Walking in a noisy city keeps our minds focused on repetitive negative thoughts - time in nature is the cure. [Photo: Bigstock]

Nature is the best prescription for stressed city dwellers

13 August, 2015

Natural Health News — A new study has found convincing evidence that supports the common-sense idea that walking in nature could lower your risk of depression.

The study, published in Proceedings of the National Academy of Science, used MRI scans to examine in a quantifiable way the effects that time in nature versus being in a busy built-up environment have on the brain.

It found that people who walked for 90 minutes in a natural area, as opposed to participants who walked in a high-traffic urban setting (in this instance El Camino Real in Palo Alto, California, a noisy street with three to four lanes in both directions), showed decreased activity in the subgenual prefrontal cortex, a brain region active during rumination — repetitive thought focused on negative emotions.

What you need to know

» More than half the human population now lives in cities, and this number is rising.

» City dwellers are more prone to mental disorders such as anxiety and depression.

» A new study has found measurable differences in brain activity between urbanites taking a walk in a city and those walking in a more natural environment.

» The scientists suggest that urban planning that included more green spaces could improve mental health for city dwellers.

Make cities more liveable

“These results suggest that accessible natural areas may be vital for mental health in our rapidly urbanising world,” said co-author Gretchen Daily, the Bing Professor in Environmental Science and a senior fellow at the Stanford Woods Institute for the Environment. “Our findings can help inform the growing movement worldwide to make cities more liveable, and to make nature more accessible to all who live in them.”

“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, a graduate student in Stanford’s Emmett Interdisciplinary Program in Environment and Resources, the Stanford Psychophysiology Lab and the Center for Conservation Biology.

An increasingly urbanised world

The study notes that more than half of the world’s population lives in urban settings, and that is forecast to rise to 70% within a few decades. Just as urbanization and disconnection from nature have grown dramatically, so has mental illness, including anxiety disorders and depression.

In fact, city dwellers have a 20% higher risk of anxiety disorders and a 40% higher risk of mood disorders as compared to people in rural areas. People born and raised in cities are twice as likely to develop schizophrenia.

Studies like this contribute to a growing body of evidence suggesting a link between city life and rising levels of mental illness.

City planners take note

According to the authors, it is essential for urban planners and other policymakers to understand the relationship between exposure to nature and mental health. “We want to explore what elements of nature – how much of it and what types of experiences – offer the greatest benefits,” says 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.