16 Oct 2009

Green spaces boost body and mind

More green space may be a way for whole communities to become healthier. And the closer you live to nature, the healthier you're likely to be.

"As health-care costs spiral out of control, it behoves us to think about our green space in terms of preventive health care," said Dr Kathryn J. Kotrla, associate dean and chair of psychiatry and behavioural science at Texas A&M Health Science Centre College of Medicine Round Rock campus.

"This highlights very clearly that our Western notion of body-mind duality is entirely false. The study shows that we are a whole organism, and when we get healthy that means our body and our mind get healthy."

Dutch research shows that people who live within a kilometre of a park or wooded area experience less anxiety and depression. The findings put concrete numbers on a concept that many health experts had assumed to be true.

"It's nice to see that it shows that, that the closer humans are to the natural environment, that seems to have a healthy influence," said Dr David Rakel, director of integrative medicine and assistant professor of family medicine at the University of Wisconsin School of Medicine and Public Health.

One previous study had noted fewer health inequalities between rich and poor people in areas with lots of green space, and other studies have echoed these health benefits. But much of this research had relied on people's perceptions of their physical and mental health.

How the study was done
This new objective look at the matter involved scouring medical records of 345 143 people in Holland, assessing health status for 24 conditions, including cardiovascular, respiratory and neurological diseases. This information was then correlated with how much green space was located within one kilometre and three kilometres of a person's postal code.

People living in more urban environments had a higher prevalence of 15 of the 24 conditions, with the relationship strongest for anxiety disorder and depression.

In areas with only 10% of green space, about 2.6% of people experienced anxiety disorders, compared to 1.8% of people in areas with 90% green space. The disparity was evident for depression as well -- 3.2% of people living in more urbanised areas had depression versus 2.4% of those in more rural areas.

The health benefits were evident only when the green acres were within a kilometre, not at the three kilometre perimeter, except for anxiety disorders, gastrointestinal digestive disorders and so-called medically unexplained physical symptoms, the researchers said.

Sunlight could be primary benefit
Children and poor people suffered disproportionately from lack of green acres, the researchers found. The study findings were published online in the Journal of Epidemiology and Community Health.

Any number of factors could account for the benefits of green space, experts said. More natural sunlight, for instance, has been linked with a lower incidence of Seasonal Affective Disorder (SAD) and other benefits.

"If patients in hospitals have direct exposure to sunlight through a window or natural sunlight, hospital stays are shorter and patients have less complications," Rakel said. "That's been well-established.

More light also means more vitamin D in the skin, which has been found to elevate mood and improve muscle strength, he added. And fresh air, obviously, has a benefit as well, as do the exercise opportunities that come with more open space.

But much of the relief may come from the simple ability to de-stress.

Nature is ‘the way things were meant to be’
"If we're in a busy street with more technology and artificial things, we're going to be multi-tasking more, which prevents us from focusing on one thing," Rakel said.

"In this day and age, we really need some sort of centreing practice. We need to get our mind out of its own stories and focus on something that's pure. Nature is a beautiful example of that -- it's the way things were meant to be."

This study has "implications not only for city planning but also for indoor design and architecture," said Richard Ryan, professor of psychology, psychiatry and education at the University of Rochester Medical Centre. But the benefit is proportional to how much people pay attention to nature, he said.

"If they're in their heads and not paying attention, it doesn't do them much good," said Ryan, co-author of a recent study report that people who are exposed to natural elements are more socially oriented, more generous and value community more. Another experiment he was involved in found that people who spent time outdoors had more vitality and energy. – (EurekAlert, October 2009)