The Best Natural Medicine? Nature Itself

According to Tierney Thys of National Geographic, “As of 2010, we have officially become an urban species. More of us live in cities than don’t, and that is a trend that is continuing and accelerating … The average North American and European spends 90 percent of their time indoors.” Thys suggests that all sorts of modern maladies are an indirect result of spending too much time indoors — these illnesses range from myopia, obesity, diabetes, cardiovascular disease, behavioral disorders, and depression.

Indeed, living in a concrete jungle is associated with “a 21 percent increased risk of anxiety disorders and a 39 percent increased risk of mood disorders. In addition, the incidence of schizophrenia is twice as high in those born and brought up in cities.” Recent brain imaging studies support this finding. A study conducted by Andreas Meyer-Lindenberg of the University of Heidelberg put participants in stressful situations that involved “difficult mental arithmetic tasks.” Brain scans showed that, “The amygdala of participants who currently live in cities was overactive during stressful situations.” The amygdala is largely responsible for the body’s fear-response and “is therefore linked to anxiety and depression.” Moreover, the cingulate cortex was more active in city dwellers; this region is “important for controlling emotion and dealing with environmental adversity.”

The researchers conjecture that the increased firing in these two brain regions may be the reason for higher rates of mental illness in those who live in cities. Meyer-Lindenberg explains, “We speculate that stress might cause these abnormalities in the first place — that speculation lies outside what we can show in our study, it is primarily based on the fact that this specific brain area is very sensitive to developmental stress. If you stress an animal, you will find even structural abnormalities in that area and those may be enduring and make an animal anxious. What we’re proposing is that stress causes these things and stress is where they are expressed, and then lead to an increased risk of mental illness.”

Though not necessarily related to living in urban settings, another issue that arises from too much time indoors is unprecedented exposure to screens — that is, of the television, computer, and smartphone variety. Dr. Victoria L. Dunckley, a pediatric psychiatrist, expresses concerns about the finding that “the average child clocks in more than seven hours [of screen time] a day.” She explains, “As a practitioner, I observe that many of the children I see suffer from sensory overload, lack of restorative sleep, and a hyperaroused nervous system, regardless of diagnosis — what I call ‘electronic screen syndrome.’ These children are impulsive, moody, and can’t pay attention …”

Ultimately, living in urban settings, staring at electronic screens, and just generally spending the bulk of one’s existence inside four cinderblock walls — all of these experiences are united by a deficiency. They all result in a lack of exposure to the natural world. The restoration of this shortage — which some deem “nature deficit disorder” — is a crucial component to optimal human health. Therefore researchers have been exploring what cognitive benefits are ostensibly conferred by exposure to the natural world.

Much of the current research on this subject involves a concept known as “attention restoration theory.” Introduced by Stephen Kaplan and his colleagues in the 1980s and ’90s, this theory asserts that, “Nature has the capacity to renew attention after exerting mental energy …” In his 1995 paper “The Restorative Benefits of Nature,” he evaluates a number of studies that consistently linked nature and improved directed attention, “despite wide variation in setting and procedure.” In essence, this theory suggests that the demands of our daily lives require prolonged focus, which ultimately compromises our mental faculties. The experience of being in nature, “does not require focus and involves effortless reflection … [This enables] the directed attention system to recover from depletion.”

This notion is supported by a growing bounty of research, including a study published in the Journal of Environmental Psychology. The study’s authors hypothesized that, “Microbreaks spent viewing a city scene with a flowering meadow green roof would boost sustained attention.” Indeed, the participants who viewed a green roof for only 40 seconds between two cognitive tests performed significantly better than those who viewed a concrete rooftop. The authors infer that, “This reflects boosts to subcortical arousal and cortical attention control.”

These benefits appear to affect individuals across the lifespan. In kids, researchers have measured cognitive development in primary schoolchildren as a “12[-month] change in developmental trajectory of working memory, superior working memory, and inattentiveness.” The results “showed a beneficial association between exposure to green space and cognitive development among schoolchildren that was partly mediated by reduction in exposure to air pollution.” Furthermore, time spent in nature seems to reflect positively on children diagnosed with attention deficit hyperactivity disorder. Dr. Frances E. Kuo explains the study’s findings: “Green outdoor activities reduced symptoms significantly more than did activities conducted in other settings, even when activities were matched across settings. Findings were consistent across age, gender, and income groups; community types; geographic regions; and diagnoses.”

Likewise, elderly individuals are not exempt from nature’s purported benefits. A study in the Journal of Aging Health shows that getting outside on a daily basis may help older people stay healthy and functioning longer. Participants in the study who spent time outdoors every day at age 70 showed fewer complaints of aching bones or sleep problems, among other health-related problems, at age 77 than those who did not head outside each day.”

These positive prognoses also seem to extend to one’s physical health. A study by Roger S. Ulrich investigated how the view from one’s hospital room — either of green trees or of brick buildings — affected the ease and speed of recovery following gallbladder surgery. Ulrich “was struck by how much better the patients fared when their rooms looked out onto the trees rather than the brick wall. On average, those who faced the brick wall needed an extra day to recover before returning home. They were also far more depressed and experienced more pain … By some measures, patients who gazed out at a natural scene were four times better off than those who faced a wall.”

As such, we can reasonably assume that being in — or even just looking at — nature generally comes with cognitive and physiological rewards, from improved focus to superior childhood development, as well as increased longevity and better physical recovery.

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