Nature’s effect on human biology

“The woods were my Ritalin. Nature calmed me, focused me, and yet excited my senses”     -Richard Louv

     Today, many people spend entire workdays under fluorescent lights hunched in front of their computers, only to come home and bask in the glow of their television screens. In 2018 the Environmental Protection Agency surveyed 9,000 Americans and discovered that they were spending around 89 percent of their time indoors (Premier). In the last 20 years, there has been a nearly 10% increase in cases of ADHD (Bluth). In addition, nearly 50% of college students nationwide attended counseling for mental health concerns during the 2012-2013 school year (Heiser). Research has provided substantial evidence that the increasing rates of some mental and physical conditions is directly linked to the decreasing amount of time we spend outside.

     In today’s world, many people of all ages suffer from attention disorders, stress, anxiety, and depression. Studies have shown that while it may not eliminate the issue entirely, even just five minutes of time outside can have a positive impact. In addition to helping mental health, nature has been shown to help reduce cholesterol levels, improve sleep cycles, reduce heart rate, and lower blood pressure, as well as even helping patients with type II diabetes (Yar).

     With all this said, it’s not particularly surprising that more outdoor time is also better for students. It has been shown to improve both mental and physical health, in addition to their ability to learn. Through detailed studies, we are constantly trying to identify what strategies are most effective to enhance learning and our ability to attain new information. We have found that different methods of learning suit different minds. However, across the board, it’s learning outside the classroom that seems to have the longest lasting effects (Bangkok).

     As quoted in The New York Times article by Tara Parker-Pope, a small study was conducted at the University of Illinois to look at how the environment influences a child’s concentration skills. The researchers evaluated 17 children with attention deficit hyperactive disorder. Each child was given a baseline test called Digit Span that tests one’s ability to concentrate. The test is specially designed so that no matter how much one practices it is impossible to improve one’s score.

     Each child was taken on three walks, in a park, a residential neighborhood, and a downtown city area. After each walk, the children were given another Digit Span test. The walks were taken in varied orders and the researchers administering the tests were unaware of which walk each child had just completed.

     The University of Illinois study was published online in the Journal of Attention Disorders. It found that children were able to focus much better after the “green” walks compared to the walks in other settings (Pope). Although the study was small, data from many other sources support this conclusion. In 2004 a survey of 450 parents found that “green” outdoor activities significantly reduced ADHD symptoms and allowed their child to focus on schoolwork (qtd. in Pope). Similar studies have even found that a “dose of nature” worked as well or better than a dose of medication on the child’s ability to concentrate (Pope). While it might not last as long as a dose of medication, nature is free and accessible to everyone.

     Time outdoors isn’t only beneficial to young students, it is equally important to people of all ages. A study conducted at Stanford University has shown that simply looking at nature for short periods of time significantly increases the brain’s ability to pay attention. In addition, exposure to sunshine increases levels of vitamin D, which improves muscle function, the immune system, and mood (Heiser). Nature is a free and easy way to reduce stress that many students do not take nearly enough advantage of.

     In addition to students, increased outdoor time means more time outside for teachers. Time in nature could help improve teachers’ moods and even their ability to manage their students effectively, providing yet another clear example of the benefits of outdoor learning (Bishop).

     In Audubon medal recipient Richard Louv’s book “Last Child in the Woods,” he lumps all of these things like ADHD and depression into one overarching category termed “Nature Deficit Disorder.” The phrase describes the “human cost of alienation from nature” (Louv 36). Among the effects of nature deficit disorder, he describes diminished use of the senses, attention difficulties and higher rates of physical and emotional illnesses (Louv 36).

     There is no doubt that at least to some degree, nature is good for us. However, it’s not exactly practical for everyone to live in non-urban areas. By the year 2050, nearly 70 percent of the global population is projected to be living in urban areas (Yar). So besides making time to get out of the city, what can people do? Inspired by a notable study in 2008, a more recent study found that the attention span of both adults and college-aged students visibly improved after being exposed to even just photos of nature (Yar). In our modern day lives, many of us spend so much of our time indoors. So even just putting up photos in our workplace, home, or classroom can substantially benefit our emotional and physical health.

     For someone experiencing depression, “green” time can be one of the best medications. In 2017 a team from Stanford University found that students who walked for 90 minutes in a green park versus strolling next to a loud highway exhibited “quieter brains.” Based on follow up brain scans and questionnaires after the “green” walk, subjects seemed to dwell less on the negative aspects of their lives. Brain scans also recorded significantly less activity in the prefrontal cortex, an area of the brain associated with depression (qtd. in Yar).

     In addition to affecting neurotransmitters like serotonin and endorphins, which help us relax, being outdoors exposes us to natural light, which in turn caused the melatonin levels in our bodies to decrease. This helps us to wake up in the morning and feel more alive throughout the day. In the absence of sunlight, our bodies produce more melatonin, causing us to feel sleepy or lethargic. So getting sunlight at the right times of day can lead to healthier sleep cycles and in turn, getting a better night’s sleep (Premier).

     How nature does all this still isn’t entirely understood. Research has conclusively shown that seeing images of lush green nature can cause our brains to relax, our neurotransmitters to normalize, and even normalize our sleep cycles. However, we still can’t entirely explain why. This idea of nature affecting the brain is a hot topic among evolutionary psychologists and is a rapidly expanding field in science. As of 2017, the subject was assigned the name “Neurobiophilia.” The name refers to the study of, “how nature affects the brain” (Thys).

     As can be seen in so many examples, mental and physical health are closely interwoven. A 2010 study found that participants who walked in a forest had lower blood pressure and levels of cortisol, the hormone associated with stress. In addition to the many genetically embedded benefits we receive from nature like lowered cholesterol levels, blood pressure, and even heart rates, there are also many external side effects. As quoted in the NBC article by Christina Heiser, Jay Lee, MD states, “you’re also less likely to catch a virus, since you’re not breathing the same recycled air as everyone else quite as much.” When we find time to get out of the city we’re giving both our minds and immune systems a break. Cold and flu happen most frequently in the winter because people are spending so much time huddled together inside (Heiser).

     In addition, being outside is generally associated with physical activity. That could simply entail a walk through a park or even something more aerobic like running and biking. Being physically active helps keep joints loose and reduce chronic pain and stiffness (Heiser). When exercising outside we are also forced to disconnect from our phones and all the distractions that come with them. This allows us to turn our focus internally and can almost be a sort of meditation.

     It’s almost impossible to research the benefits of nature on the human body without coming across something referred to as “shinrin-yoku,” or as it is known in the US, “Forest Bathing.” It is a therapy method developed in Japan during the 1980s and has become a cornerstone in Japanese preventative health care and healing (Li). The process entails simply spending extended periods of time completely alone in a green “wild” space. Extensive research has shown that “Forest Bathing” can provide us with many health benefits. In addition, as an added bonus, there are neither side effects or costs associated. This may explain why the Japanese trend is so quickly catching on stateside (Heiser).

     Unsurprisingly, the verdict to all this is that our bodies as a whole simply perform better outside. When we think about it, it’s not all that surprising considering that we have evolved over millions of years to live our lives outdoors. We are designed to thrive in the lush forest and expansive plains of the wild, not in our glass and steel cages.

Works Cited

Bangkok Patana school. “The benefits of outdoor learning” SI news, 5              April. 2018                outdoors/. Accessed 1 April. 2019 

Bluth, Rachel. “ADHD Numbers are Rising and Scientists are trying to              figure out why” Washington Post, 10 Sep. 2018.                                   rising-and-scientists-are-trying-to-understan-why/2018/09/07/a918d0f4-      b07e-11e8-a20b-5f4f84429666_story.html                                                            noredirect=on&utm_term=.e1d6be2d34f9. Accessed 1 April. 2019

Heiser, Christina. “How the simple act of nature helps you destress” NBC,      29 Sep. 2018.        solve-life-s-most-challenging-problems-ncna749361. Accessed 1 April.        2019

Louv, Richard. “Last Child in the Woods.” Gifts of Nature, Algonquin               Books, 2008, pp. 7-36

Li, Qing. “Forest Bathing is Great for Your Health, here’s how to do it.”            Time, 1 May. 2018.          Accessed 10 April. 2019

Pope, Tara Parker. “A ‘Dose of nature’ for attention problems” New York        Times, 17 Oct. 2008.        of-nature-for-attention-problems/. Accessed 1 April. 2019

Tys, Tierney. “How Nature Engages your Brain” TED, 13 Feb.                              2017 Accessed 1 April.            2019

Yar, Sanam. “5 Ways Being in nature can change your brain, according to      science” Bustle, 11 Jan. 2019.                nature-changes-your-brain-according-to-science-15827469. Accessed 1        April. 2019

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