by Maryanne Edmundson, Ph. D., L.P.
Mental health professionals have recently become interested in the effects of humans’ increasing separation from the natural world, including potential effects on cognition. Although research in this area is relatively new, some studies have shown that increasing our exposure to nature may be beneficial to our brains through complex mechanisms.
Thus far, studies have linked nature exposure to improvements in attention, memory, and spatial perception. For example, studies comparing cognitive performances of individuals asked to spend time in natural environments (i.e., forests, parks) vs. people who spent time in urban settings (e.g., a city block without much natural scenery) have found that, for those who spent time in nature, children with ADHD performed better on attention tasks and people with depression performed better on memory tasks. Among children in similar socioeconomic situations, those with more access to green spaces have better impulse control, less hyperactivity, more creative play, more emotional resilience, and better social interactions. Adults with greater nature accessibility also tend to demonstrate lower impulsive decision-making and expanded space perception (i.e., better perception of larger visual areas). Additionally, a study of older adults showed that those who did not go outdoors regularly tended to have faster declines in daily functioning and intellectual activities over a 9-month span than those who regularly went outdoors. Attentional benefits are notably better for real-world nature exposure (e.g., walking in a forest) than simulation (e.g., watching a nature film), though both show some attention boosts.
Some researchers have posited that this restorative effect of nature exposure relates to the reduced demand on executive functioning-based attention (i.e., giving a break to our highest-level ability to selectively focus our attention). Others hypothesize that nature’s brain boost occurs specifically through mood control, given that individuals with greater exposure to nature have generally been found to have less depression, anxiety, and stress, be more socially active, and have a greater sense of wellbeing, relaxation, and feelings of self-efficacy – however, sometimes nature’s boost to memory performance has been found even when mood does not improve, suggesting there is more to the story than just emotional effects.
Many studies show health benefits of exposure to nature that have implications for brain health. Exposure to natural spaces has been linked to activation of the parasympathetic nervous system, the body system that helps us to physically relax and rejuvenate, and lowered activation of the sympathetic nervous system, which gives us our “fight or flight” response to stress and danger – thus, our bodies may be literally less stressed when in nature. Nature therapies, or intentional exposure to nature for health promotion, have shown results of reduced blood glucose in people with diabetes, cortisol levels (a stress hormone), heart rate variability, blood pressure, and pulse rate, shorter surgical recovery times, and boosts to certain immune functions in individuals with weakened immune systems and those undergoing cancer treatments. Improvements in cardiovascular and immune health are protective factors against the development of cognitive disorders, such as some dementias, and may improve overall disease course in certain neurological autoimmune conditions, such as multiple sclerosis. Additionally, exposure to sunlight contributes to greater vitamin D production (a vitamin necessary for brain health) and regulation of the sleep-wake cycle (which helps our brains to rejuvenate more efficiently during sleep). A new area of interest is the gastrointestinal microbiome, the unique collection of helpful microbes living in our guts. Studies suggest that early exposure to microbe-rich environments (e.g., growing up on a traditional farm with microbially diverse soil) may increase microbiome diversity which may in turn protect against the development of inflammatory and autoimmune conditions and improve brain cell communication in the hippocampus (the brain’s learning center). Thus, cognitive boosts from nature exposure may occur by improving health factors that affect brain performance.
Before you embark on a new nature trip, discuss any risks with your primary doctor (e.g., allergies and other health factors) to ensure you have the best possible nature experience. If you have additional questions about cognitive functioning and nature exposure, consult with your local neuropsychologist.
Dr. Maryanne Edmundson is a clinical neuropsychologist at Pinehurst Neuropsychology Brain & Memory Clinic. She can be reached at 910-420-8041 or through the website at www.pinehurstneuropsychology.com.