News and conversations about the growing evidence of the healing power of nature and green development in cities
We are approaching nearly 40 years of research about the linkages between nature experiences, human disease prevention, and health promotion. As more people move into cities, nearby nature spaces that provide mental and physical health benefits are needed more than ever. Recent research reveals the effects urban noise and distractions have on our minds and bodies, and suggests ways in which nearby tranquil spaces alleviate stress.
The amount and character of noise – or the acoustic landscape – is surprisingly important to human health and well-being. At one extreme, sounds have been used in warfare and in torture, as deafening aural assaults are used to break resolve and willpower. In contrast, music may be used to improve moods and satisfaction in the workplace and life. People often seek quiet or relaxing sounds of nature to recover from a stressful day or simply to relax and decompress. Findings from multiple studies show that persistent, loud noise (e.g., traffic) causes non-auditory stress effects. The list of undesirable effects is staggering: elevated blood pressure, poor sustained attention, memory/concentration problems, sleep disturbances, modifications of social behavior, psychosocial stress-related symptoms, annoyance, and learned helplessness.
A study in the U.K. found that even moderate sound levels can cause feelings of disturbance, increased blood pressure, increased risk of heart attacks, decreased well-being and quality of life, and stress reactions and sleeplessness. A long-term study of thousands of individuals in the Netherlands found associations between exposure to road traffic and neighborhood air pollution, and cardiovascular events. In another study, those with access to a quiet side of their home, not exposed to traffic or disruptive noises, had lower stress-related psychosocial symptoms and improved sleeping patterns than those always in a noisy environment. More detail and citations on these studies is available in the Sacred and Nearby Nature brief.
Sound can impact our quality of life and mental health. Noise can make it more difficult to learn and apply cognitive thinking skills, whereas ‘quiet time’ provides benefit. The term “constructive internal reflection” describes what happens in the brain during quiet time. Mental rest improves the ability to recall personal memories, imagine the future, and feel social emotions with moral connotations. Research has even revealed that development of some socio-emotional skills may be vulnerable to disruption by distraction. In other words, the more time you spend in loud, disruptive environments may mean your brain has less time for empathy. Setting aside quiet time for meditation and simple rest is recommended, however, finding a quiet space can be a challenge in many urban environments.
Green space, particularly trees and large shrubs, can reduce ambient noise by providing a barrier or screen. Vegetation can be used to dampen and reduce noise, by providing a noise barrier as well as softening sharp tones. Research suggests that dense planting reaching to the ground and with no gaps may achieve noise reductions of up to 15 decibels (most people can notice the difference in a few decibel level changes). Being in the midst of vegetation can affect the perception of sound as well. In a study of soundscapes, researchers compared subjective ratings to objective decibel measurements. They found that people rate human-made and natural sound differently, preferring the natural even if the sound levels are high. In a similar study, participants rated loud biological noises (wind, water, birds) as desirable, suggesting that a tranquil experience can be engineered within urban environments.
Nature encounters are associated with desirable physiological responses. Our bodies may do better when we experience nature, and in ways that we may not even consciously realize. For instance, studies in Japan about Shinrin-yoku, roughly translated as ‘forest bathing’, have found lower levels of salivary cortisol (a hormone indicator of stress) after short times spent walking in or viewing forest areas. The autonomic nervous system (ANS) is the behind the scenes control for many bodily functions, and reacts based on our experiences of our surroundings, including relaxation or stress. An additional study found that views of nature buffered negative ANS response to an introduced stressor, or in other words, a dose of nature ‘immunized’ a person against a later stress experience. Researchers have linked positive emotions – especially the awe we feel when touched by the beauty of nature, art, and spirituality – with lower levels of pro-inflammatory cytokines; these are proteins that signal the immune system to work harder.
Meditation is an act of intentional focus on any number of things – breathing, repetition of a word or phrase, an object in the visual field, tension or physical sensations, or specific thoughts or personal reflections. Benefits of meditation include lowered heart rate, lowered blood pressure, improved metabolism, improved respiration, improved cognitive functions, longer attention spans, and improved perceptual ability, memory, intelligence, and empathy. Some research has found that practicing meditation may reduce stress-induced immune system decline and behaviors. Scientists are not yet sure why these responses occur, but generally agree on the benefits.
Mindfulness is described as ‘‘being attentive to and aware of what is taking place in the present’’ with resulting benefits. Mindfulness enhances self-regulated functioning; that is, mindfulness sensitizes individuals to intrinsic signals, allowing people to better regulate themselves toward meeting their needs. Mindfulness enhances the richness and vitality of moment-to-moment experiences. Mindfulness training may also improve attention-related activities (such as work or study) by enhancing some specific brain areas that support attention. In a study that included training on mindfulness meditation, those doing meditation (compared to a control group not doing so) had increased brain patterns associated with positive affect and significant increases in antibodies available to fight influenza after injection with a flu vaccine.
Certain experiences or environments may promote the meditation, mindfulness, and simply sitting still for a moment. The enhanced sensory influences of nature nearby spaces can support a state of mindfulness and meditative practices. For example, a study using a mobile EEG tracker connected to walkers’ brains showed evidence of higher levels of brain activity similar to meditation when moving in green space, versus when within built settings having no trees. Follow up studies using mobile EEG are taking place this year.
Small, enclosed nature spaces in cities provide quiet spaces to relax, meditate and restore. To find ways to promote these spaces in your neighborhood, check out the latest Research Briefs on Elder Health, Civic Sacred, Stress and Mental Health.