If this study confirms the previously assumed positive relationship between nature and brain health, it is the first to establish a causal link. concludes the researcher.