The power of green | Inquirer Opinion

The power of green

At the Children’s Hospital in Oakland, California, physician-educator Nooshin Razani is training pediatricians in the outpatient clinic to write prescriptions for children and parents to visit parks in their community. This is not as easy as writing a prescription for the antibiotic amoxicillin.

To accomplish this new task, the pediatricians had to alter the design of their hospital. Maps were put on the walls showing the nearest parks so that parents and their children could find these without difficulty. Pictures of local wilderness became part of the walls, too. And the hospital partnered with the East Bay Regional Parks District to provide rides to the parks as well as the venues for family programs.


Why the change in medical practice? Why prescribe a visit to parks and nature? The pediatricians at the Children’s Hospital had noted the growing cognitive research on the effect of nature on the brain and mental health.

David Strayer is a cognitive researcher from the University of Utah and an avid backpacker. His study is on attention and the effect of multitasking. In a study of outward-bound participants, he found that a three-day nature immersion of his subjects brought about 50 percent improvement in creative problem-solving tasks. With the use of a portable EEG (electroencephalogram) that measures the electrical activity of the brain, he showed that after the nature encounter, lesser energy was emanating from the “midline frontal theta waves.” It was a good outcome, indicating that the brain was not exerting lots of effort to solve a problem.


Researchers from the University of Exeter Medical School in England recently studied the mental health of 10,000 city dwellers and used high-resolution mapping to track the subjects for 18 years. It was found that people who lived near areas with green spaces had lesser mental illnesses even after adjustments for education, employment and income.

In 2009 a group of Dutch researchers found a lower incidence of 15 diseases (including anxiety, depression, diabetes, heart disease, asthma and migraine) among people who lived within half a mile of nature spaces.

Last year an international team of researchers studied health questionnaire responses from more than 31,000 residents of Toronto, Canada. Using a map, they correlated the responses block by block in the city. They found that those living in blocks with more trees showed a boost in heart and metabolic health equivalent to a $20,000 gain in income. A lower death rate and less stress hormone in the blood of those living close to green spaces were also demonstrated.

From the University of Glasgow in Scotland, Richard Mitchell, an epidemiologist who studies the relationship between population and health, found that the effect of living near nature was sufficiently restorative, with no need to walk in the area. In this study, Mitchell showed that the lowest-income people seemed to gain the most.

Matilda van den Bosch, a physician in Sweden, found that students who took a math test had their heart variability decreased with stress. Those students who sat for 15 minutes with nature scenes and bird song in a 3-D virtual reality room had their heart pattern returned to normal quicker than those who sat in a plain room.

In another experiment at Snake River Correctional Institution in eastern Oregon, officers reported that prisoners showed calmer behavior in solitary confinement who exercised for 40 minutes several days a week in a “blue room” where nature videos were played than those without such videos.

Japanese researchers led by Yoshifumi Miyazaki at Chiba University sent 84 experimental subjects to walk around in seven different forests; an identical number of volunteers walked around city center blocks within the same period. The forest walkers showed a 16-percent drop in the cortisol stress hormone, a 2-percent drop in blood pressure, and a 4-percent drop in heart rate. Miyazaki thinks that our bodies relax in a green environment because we evolved from there and not from high-rise building and traffic.


Because of these new findings in the positive benefits of parks, some countries are using the outcome in formulating public health policy. In Finland, which has high rates of suicide, alcoholism and depression, government-funded researchers asked thousands of Finns to rate their stress and mood levels after a visit to parks and urban areas. From these studies, Prof. Liisa Tyrvainen and her team at the Natural Resources Institute Finland recommended a five-hour-a-month nature walk for Finland’s citizens.

Another country that has embraced the healing power of parks is South Korea. At the Saneum Healing Forest east of Seoul, a “health ranger” offers elm bark tea, a hike along a small creek, red maples, oaks, and pine-nut trees to visitors.

Based on new research, we should design houses, schools, hospitals and office buildings with walls painted or decorated with green grasses, plants, trees, blue skies, oceans and rivers. And if possible, real plants and trees should be grown in containers inside the buildings.

Dr. Leonardo L. Leonidas ( retired in 2008 as assistant clinical professor in pediatrics from Boston’s Tufts University School of Medicine, where he was recognized with a Distinguished Career in Teaching Award in 2009. He is a 1968 graduate of the University of the Philippines College of Medicine and now spends some of his time in the province of Aklan.

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TAGS: health, Mental Health, outdoors, Parks
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