“There are no individuals. There are no species. Everything in the forest is the forest.”
From “The Overstory” by Richard Powers
News flash: spending time in nature is good for your health. Most likely you are not surprised. Anyone who has spent time sitting by the ocean, climbing a mountain, or just strolling along a wooded path knows that being in a natural setting can foster an overall sense of well-being. Most of us know that even a short walk through a park can reduce stress, boost our mood, and make us feel better. A rapidly expanding body of research is confirming what most people know experientially: being in nature has robust effects on our health, providing physical, mental, and emotional benefits that cut across occupations, ethnicities, and all economic groups. Each decade of study provides more evidence that nature is not just a nice place to visit but is vital to the quality of our lives. Nature is an essential part of being human and we pay a deep cost when we lose contact with it.
Although many scientists, physicians, health educators, and even preachers have for centuries extolled the health benefits of being in the great outdoors, it has only been in the past twenty years that research has sought to measure the impact nature has on our health. To date, we know that time spent in nature is a powerful tool for reducing stress. Spending time in nature lowers blood pressure and cortisol levels, leading to less inflammation and improved immunity. It also improves the overall quality of sleep, including our ability to fall and stay asleep. In addition to physical benefits, being in nature has been shown to reduce anxiety and depression while promoting positive emotions such as serenity, curiosity, and awe. Cognitively, it improves our problem-solving skills and memory retention while leading to increased attentional control and decreased ADHD symptoms. Interestingly, those who report spending more time in natural settings tend to express higher levels of life purpose and a desire for social engagement.
Some research suggests that simply looking at nature scenes is enough to stimulate its stress reducing benefits. Studies have found that windows providing natural light while overlooking green spaces create a more cooperative and creative workspace, while patients heal faster when placed in hospital rooms with windows that offer views of gardens or trees. But several researchers question the long-term benefits of purely visual stimuli such as pictures and windows, emphasizing that nature heals us because it is an immersive experience that simultaneously engages all the senses—sight, sound, smell, touch, and movement. Very few human-made environments engage our senses in the same way as nature. By simultaneously stimulating all the senses, the communication between the nervous system and the brain improves, becoming smoother and more refined, resulting in more coordinated and fine-tuned movements. Data gathered from wartime statistics showed that soldiers raised in natural settings such as farms, ranches, and fishing communities were better equipped for the battlefield than those raised in urban settings. They were better at integrating information from all their senses, making more skillful combat decisions. We need only to look back to the early days of the pandemic to see how nature enhances our sensory coordination: when people ventured outside after months of being sequestered indoors during the early days of the pandemic, the number of falls that resulted in serious injuries skyrocketed. Physicians attributed the spike to the extended time inside, away from the immersive property of being outdoors, lacking the stimulation that natural environments provide the senses.
In addition to its general health benefits, we are starting to learn more about the specific ingredients that make nature such a powerful elixir and how each of the senses are shaped through interaction with our natural world. These ingredients can be quite subtle, such as what Japanese researchers refer to as “forest bathing”, in which people go for walks in the woods specifically to access certain chemicals released by trees that have been shown to improve immunity. Trees emit aerosols to communicate with one another, and when these are inhaled by humans, they elevate Natural Killer (NK) cells in the immune system which have been shown to defend the body against tumors and infections. Other subtleties can be found in the soils in our environments. The University of Colorado Boulder has identified a benign soil-dwelling bacteria that has immune-modulating and mood-altering properties when injected into experimental mice. The thinking is that this bacterium, along with other microbes in the soil, co-evolved with humans and may have developed the power to boost our health. Studies of children living in farms in Germany who are exposed to these microbes in the soil have lower rates of allergies and asthma, suggesting a beneficial relationship with these microbes.
Whereas human designed structures like houses, buildings, malls, and skyscrapers tend to follow patterns made up mostly of straight lines, nature’s patterns are much more complex, full of shapes with never-ending patterns. Fractals in nature are geometric shapes that look the same no matter their size—big or small. They are ubiquitous in nature, and we encounter them every day. Pineapples, pinecones, and succulents grow according to fractal laws, and the ice crystals that form snowflakes form fractal shapes. Trees are one of the most ubiquitous examples of fractals. As they grow, branches sprout from their trunks, each growing into smaller tree shapes; these branches continue the pattern when new branches sprout from them. Fractals serve an important purpose in nature; for trees and plants they optimize their exposure to the sun and allow more nutrients to reach the plant’s core.
For humans, fractals provide a source of visual fluency—the eye pleasing appeal inherent in a never-ending pattern--that is lost in much of our human-made construction. Humans prefer visual patterns that have a specific range of complexity, and fractals found in nature seem to have just the right amount. Viewing these patterns is so appealing that it increases our brain’s alpha waves, the same thing that happens when we are meditating or engaging in a mindfulness practice. Essentially, fractals in nature help us to relax while staying alert and present. Studies have found that increased exposure to these images can reduce stress by as much as 60%, depending on the length of time spent in nature.
Over 90% of people cite enjoyment of the quiet and serenity of nature as their top reason for visiting a national park. Human noise has been growing at significant rates over the past 30 years; it is well documented that the noise we create disturbs animal migration and communication patterns, as well as the health of our insect populations, coral reefs, and oceans. But environmental noise takes a big toll on human health as well; spend only a few hours in a busy urban setting and you’ll notice a marked increase in your respiratory rate, blood pressure, and cortisol levels. Noisy environments reduce our attention levels, decrease our capacity to learn, and impair our memory. Human made noise also makes us feel less connected to others, making us more likely to describe social interactions negatively.
Of course, not all sounds in nature are pleasing—it is important to our survival that we respond strongly to sounds associated with danger. There are, however, three types of sounds that are especially appealing to the human ear: birdsong, wind, and water. These three sounds have been found to be especially relaxing and are associated with improved mood. Of course, there are variations and individual differences--a squawking crow or a howling wind can be annoying or even stressful for many. Generally, however, most people find moderate versions of at least one or two of these sounds relaxing.
Perhaps one of the strongest influences nature has on our health is in its power to shift and restore our attention. In a typical office setting, we are exposed to 11 million bits of information per second, but our brains can only process about 120 bits per second. Other human-made settings—malls, stores, highways, cities, schools--can flood us with similar levels of information, which is compounded by the steady stream of stimulation from our phones. In stimulation-rich environments, the brain responds to overload by narrowing our attention and focusing more acutely on only a few selected areas of information. With narrowed attention comes a steady increase in stress related hormones, muscle tension, elevated heart rate and blood pressure, all setting the stage for inflammation. Over time, narrowed, directed attention fatigues the brain and cognitive performance begins to deteriorate. We become more impulsive, impatient, and distracted. It is harder for us to make good decisions and engage in effective long-term planning, with abstract goal planning becoming more difficult. Even our social relationships start to suffer.
Busy human-made environments engage what scientists refer to as “hard” fascination, which requires what is referred to as directive attention, which includes analyzing, problem-solving, evaluation, and judgment. Natural environments can also be busy, but they have an element of mystery that appears to engage our attention differently, in what is described as a “soft focus”, one that is alert but expansive. It is a type of attention in which we are aware of our surroundings, but not hyper focused on one particular area or engaged in effortful concentration or analysis. This is the same type of attention cultivated in mindfulness practices; as such, being in nature has been found to stimulate the same alpha waves that are present in those who are meditating.
Nature can reset our attention but does so at a level that offers more than just a small brain break. Studies have found that, with the right amount of exposure to a natural environment that is pleasing to the individual, spending time in nature heals us by restoring the brain, leading to improved mental clarity and enhanced cognitive performance. We have decades of research supporting the healing properties of mediation and mindfulness; being in nature provides the same outcome without the need to learn how to meditate. Given that it is an immersive experience that calms all the senses, spending time in nature is perhaps the most seamless step we can take to improve our health.
There are some caveats, of course, as to how nature will impact us. Studies have shown that the restorative benefits of nature are severely dampened when using a phone. People who are actively texting, talking, or taking pictures on their phones while in nature do not experience as many benefits as those who are fully present. Likewise, people who come to nature to accomplish a specific outcome-oriented goal are less likely to experience the restorative benefits to their attention, nor do they experience significant reductions in stress levels beyond what would be experienced in a typical exercise session. The clear message is that nature works its magic when we turn off the phone, disconnect from our habitual activities, and tune into the natural world around us. And, of course, the setting must be one in which we feel safe and that is pleasing to us. Someone who hates mosquitoes and has an outsized fear of bears will not feel calm and serene if they hike in the Alaskan wilderness during the height of summer.
As we go through May, we’ll explore how nature helps us heal and improves our health. We’ll look at the benefits of exercising outside versus inside, the impact microbes have on the nutrients in our food, and how nature can shift our mood and elevate our emotions. As we go through the month, I hope to expand your awareness and appreciation of the natural world and the power it holds to help us build a healthy and balanced life. As we look ahead, I invite you to consider your relationship to the great outdoors. What is it in nature that draws you to it? What stimulates your curiosity about the natural world, and which parts bring a sense of calm? Nature can inspire a sense of adventure in all of us. I invite you to look out at the horizon and be open to where it may take you.