The Undeniable Power of Green and Blue Environments

A Brief Overview-Green Environments.

Spending time in and around green spaces provides a multi-sensory experience with a range of beneficial physiological and psychological outcomes. Green spaces such as forests provide a link between nature and health that is supported by empirical evidence.

Green environments such as forests are rich in aromatic antimicrobial volatile organic compounds - phytoncides; part of the plants defense system. The cedar tree, among other forest plants, has been associated with the release of health-protecting phytoncides, especially at warmer temperatures. Phytoncides have been linked to supporting not only plant life, but also human immune system function through a mechanism that increases NK (natural killer) cell activity in humans. NK cells have been shown to recognise and destroy cancerous tumor cells. 

Greater exposure to green spaces have been shown to increase the types of skin and nasal microbiota, which may support immune regulation. Further, a study in mice documented antidepressant effects and increases in serotonin levels following exposure to soil containing Mycobacterium vaccae (M.vaccae), paving the way for future human studies investigating the potential psychophysiological effects of M.vaccae during gardening activities, and the possibility of treating persons with M.vaccae for psychological disorders such as post-traumatic stress disorder.

Simply walking in green spaces can reduce cognitive load, improve self-perceived mood, induce parasympathetic activity and reduce short-term anxiety. Empirical evidence has supported physical activity in green spaces for reducing stress markers such as salivary cortisol levels (used as an indicator of stress, and while not all stress is damaging, chronic elevated cortisol levels are associated with inflammation and decline in health), lowered blood pressure and heart rate, reduced inflammatory cytokines, increased activation of the prefrontal cortex, and improved attention in people with ADHD. 

Walking in green spaces can evoke feelings of awe and fascination, which can help reduce negative thinking such as rumination, while increasing perceived feelings of vitality and restoration, making it a potential option for those experiencing burnout.  Walking in green woodlands has also been shown to produce greater reductions in stress levels and improvements in mood and well-being than urban walks.

In addition to the organic compounds present in woodland and green park environments that are beneficial to human health, researchers have developed theories to explain the potential relationship of why people would experience mental restoration during time spent in, or simply viewing the natural environment, without physically being immersed in it e.g. viewing images, viewing a window view of a green space, or with virtual reality.  

Kaplan & Kaplan's Attention Restoration Theory (ART) is a popular theory which attempts to explain the value and mechanisms of green and blue spaces in restoring attention and offering relaxation. ART posits that people can experience relaxation by the gentle and effortless fascination of green spaces. These spaces provide a respite from the distracting and demanding hustle and bustle of urban lifestyles requiring more cognitive load. A green natural environment provides a seamless and effortless shift of attention to the varied sights, sounds and smells of nature, offering rest of cognitive processes and ultimately attention restoration.

Further, Wilson's 1984 biophilia hypothesis (from the ancient Greek root words: bio (life) and philia (affection, love), posits the natural affinity of humans to connect with nature, explained through human evolution and our consistent proximity and dependence on nature for survival, food, and security. Our captivation to nature may have a biological, innate instinct in us to connect with certain elements in nature. The incorporation of biophilic design in healthcare can be seen throughout history with the inclusion of courtyard gardens in hospitals and monasteries. 

Green Space

Natural environments with plant life (forests, urban parks, meadows).

Green spaces may also be incorporated into urban areas.

Outdoor water environments and urban blue spaces either natural or man-made (lakes, rivers, coastlines, streams). 

Physical activity in these environments can be land or water-based. 

Physical activity in natural environments with vegetation. 

Green exercise facilitates healthy physiological and psychological outcomes.

Blue Spaces for Physical Activity and Psychological Health.

Evidence suggests that people living near coastal blue spaces report increased levels of physical exercise and better levels of mental health than those living farther in land. There is evidence to suggest that outdoor blue spaces have the potential to elicit greater perceived well-being, reduced feelings of psychological distress, and decreased feelings of depression.

Blue spaces such as coastal towns, are popular destinations for recreation and attract large groups of tourists. Coastal regions and bodies of water are highly desirable spaces to which many people are naturally drawn to; whether it is active viewing / participation with walking or running on the beach, cycling along coastal regions, and water activities, it also attracts people for passive viewing- being in proximity and enjoying the view of blue spaces, and sitting in a restaurant by the sea or lake can elicit feelings of well-being such as relaxation. The exact mechanisms and conditions needed to explain this phenomenon are not yet determined. 

The potential mediating role of physical activity and its association with health and well-being in blue spaces is being investigated further. Current evidence suggests exposure to blue spaces, and a mix of green and blue spaces such as riverside parks can improve physical activity levels and psychological health of residents.