It's easy to get caught up in our modern world and forget about our roots. We all lead busy lives and from working or studying to running errands, to making dinner, the vast majority of us spend all of our day indoors or driving between indoors. For most of us, spending time outside, among nature, is a luxury rarely afforded. While we all know that remaining cooped up in our homes and offices strains our sanity, recent studies have confirmed that it takes its toll on our physical health as well.
But how can nature, or the absence of it, actually affect our wellbeing? Well, the long answer involves psychological and physiological responses in the brain releasing helpful hormones and chemicals while in nature, and the brain not doing so in urban environments. Dr. Ming Kuo of the Department of Natural Resources and Environmental Sciences gave a TED Talk (Vitamin N) detailing such effects. In her talk, Kuo states that the blood of someone walking through a natural space will have elevated levels of adiponectin and Da Ta, chemicals that improve your cardiovascular health and help fight diseases like atherosclerosis. Additionally, walking through natural environments measurably decreases one's blood pressure, lowering chances of heart disease. Interestingly, the same walk through an urban center yielded none of these benefits (Kuo, 13:30.)
Professor Ming Kuo delivering her TED Talk, Vitamin N (the N stand for nature)
Dr. Kuo also explains the profound effect nature has on mental health. A significant portion of her research revolves around Attention Deficit Hyperactivity Disorder, particularly in children. If you've been paying attention, you will have already guessed that time spent in a natural environment, even a community park, reduces the symptoms of ADHD in schoolchildren and even increases concentration for a time after the walk. (Kuo 9:30)
A 2015 study published in the Proceedings of the National Academy of Sciences by Gregory Bratman, et. al. revealed complementary results. This study, Nature experience reduces rumination and subgenual prefrontal cortex activation demonstrated that a 90-minute walk through the woods reduced [one's] neural activity in an area of the brain linked to risk for mental illness. Not only would natural walks decrease the chance of mental illness, but of the participants studied, those on the natural walk showed less rumination, clinical, obsessive over-thinking linked to depression.
Graphs from the PNAS study showing a marked decrease in rumination and a decrease in Subgenual Prefrontal Cortex Perfusion in subjects after walking in nature vs subjects walking in urban cities.
There is even evidence to show that time spent in nature can reduce the effects of Post-Traumatic Stress Disorder. In a recent article (Nature as Medicine) by POST, a Silicon Valley-based organization dedicated to preserving and protecting open and natural space, author Matt Dolkas shared the story of Stacy Bare, U.S. Army Veteran turned avid hiker. After returning from deployment in Bosnia and Iraq, Bare, suffering from PTSD and alcoholism, found an effective treatment in the form of rock climbing in Open Space Parks in Boulder, Colorado. To quote Bare, "Our open spaces are our best public health and preventative health care system."
Stacy Bare hiking in an Open Space Park in Colorado
The short answer to why nature has such a profound effect on our bodies is simply this: cities and suburbs are not human being's natural habitat. Human beings have been around for nearly 200,000 years, evolving and adapting to live with nature, while modern, urban living people have only been around for a fraction of that time. Philosophers before us have suggested that we live in a kind of self-imposed captivity, isolated from the natural world. Now we have science to back up this philosophy, with evidence to suggest that our segregation from nature takes a physical toll on our bodies.