Most research on nature and human health has focused on pathology and natural disasters, but this preference by researchers has something to do with where the research funding comes from. Researchers looking at the health benefits of nature are, in fact, addressing a knowledge imbalance.
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The Nature Principle: Reconnecting with Life in a Virtual Age
by Richard Louv
The mind-body connection, of course, is a familiar concept, but research and common sense suggest a new container: the mind-body-nature connection.
Today, the long-held belief that nature has a direct positive impact on human health is making the transition from theory to evidence and from evidence to action. Certain findings have become so convincing that some mainstream health care providers and organizations have begun to promote nature therapy for an array of illnesses and for disease prevention. And many of us, without having a name for it, are using the nature tonic. We are, in essence, self-medicating with an inexpensive and unusually convenient drug substitute. Let’s call it vitamin N—for Nature.1
New research supports the contention that nature therapy helps control pain and negative stress, and for people with heart disease, dementia, and other health issues, the nature prescription has benefits that may go beyond the predictable results of outdoor exercise.2 The restorative power of the natural world can help us heal, even at a relative distance. On the surgical floors of a suburban, two-hundred-bed Pennsylvania hospital, some rooms face a stand of deciduous trees, while others face a brown brick wall. Researchers found that compared to patients with brick views, patients in rooms with tree views had shorter hospitalizations (on average, by almost one full day), less need for pain medications, and fewer negative comments in the nurses’ notes.3 In another study, patients undergoing bronchoscopy (a procedure that involves inserting a fiber-optic tube into the lungs) were randomly assigned to receive either sedation or sedation plus nature contact—in this case, a mural of a mountain stream in a spring meadow and a continuous tape of complementary nature sounds (e.g., water in a stream or birds chirping). The patients with nature contact had substantially better pain control.4
Nearby nature can be an antidote to obesity. A 2008 study published in American Journal of Preventive Medicine found that the greener the neighborhood, the lower the body mass index of children. “Our new study of over 3,800 inner-city children revealed that living in areas with green space has a long-term positive impact on children’s weight and thus health,” according to senior author Gilbert C. Liu, MD. While the investigation didn’t prove a direct cause and effect, it did control for many variables, including the neighborhood’s population density. The results support those who believe that changing the built environment for inner-city kids is just as important as attempts to change family behavior.5
A study of 260 people in twenty-four sites across Japan found that among people who gazed on forest scenery for twenty minutes, the average concentration of salivary cortisol, a stress hormone, was 13.4 percent lower than that of people in urban settings.6 “Humans . . . lived in nature for 5 million years. We were made to fit a natural environment. . . . When we are exposed to nature, our bodies go back to how they should be,” explained Yoshifumi Miyazaki, who conducted the study that reported the salivary cortisol connection. Miyazaki is director of the Center for Environment Health and Field Sciences at Chiba University and Japan’s leading scholar on “forest medicine,” an accepted health care concept in Japan, where it is sometimes called “forest bathing.” In other research, Li Qing, a senior assistant professor of forest medicine at Nippon Medical School in Tokyo, found green exercise—physical movement in a natural setting—can increase the activity of natural killer (NK) cells. This effect can be maintained for as long as thirty days.7 “When NK activity increases, immune strength is enhanced, which boosts resistance against stress,” according to Li, who attributes the increase in NK activity partly to inhaling air containing phytoncides, antimicrobial essential wood oils given off by plants. Studies of this sort deserve closer scrutiny. For example, in the study of natural killer cells, there was no control group, so it is hard to say if the change was due to time off work, exercise, nature contact, or some combination of influences.
Ghosts of Nature Past
From the backyard to the backcountry, nature comes in many forms. The negative impacts of the risks that do occur in wilderness (from large predators, for example) should be balanced by the positive psychological benefits of that risk (humility, for one). And, yes, most research on nature and human health has focused on pathology and natural disasters, but this preference by researchers has something to do with where the research funding comes from. Researchers looking at the health benefits of nature are, in fact, addressing a knowledge imbalance.
A few years ago, I worked with a council of neuroscientists, experts on the childhood development of brain architecture. When asked how the natural world itself affects brain development, they would usually draw a blank. “How do you define nature?” they asked, rhetorically. However, these same scientists simulate “natural conditions” in their labs for control groups. A friend of mine likes to say that nature is anything molecular, “including a guy drinking beer in a trailer park and a debutante drinking highballs in Manhattan.” Technically, he’s right. For the most part, we’ve left the definition of nature up to philosophers and poets. Gary Snyder, one of our finest contemporary poets, has written that we attach two meanings to the word, which comes from the Latin roots natura and nasci, both of which suggest birth.
Here’s my definition of nature: human beings exist in nature anywhere they experience meaningful kinship with other species. By this description, a natural environment may be found in the wilderness or in a city; while not required to be pristine, this nature is influenced at least as much by a modicum of wildness and weather as by developers, scientists, beer drinkers, or debutantes. We know this nature when we see it.
And centuries of human experience do suggest that the tonic is more than a placebo. How then, when it comes to health, does the nature prescription work?
The answers may be hidden in our mitochondria. As hypothesized by Harvard’s E. O. Wilson, biophilia is our “innately emotional affiliation to . . . other living organisms.”8 His interpreters extended that definition to include natural landscape. Several decades of research inspired by Wilson’s theory suggests that at a level we do not fully understand, the human organism needs direct experience with nature.
Gordon H. Orians, a renowned ornithologist, behavioral ecologist, and professor emeritus in the Department of Biology at the University of Washington, maintains that our attraction to the natural environment exists at the level of our DNA, and, in its many genetic forms, haunts us. He points out that between the first appearance of agriculture and this morning’s breakfast, only about ten thousand years have elapsed. “The biological world, like the mental world of Ebenezer Scrooge, is replete with ghosts,” he says. “There are ghosts of habitats, predators, parasites, competitors, mutualists, and conspecifics past, as well as ghosts of meteors, volcanic eruptions, hurricanes, and droughts past.”9 These ghosts may reside in our genetic attic, but sometimes they speak to us, whispering the past is prologue.
This view, based on behavioral ecology or sociobiology, has its critics, who are suspicious that such thinking evokes genetic predeterminism. In recent years, though, the proponents of biophilia and its doubters appear to have come to something approaching agreement: long-term genetics may lay down a likely pathway for brain development, but the outcome is also determined by the more current environment—by attachment to nurturing human beings, for example. Orians argues that all adaptations are to past environments. “They tell us about the past, not the present or the future. . . As Ebenezer Scrooge discovered, ghosts, no matter how inconvenient they may seem to be, can yield positive benefits.” He adds: “People have clearly intuitively understood the restorative value of interactions with nature for a long time.” Witness the gardens of ancient Egypt, the walled gardens of Mesopotamia, the gardens of merchants in medieval Chinese cities, the American parks of Frederick Law Olmsted, or even the choices we make when picking sites for our homes and our visual responsiveness to certain landscapes. Orians and Judith Heerwagen, a Seattle-based environmental psychologist, spent years surveying people around the world, testing their preference for different images. The researchers found that regardless of culture, people gravitate to images of nature, especially the savanna, with its clusters of trees, horizontal canopies, distant views, flowers, water, and changing elevations.
Another explorer of human biophilic tendencies, Roger S. Ulrich, professor of landscape architecture and urban planning at Texas A&M University, proposed his psychophysiological stress recovery theory in 1983, suggesting that our responses to stress are located in the limbic system, which generates survival reflexes. Citing Ulrich, physician William Bird, an honorary professor at Oxford University and chief health adviser for Natural England, the British government’s environmental arm, explains: “The fight-or-flight reflex is a normal response to stress caused by the release of catecholamines (including adrenaline) and results in muscle tension, raised blood pressure, faster pulse, diversion of blood away from the skin to muscle, and sweating. All of these factors help the body to cope with a dangerous situation. However, without rapid recovery, this stress response would cause damage and exhaustion with limited response to a repeat dangerous situation.”10 Evolution favored our distant ancestors who could recover from the stress of natural threats by using the restorative powers of nature.
One of the best explanations I have heard for this process came from the late Elaine Brooks, a California educator who worked for years as a biologist at the Scripps Institution of Oceanography. In Last Child in the Woods, I described how Brooks would often climb to the highest knoll in the last natural open space of La Jolla. She told me how, particularly in times of personal stress, she would imagine herself as her own distant ancestor, high in a tree, recovering from the threat of some predator. At those times, she would look out over the rooftops—which she would imagine to be the open plains of a savanna—to the sea. She would feel her breath slow and her heart ease. “Once our ancestors climbed high in that tree, there was something about looking out over the land—something that healed us quickly. Resting in those high branches may have provided a rapid comedown from the adrenaline rush of being potential prey,” she told me one day, as we walked that land. “We are still programmed to fight or flee large animals. Genetically, we are essentially the same creatures as we were at the beginning. Our ancestors couldn’t outrun a lion, but we did have wits. We knew how to kill, yes, but we also knew how to run and climb—and how to use the environment to recover our wits.”
She went on to describe modern life: how today we find ourselves continually on the alert, chased, as she put it, by an unending stampede of two-thousand-pound automobiles and four-thousand-pound SUVs. Inside our workplaces and homes, the assault continues: threatening images charge through the television cable into our bedrooms. Probably, at the cellular level, we have inherited the efficient antidote to all of this: sitting on that knoll, as Brooks did.
From The Nature Principle, by Richard Louv. © 2011, 2012 by Richard Louv. Reprinted by permission of Algonquin Books of Chapel Hill. All rights reserved.
1. In the United States, Glamour magazine offers a blog called Vitamin G, for Green. European public health officials also refer to vitamin G. For researchers in the Netherlands, the G stands for green, specifically the effect of green space on health and learning and feelings of social safety. The current, and still champion, definition of vitamin G is riboflavin (also known as B2). Vitamin N may be a bit problematic, as in some street parlance the N refers to nicotine. Others have referred to vitamin N, as in nature, including Linda Buzzell--Saltzman, founder of the International Association for Ecotherapy, in a 2010 blog for Huffington Post, as has Valerie Reiss in Holistic Living in 2009.
2.. M. Wichrowski, J. Whiteson, F. Haas, A. Mola, and M. J. Rey, “Effects of Horticultural Therapy on Mood and Heart Rate in Patients Participating in an Inpatient Cardiopulmonary Rehabilitation Program,” Journal of Cardiopulmonary Rehabilitation 25, no. 5 (2005): 270–74. Also see C. M. Gigliotti, S. E. Jarrott, and J. Yorgason, “Harvesting Health: Effects of Three Types of Horticultural Therapy Activities for Persons with Dementia,” Dementia: The International Journal of Social Research and Practice 3, no. 2 (2004): 161–80. Finally, see Gene Rothert, “Using Plants for Human Health and Well--Being,” Palestra, Winter 2007, findarticles.com/p/articles/mi_hb6643/is_1_23/ai_n29335131/.
3. See R. S. Ulrich and R. F. Simons, “Recovery from Stress During Exposure to Everyday Outdoor Environments,” in Proceedings of the Seventeenth Annual Meetings of the Environmental Design Research Association (Washington, DC: EDRA, 1986): 115–22; J. A. Wise and E. Rosenberg, “The Effects of Interior Treatments on Performance Stress in Three Types of Mental Tasks,” CIFR Technical Report No. 002–02 (1988), Ground Valley State University, Grand Rapids, MI; R. S. Ulrich, “View through a Window May Influence Recovery from Surgery,” Science 224 (1984): 420–21.
4. G. Diette, M. Jenckes, N. Lechtzin, et al., “Predictors of Pain Control in Patients Undergoing Flexible Bronchoscopy,” American Journal of Respiratory and Critical Care Medicine 162, no. 2 (2000): 440–45, ajrccm.atsjournals.org/cgi/content/abstract/162/2/440; Gregory B. Diette, Noah Lechtzin, Edward Haponik, Aline Devrotes, and Haya R. Rubin, “Distraction Therapy with Nature Sights and Sounds Reduces Pain During Flexible Bronchosopy,” Chest 123, no. 3 (2003): 941–48, chestjournal.chestpubs.org/content/123/3/941.full.
5. J. F. Bell, J. S. Wilson, and G. C. Liu, “Neighborhood Greenness and Two-Year Changes in Children’s Body Mass Index,” American Journal of Preventive Medicine 35, no. 6 (2008): 547–53.
6. B. J. Park, Y. Tsunetsugu, T. Kasetani, T. Kagawa, and Y. Miyazaki, “The Physiological Effects of Shinrin-yoku (Taking in the Forest Atmosphere or Forest Bathing): Evidence from Field Experiments in Twenty-four Forests across Japan,” Environmental Health and Preventive Medicine 15, no. 1 (2010): 18–26.
7. Q. Li, K. Morimoto, A. Nakadai, et al., “Forest Bathing Enhances Human Natural Killer Activity and Expression of Anti-Cancer Proteins,” International Journal of Immunopathology and Pharmacology 20 (2007): 3–8.
8. In Peter H. Kahn’s book Technological Nature: Adaptation and the Future of Human Life (Cambridge, MA: MIT Press, 2011), Kahn offers a brief history of the term biophilia: “This term was used as early as the 1960s by [Erich] Fromm . . . in his theory of psychopathology to describe a healthy, normal functioning individual, one who was attracted to life (human and nonhuman) as opposed to death. In the 1980s, [E. O.] Wilson . . . published a book titled Biophilia. I have never seen Wilson cite Fromm’s use of the term, so it is unclear whether Wilson was aware of this earlier usage. Either way, Wilson shaped the term from the perspective of an evolutionary biologist. He defined biophilia as an innate human tendency to affiliate with life and lifelike processes. Biophilia, according to Wilson, emerges in our cognition, emotions, art, and ethics, and unfolds ‘in the predictable fantasies and responses of individuals from early childhood onward. It cascades into repetitive patterns of culture across most of all societies.’ ” See Edward O. Wilson, Biophilia: The Human Bond with Other Species (Cambridge, MA: Harvard University Press, 1984), 85. Also see Stephen Kellert and Edward O. Wilson, eds., The Biophilia Hypothesis (Washington, DC: Island Press, 1993), 31.
9. Gordon H. Orians, “Metaphors, Models, and Modularity,” Politics and Culture, April 29, 2010, www.politicsandculture.org/2010/04/29/metaphors--models--and--modularity/.
10. William Bird, “Natural Thinking—Investigating the Links between the Natural Environment, Biodiversity, and Mental Health,” A Report for the Royal Society for the Protection of Birds (June 2007): 40; www.rspb.org.uk/Images/naturalthinking_tcm9-161856.pdf.