Eric Hopton for redOrbit.com – Your Universe Online
The idea that walking in a beautiful natural environment is better for the mood than walking in a traffic-filled city seems like a no-brainer.
But is there a scientific basis to the difference, and is it quantifiable? Research from Stanford University suggests the answer to both questions is yes. The study found substantive evidence that walking in nature can lower the risk of depression.
“These results suggest that accessible natural areas may be vital for mental health in our rapidly urbanizing world. Our findings can help inform the growing movement worldwide to make cities more live-able, and to make nature more accessible to all who live in them,” said co-author Gretchen Daily, a senior fellow at the Stanford Woods Institute for the Environment.
Urbanization and mental illnesses
As more and more people concentrate in the world’s sprawling towns and cities, urbanization and the subsequent “disconnect” from nature are increasingly associated with the rising incidence of mental disorders like depression, anxiety, and mood disorders like schizophrenia.
The study involved two groups of participants walking for 90 minutes, one in a grassland area adorned with oak trees and shrubs, the other along a traffic-heavy four-lane roadway. Before and after the walks, the researchers measured heart and respiration rates, performed brain scans, and had participants fill out questionnaires.
Analysis of the results showed little difference in physiological conditions between the groups. It was a very different story when the brain scans were examined. Among the “nature walkers,” neural activity in the subgenual prefrontal cortex (sgPFC), decreased significantly. (The sgPFC is an area of the brain region active during rumination, a repetitive focus on negative emotions.)
“This finding is exciting because it demonstrates the impact of nature experience on an aspect of emotion regulation – something that may help explain how nature makes us feel better,” said lead author Gregory Bratman.
“These findings are important because they are consistent with, but do not yet prove, a causal link between increasing urbanization and increased rates of mental illness,” said co-author James Gross, professor of psychology at Stanford.
“We want to explore what elements of nature – how much of it and what types of experiences – offer the greatest benefits,” said Daily.
In a previous study, also led by Bratman, time in nature was found to have a positive effect on mood and aspects of cognitive function, including working memory, as well as a dampening effect on anxiety.