Whether an afternoon at the beach, an exhilarating weekend in the mountains or just a walk in the park after a hard day, millions of people around the world know how getting out into more natural surroundings makes you feel better.
But the health benefits of ‘connecting people to nature,’ the theme of this year’s World Environment Day, go deeper than that. They include global gains for mental health, disease control and the discovery of life-improving medicines for today and for future generations.
Mental health issues impose an enormous strain on societies. Depression alone affects 350 million people and is the leading cause of disability worldwide.
Connecting with nature can help ease that burden.
Researchers – some of them measuring brain waves and heart rates - have found that those of us who spend more time in green spaces have lower levels of stress, and fewer symptoms of depression and anxiety. Interacting with nature can also improve cognition for children with attention deficits and people with depression.
A 2014 study in the United Kingdom found that people who move to greener urban areas benefit from improvements in their mental health that can last for years. This is more evidence that creating more parks and gardens in cities improves public health.
In Japan, understanding of the health benefits of forests is so advanced that some local governments are promoting ‘forest therapy.’ Researchers there have found spending time in the woods can boost the immune system, including against cancer, as well as easing stress.
Likewise, South Korea has its official ‘healing forests’ and the health gains of time spent in nature are also gaining recognition in Finland.
Humans have spent most of their 2-3 million-year existence in natural environments. Our innate sense of well-being in nature is a phenomenon known as biophilia. Some fear it is being dangerously neglected in our increasingly urban and digital world.
A report from the National Trust, a UK conservation charity, says something must be done about ‘Nature Deficit Disorder’ a term to describe the human costs of alienation from nature. Those costs include: diminished use of the senses, attention difficulties, and higher rates of physical and emotional illnesses.
Though not a recognized medical condition, Nature Deficit Disorder captures how more and more children are “missing out on the pure joy of connection with the natural world; and as a result, as adults they lack an understanding of the importance of nature to human society.”
“If we do not reverse this trend towards a sedentary, indoor childhood – and soon – we risk storing up social, medical and environmental problems for the future,” the report argues.
Green spaces are also great places for sporting and recreational activities and so provide physical health benefits for many of us. Urban green spaces are key weapon in the fight against obesity: an estimated 3.2 million premature deaths in 2012 can be attributed to lack of physical activity.
Those of us fortunate enough to have a home with a garden can connect with nature by tending flowers and trees, and growing healthy fruit and vegetables free of harmful chemicals. Composting household and garden waste and using it as fertilizer provides another healthy connection with nature.
Respecting natural systems keeps us healthy in other critical ways.
Trees, for example, soak up carbon dioxide, shield us against traffic noise, and release oxygen into the atmosphere. Upland forests deliver clean water to towns and cities downstream.
More and more cities are planting trees to mitigate air pollution, which is the world’s largest single environmental risk to health: 7 million people across the world die each year due to everyday exposure to poor air quality.
Many of the world’s poorest people depend on forests not only for their health, but for their very survival. An estimated 1.6 billion people living in poverty use forests for all or part of their livelihoods.
Our connections with nature also include its provision of medicines, both traditional and modern.
The use of plants in traditional medicine dates back to the beginning of human civilization. Herbal medicine has clearly recognizable therapeutic effects and plays an important role in primary health care in many developing countries.
Common painkillers and anti-malarial treatments as well as drugs used to treat cancer, heart conditions and high blood pressure are derived from plants.
But even today, human beings are only beginning to discover the potential benefits of many species of trees and shrubs.
Trees from the Vernonia genus, for example, which chimpanzees regularly seek out when sick, have been found to contain chemical compounds that show promise in treating parasites such as pinworm, hookworm and giardia in humans.
Of course, every species that goes extinct means that its potentially valuable genetic riches go with it – perhaps putting important cures beyond our reach for ever.
For all these reasons, it pays to connect with nature and keep it healthy, because it is already returning the favour.