Having flown halfway around the world to get to Sydney last week, I decided that a visit to Uluru Kata Tjuta National Park was worth another 3-hour flight to the Australian Outback. A UNESCO world heritage site, Uluru is a sacred place for the local indigenous people. It is also perhaps one of Australia’s most iconic destinations for travelers from around the world. A visit had been on my bucket list for a long time.
It did not disappoint. Uluru is an inselberg, literally “island mountain,” that stands 348 meters high and 9.4 kilometers in circumference. With only the tip of this many-million-year-old red sandstone monolith above ground, it seems to rise up out of nowhere. It is like an iceberg with deep roots below the surface. As I walked around Uluru, despite the jetlag and irritating black flies, I felt great. What is it about a walk in the park that’s so good for us?
City Living and Mental Health Stress. I love living in New York City, and obviously I am not alone. In fact, city living is increasingly the norm around the world. More than 50% of people now live in urban areas worldwide. By 2050, it is estimated that 70% of the world population will live in urban environments. City life has many advantages, including economic opportunity, easy access to culture, education, health services, and community. But everything has a cost, and from a mental health perspective, urbanization is no exception. Urbanization is associated with increased levels of stress and mental health problems, and these findings are particularly true for depression.
A Walk in the Park to De-Stress. Haven’t we all gone for a walk “to feel better” at one time or another? This natural instinct is supported by an abundance of research documenting the mental health benefits of being in nature – not the least of which are improved mood, decreased anxiety, greater social cohesion, and better concentration and attention. How might this work? One mechanism may reside with the parasympathetic nervous system. Spending time in nature has the effect of stimulating parasympathetic activity, which has a calming effect that can take us into states of deep physiological relaxation. Some data suggest that spending time in nature even makes us more resilient to future stressors.
A walk in the Park to Clear our Heads. Rumination, when negative thoughts repeat over and over in our heads, can be a precursor to depression and is disproportionately common among city dwellers compared with people living outside urban areas. Stanford University researchers found that nature helps relieve rumination. Participants who went on a 90-min walk through a natural environment (rather than a 90-minute walk through city blocks) reported lower levels of rumination and showed reduced neural activity in an area of the brain linked to risk for mental illness (the subgenual prefrontal cortex). Time in nature also has the effect of decreasing prefrontal cerebral brain activity, which is the part of the brain responsible for directed attention and executive functioning. It may be the case that respite from effortful attention serves as the basis for recovery from attention fatigue – and may actually be a precursor to attention restoration and vitality.
Shinrin-yoku. Putting these data into practice, the Japanese have grown a cultural practice of shinrin-yoku or forest bathing. Shinrin-yoku means making contact with and taking in the atmosphere of the forest. Researchers in Japan have shown that forest environments, in particular, promote lower concentrations of the stress hormone cortisol, lower pulse rate, lower blood pressure, greater parasympathetic nerve activity, and lower sympathetic nerve activity than do city environments. All of these biological markers are associated with positive health benefit, including mental health. Thus, the cultural practice of spending time in the park in Japan has become an established, if not mainstream, preventive and therapeutic mental health treatment.
Prescribing a Dose of Nature. A walk is great, but simply being in nature is sufficient. You can sit on the bench if you cannot walk, and even small doses of nature – 4-5 minutes – can have beneficial physiological effects. At the same time, there seems to be a dose response effect, with greater duration, frequency and intensity of exposure to nature having commensurate health benefits for people who live in urban settings. A dose-response analysis for depression suggests that visits to outdoor green spaces for thirty minutes or more per week could actually reduce population prevalence of these illnesses by up to 7% and 9%, respectively. With the growing number of studies linking nature to mental health, initiatives like The Shine Program in California that offer “park prescriptions,” may become an integral public health strategy to address the rising rates of anxiety and depression around the world.
Obviously, we don’t need to go to Uluru to enjoy the benefits of nature, and it‘s no wonder that for many New Yorkers, one of the things we love most about our city is Central Park. In fact, the real public health opportunity will be urban development with nature in mind for everyday living.