Life is stressful. With looming deadlines, 10-hour workdays and constantly buzzing smartphones, it's no wonder that a 2011 study by the American Psychological Association found that about seven out of 10 Americans report experiencing physical or non-physical symptoms of stress, including irritability, anger and fatigue.
And it turns out the age-old advice of taking a walk outside may actually be just what we need.
"Being in nature enhances wellbeing," says Roger Walsh, professor of psychiatry, philosophy and anthropology at the University of California at Irvine. Walsh is developing a PBS documentary about his project "8 Ways to Wellbeing" (8waystowellbeing.com), which focuses on how therapeutic lifestyle changes can prevent and treat psychological disorders while also enhancing wellbeing.
Contact with nature, he says, has a restorative effect on humans.
"Being in natural settings is intrinsically soothing and is shown to reduce unhealthy behavior," he says. "Exactly why isn't clear, but there is probably an evolutionary factor, as human beings and their predecessors were raised in, evolved in and likely designed for natural settings."
This affinity to natural life forms, what researchers term "biophilia," is now being incorporated into new therapy techniques such as walk-and-talk therapy and adventure-based counseling, according to clinical psychologist Mary Gregerson of Heartlandia Psychology in Parkville, Mo.
Being outdoors, she says, allows individuals an opportunity to "decompress" and can be a meditative experience. "You give yourself a change of pace and are able to lose a sense of that time pressure. It's about being in the moment. That in and of itself is the achievement that you're looking for."
While the positive effects of nature have been illustrated in numerous studies, researchers are just beginning to understand why and how this happens.
Marc Berman, assistant professor of psychology and cognitive neuroscience at the University of South Carolina, studies how interacting with nature can improve brain performance. He cites Stephen Kaplan's theory of attention restoration as a probable explanation for why we feel refreshed after spending time outdoors.
According to Kaplan, humans have two kinds of attention: directed attention, which requires controlled concentration and is both fatigable and can be depleted (such as completing a work task), and involuntary attention, which is automatic and not depleted (such as watching a river run).
Both types of attention are part of the human experience, says Berman, but our culture's high demand for directed attention leaves little time for involuntary attention. Being in a natural environment allows the brain to be stimulated, but in a more gentle way.
"It isn't all consuming. You can think about other things when you're looking at a river," says Berman, adding that researchers have found some similar kinds of mechanisms in this as they have in meditation.
This "soft" stimulation, as he deems it, has a restorative function and can actually increase brain performance. He tested the theory in his 2008 study "The Cognitive Benefits of Interacting with Nature," where his team recorded participants walking in both urban and natural environments. They found that a walk in the city, which requires a significant amount of directed attention with constant stimulation, did not provide the restorative benefits that a walk in the park did. After participants walked in the park, they experienced improvement in both memory and attention.
Berman also studied the groups walking in both warm and cold weather. While participants didn't take much pleasure in the winter walks, they still acquired all of the cognitive benefits. (Something to encourage getting out even in frigid temperatures.)
He's now trying to identify the mechanisms in nature that allow this restoration to occur, so that they can be incorporated into designs for important structures like hospitals and schools. "We're just scratching the surface," he says.
In the meantime, however, he points to the evidence that exposure to nature doesn't just seem to make someone feel good; it actually refreshes the mind -- and happens to be pretty easy to do.
"We weren't sending people to the Grand Canyon in these studies," he says, noting that the study participants walked through a local park. "It's so easily accessible."
This doesn't mean that life without any stress or stimulation is the ideal either. Gregerson, who specializes in methods of life coaching, cites the ancient Greek concept of the golden mean, which suggests that life is about a balance between two extremes.
"Allowing yourself to decompress, such as taking a brief walk through a park, can provide some balance to a particularly busy day," she says.