Nature's positive effects on well-being

Contact with nature, whether at untouched wilderness or a backyard tree, alleviates stress and improves health

A 

Throughout history, nature has been associated with improving people's health and well-being, and some have been designated for this purpose. Cyrus the Great, the successful Persian Emperor, built gardens for relaxation in the busy capital of Persepolis some 2 500 years ago. The 16th-century German-Swiss physician, Paracelsus, wrote, 'The art of healing comes from nature, not from the physician.' Later, in 1865, the great landscape architect Frederick Law Olmsted had already designed Central Park in New York City; he was convinced that beautiful green spaces should exist for all people to enjoy. As well as creating the world's first national parks, he claimed that nature had healing powers. There wasn't much scientific evidence then for these powers but there is now with the advancement of epidemiological, psychological and brain-based research.

B 

David Strayer is a cognitive psychologist at the University of Utah who specialises in the human capacity to maintain attention. One area of his research in the US has shown that using a cell phone impairs our brain as much as drinking alcohol does. Human brains are prone to mistakes, especially when multitasking. Strayer is in a unique position to understand what modern life does to us and has researched how camping trips in nature can be used as an antidote. Strayer has demonstrated a phenomenon he calls the 'three-day effect', in which subjects after three days of walking and backpacking through the wilderness. He explains that brains are easily fatigued, when we slow down, stop the busy work, and take in beautiful natural surroundings, not only do we feel physically refreshed, but our mental performance improves too. Strayer has found support for his hypothesis that being in nature allows the prefrontal cortex, the brain's command centre, to dial down and rest, like an over-used muscle.

C 

In England, researchers from the University of Exeter Medical School recently analysed mental health data from 10 000 city dwellers over a period of 18 years and used high-resolution mapping to track where the subjects had lived. They found that people living near more green space reported less mental distress, even after adjusting for income, education, and employment (all of which are also correlated with health). In 2009 a team of Dutch researchers found a lower incidence of 15 diseases — including depression, anxiety, heart disease, diabetes, asthma, and migraines — in people who lived within about a half-mile of green space. Lower mortality and fewer stress hormones circulating in the blood have also been connected to living close to green space. Richard Mitchell, an epidemiologist at the University of Glasgow in Scotland, carried out a large study and found less disease in people who lived near parks or other green space — even if they didn't use these green spaces. This was particularly true amongst people with lower incomes.

D 

Mitchell and other researchers theorize that nature works primarily by lowering stress. Compared to people without window views, those who can see trees and grass have been shown to recover faster in hospitals, perform better in school, and even display less violent behaviour. Such results are in accordance with experimental studies of the central nervous system and brain-wave patterns. Measurements of stress hormones, respiration, heart rate, and sweating suggest that short doses of nature — or even pictures of the natural world — can calm people down and sharpen their performance. For example, in Sweden, physician Matilda van den Bosch found that after a stressful math test, subjects' heart rate variability — which decreases with stress — returned to normal more quickly when they sat through 15 minutes of nature scenes and birdsong in a 3-D virtual-reality room than when in a plain room.

E 

A 15-minute stroll in the woods has been shown to cause measurable changes in physiology. Japanese researchers led by Yoshifumi Miyazaki at Chiba University sent 84 subjects to stroll in seven different forests, while the same number of volunteers walked around city centres. Overall the forest walkers showed a 16 percent decrease in the stress-hormone cortisol, a 2 percent drop in blood pressure, and a 4 percent drop in heart rate. These results were not mirrored in the other group. Miyazaki believes our bodies and brains relax in pleasant, natural surroundings because our senses have evolved to interpret information about plants and streams, not traffic and high-rise buildings.

F 

In some countries, governments are promoting nature experiences as a public-health policy. Professor Liisa Tyrväinen and her team at the Natural Resources Institute Finland recommend a minimum nature dose of five hours a month — several short visits to the countryside — to prevent mental illness. 'A 40- to 50-minute walk seems to be enough for physiological changes and mood changes and probably for attention,' says Kalevi Korpela, a professor of psychology at the University of Tampere, Finland.

G 

Perhaps no nation has embraced the medicalization of nature with more enthusiasm than the South Koreans. Many suffer from work stress and intense academic pressures. More than 70 percent say their jobs, which require notoriously long hours, cause depression, according to a survey by electronics giant Samsung. Forest minister, Shin Won Sop is a social scientist who has studied the positive effects of forest therapy. Official healing forests, where people relax in nature, are now popular in South Korea and many more are planned so that people in nearly all major towns will be close to one. In these healing forests, school children can take part in forest meditations, walking tours, woodcrafts, and many more. Shin has data suggesting that forest healing reduces medical costs and benefits local economies. Time will tell if other countries will follow suit.