YouAbout twenty-six children, their parents, and others gathered under redwoods near Oakland in April 2022. They sat with a physician, Dr. Nooshin Razani, beneath the branches of the ancient giants, breathing the fresh air and discussing the phenomenon of fairy rings—when a mama tree is cut down, the baby trees grow up in a circle surrounding the stump of the parent tree.
These families are taking part in a program Razani runs at the University of California San Francisco Benioff Children’s Hospital Oakland. The program, called the Center for Nature and Health, takes pediatric patients who are dealing with conditions like anxiety, autism, obesity, or developmental issues—and who live in areas without much nature nearby—into local parks on excursions with park staff each month.
The program is part of a growing trend of so-called “park prescriptions,” which have increased in popularity over the last decade along with research into the health effects of spending time in nature. Physicians strongly recommend that patients of all ages spend more time outdoors to improve their mental as well as physical health.
“It’s pretty clear that it’s good for you,” says Razani. Studies show that being near nature and taking part in outdoor recreation can have a positive impact on mental health as well as reducing the risk of developing certain health problems like heart disease. Scientists are still trying to figure out why, but the leading theory is that spending time in nature reduces stress, a state that’s tied to many health problems.
However, doctors are not advising their patients to visit the park rather than prescribing anti-anxiety drugs. Nature is not a cure for health issues—and park prescriptions aren’t meant to be used instead of prescriptions for medications. However, people can reap the real benefits of their local nature.
Park prescriptions: A historical overview
Although there are many different types of nature prescriptions available, they all allow doctors and other health professionals to encourage their patients’ to enjoy the outdoors. Walk with a Doc is a program that encourages health professionals to take walks in the community. It was started in 2005 by a cardiologist. The walk has now expanded to over 500 locations around the globe.
ParkRx was the U.S.’s first park-prescription program when it began in 2013. It provides guides, case studies, and toolkits to aid health professionals in getting their patients outside. PaRx Canada was launched officially in 2020. PaRx provides ample evidence about the benefits of nature for health and information for doctors. PaRx also created a virtual nature prescription that doctors can include in a patient’s electronic health record. The program is used by more than 5,000 healthcare professionals.
The practice of nature prescribing also has popularity overseas. In collaboration with the Royal Society for the Protection of Birds Scotland (RSPBS), doctors in Scotland began writing nature prescriptions for their patients in 2017. The NHS created a network of referrals to help patients connect with nature-based activities such as walking or community gardening, during the influenza pandemic.
The natural way nature can improve your health
Everyone’s health could benefit from a closer connection to nature. Not everyone can have equal access to nature. The green spaces in wealthier areas tend to be more extensive than those in poorer communities. That’s partly why Razani’s program focuses on children who do not have adequate green space close to home. These are often the people who most need nature’s healing powers. “The end condition the clinician is seeing may vary, from obesity and anxiety,” she says, but two important upstream reasons for these conditions are “stress and lack of access to outdoor space.”
Mat White is a University of Vienna health psychologist. He says that physiological changes occur when the body experiences stress. Stress triggers cortisol release, which can lead to an increase in blood pressure and heart beat. He notes that anxiety and depression are linked to chronically high levels of stress. Studies have shown that stress can also be linked to obesity and heart disease.
Researchers believe that positive encounters in nature may help reduce stress and cognitive fatigue. “The major theories in the field currently coalesce around the idea of stress reduction,” White says.
According to experts, these theories stem from research that gained momentum in 2010. Numerous studies show a correlation between nature-based activities and better mental and physical health. “We know there’s a robust relationship between mental health and nature exposure,” says Matthew Browning, founding director of the Virtual Reality and Nature Lab at Clemson University who studies the link between the natural world and human health. There’s also a relationship between long-term exposure to nature and reduced risk of cardiovascular disease and death from any cause, he says. The 2008 publication of a major, early research in this field in the LancetThe study found that those who lived in more green areas in England were less likely to die from cardiovascular diseases or any other cause. “Physical environments which promote good health may be important in the fight to reduce socioeconomic health inequalities,” the authors wrote in the study.
Browning says that people who live in more green areas tend to pay less for health care. The study is published in the May 2022 issue. Environment International, Browning and his colleagues examined the total health-care costs of 5 million people in Northern California over a decade and compared those costs with the amount of green space or trees around each person’s home, determined through satellite data. The correlation between living in greener areas and lower healthcare costs was strong regardless of any other factors such as income and occupation.
Gregory Bratman is the director of the University of Washington’s environment and well-being laboratory. He says there are two major theories about how nature exposure can help our stressed brains. One theory, called the Stress Reduction Theory in scientific circles is that natural forms can engage the parasympathetic nervous systems, responsible for relaxation, digestion, and stress recovery. (It’s nicknamed the “rest and digest” system.) The other, the Attention Restoration Theory, suggests that nature engages people’s “soft fascination,” says Bratman. Bratman says this allows our “directed attention”, which is what we focus on, to rest and replenish.
Much of the research has focused just on the visual aspects of nature—seeing the green of trees or grass, or the blue of a river or ocean. But “nature experiences are multi-sensory,” notes Bratman. Practitioners shinrin-yoku (or “forest bathing”) in Japan theorize that the scent and experience of breathing in the compounds that trees exude into the air could impact immune function, says Bratman. Sound is another key sense that may indicate safety or danger, allowing relaxation or exacerbating stress—and soothing nature sounds fit firmly in the first camp, says Rachel Buxton, a conservation scientist at Carleton University in Canada, who studies soundscapes, seabird ecology, and ecological restoration.
Scientists still don’t know everything about how nature affects health. Many of the studies that find a relationship between the two just look at trends in the general population—not within specific groups, like people with anxiety or depression, says White. It would require ethically complicated experiments on small populations of patients to determine the direct impact of nature’s actions on particular conditions, White says. Because of these complications, scientists don’t have much high-quality evidence as to how nature could affect those people who, theoretically, are in most need of a park prescription.
It’s also possible that pressuring someone to spend more time in nature might reduce some of the benefits of the visit, says White. White and colleagues published a 2020 study that found social pressure to go outside was linked to a greater likelihood of getting outdoors, as well as lower motivation and happiness, higher anxiety, and less enjoyment during the trip. As soon as you tell someone to do something, “there’s a chance it undermines people’s intrinsic enjoyment,” says White.
There are still many questions that need to be answered about optimizing a nature-prescribed time. “We don’t really know how much time people need to spend in nature, [or] what types of nature,” says Browning. Research is still unclear about what the significance of exposure to nature is. Is a manicured park with turf grass and a ballfield enough, or do people benefit more when they go out in the woods—somewhere rich in biodiversity? What’s more, the type of nature someone finds relaxing could be highly individual, based perhaps on their familiarity with a particular landscape, says Browning.
These knowledge gaps are being filled by scientists. Razani recently was awarded a $1.2million grant to investigate the impact of her natural intervention on anxiety among children. Ulrika Stigsdotter is a professor of planning and landscape architecture at the University of Copenhagen, Denmark. She focuses her research on outdoor health design that uses evidence.
Stigsdotter says that some of the research focuses on how outdoor spaces could be made more suitable for nature therapy. It is important to consider the environment if you want to find nature-based treatment options that can improve patients’ health, such as those suffering from depression and anxiety. She says that the setting of a garden, or any other landscape should be appropriate for who it will be used. Someone suffering from cancer might respond differently to certain designs than someone who is depressed or who has just moved into a retirement home. “The treatment program depends on the context,” she says.
In the general population, it’s also important not to overstate the effects of nature, says White. “These effects of green and blue space are small” for most people, says White, particularly compared to other factors that affect our health like relationships, job satisfaction, and financial stability. “They’re marginal effects, but they apply to millions of people. So the overall public health benefit is huge, but small for any given individual.”
These health benefits can be harnessed across whole populations. This will require expanding access. A prescription to get outside can’t address the issues surrounding access to green space. It can’t expand green space in neighborhoods that lack them, or guarantee that vulnerable people feel comfortable going to these green spaces, or combat all the stress and illness people face.
“If we had healthy ecosystems [available to] all income levels, we wouldn’t need to take excursions into nature,” says Razani.
Razani is still able to see the effectiveness of her program. She’s seen a little boy with developmental issues come alive learning about trees, impressing the park naturalist with his deep knowledge. She’s watched another child with autism and anxiety became calm, engaged, and confident while exploring a regional park. She says that the adults who participate in this program also experience transformation. A mother who survived domestic abuse brought her children and became a leader in nature for others.
The more researchers learn about the stress-reducing powers of nature, “what public health people have always been saying—that health starts outside the clinic—is just becoming more and more apparent,” says Razani.
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