By Carrie Starbuck
There are multiple studies from the Stress Reduction Theory (Ulrich, 1981), The Biophilia Hypothesis (Wilson, 1984) to Enhanced Immune Functioning (Kuo, 2015) that show connecting with nature has a positive effect on our wellbeing.
To delve deeper into how exactly nature reduces stress, here are five scientific ways nature supports both our physical and mental health.
Phytoncides are naturally occurring chemical compounds secreted by plants and trees or in other words ‘essential oil’. Evergreens such as pine trees, cedars, spruces and conifers are the largest producers of phytoncides. These chemicals or oils have natural antimicrobial and insecticidal qualities that protect the tree from germs and parasites, but they also benefit us too.
Dr Qing Li and his team (2009) have conducted a number of experiments investigating the effects of phytoncides. For instance, in one study 13 healthy men stayed in a hotel in Tokyo for three nights and hinoki stem oil, a cypress oil, was diffused into their rooms whilst they slept. Results showed a 20% increase in the numbers of natural killer (NK) cells and NK activity, enhanced activity of anti-cancer proteins, significantly decreased levels of stress hormones, increased hours of sleep and decreased scores of anxiety and fatigue, whilst the control group saw no changes.
Other studies found phytoncides can be anti-inflammatory by reducing oxidative stress, lowers nervous system activity, has antidepressant properties, enhances sleep and reduces blood glucose levels.
In human history many cultures worshipped the sun for its life giving abilities and with good reason.
Exposure to sunlight is thought to increase the brain’s release of a hormone called serotonin. Serotonin is a neurotransmitter associated with feelings of wellbeing and happiness.
From a powerful source of health and well-being to potential cancer risk, our understanding of the effects of sunlight—and specifically UV radiation—on the body has evolved markedly over the last century. In 1882, German physician and scientist Robert Koch discovered that tuberculosis was caused by a bacteria (myobacterium tuberculosis), which died when left in sunlight. By 1903, Danish physician Niels Ryberg Finsen had treated several hundred tuberculosis patients with ultraviolet radiation from the arc lamps he had invented, an endeavour for which he was awarded the Nobel Prize.
It is thought that ultraviolet light can push melanocytes—the cells that produce dark pigment in skin— to release endorphins, a feel good chemical.
Lastly, exposure to sunlight produces Vitamin D which is important for overall health and wellbeing. It was the lack of exposure to sunlight and thus, vitamin D that in the middle of the 19th century caused rickets, a serious condition affecting bone development in children.
Sunlight, it seems, still has the power to heal and to nourish the body.
Fractals are self-similar patterns that can be found throughout the natural world. Good examples of fractals include snowflakes, plant leaves, tree branches, forests, ocean waves, river systems, coastlines, clouds and galaxy clusters.
Richard Taylor, a nanoparticle physicist, conducted experiments to measure people’s physiological response to viewing images with fractal geometries. He measured skin conductance and found people recovered from stress 60% better when viewing computer images with a mathematical fractal dimension (of between 1.3 and 1.5. Several experiments have confirmed that people generally prefer images with this low to mid-range dimension which is most commonly found in natural phenomena.
Taylor and Hägerhäll, an environmental psychologist, used EEG to measure people’s brain waves, and discovered that viewing computer-generated natural fractals increased alpha wave activity, an indicator of a wakeful, relaxed state and internalised attention. (Hägerhäll et al., 2008, 2015).
This also supports the Stress Reduction Theory (Ulrich, 1981) that shows looking at scenery containing natural elements like greenery or water creates positive emotions and feelings like interest, pleasure, and calm, and has a restorative effect.
4. Natural Sounds
Man-made noise is considered one of the greatest pollutants of modern city living, with the World Health Organisation attributing thousands of deaths every year in Europe to heart attack and stroke caused by high levels of background noise.
Numerous studies have demonstrated the links between noise pollutants and stress. For example, in a German study of 2000 men, environmental noise over 50 decibels was associated with a 20% increase in hypertension.
In a huge study amongst several thousand school children in UK, Spain and the Netherlands living near large airports, there were significant impacts of noise levels in reading comprehension, memory and hyperactivity (Clark et al., 2005).
Listening to nature sounds has the opposite effect. The three most soothing sounds to humans have been found to be wind, water and birdsong (Nilsson, 2006). Psychological studies using birdsong have consistently shown improvements in mood and mental alertness (Radcliffe, et al. 2013).
Interestingly, people’s preferences for the sounds of nature may have an evolutionary basis as we associate birds singing in the morning with alertness and safety, and running water with a clean fresh water source.
Scientists have been studying the complex and mysterious emotion called awe. A growing body of research suggests that experiencing awe may lead to a wide range of benefits, from happiness and health to perhaps more unexpected benefits such as generosity, humility, and critical thinking.
We may believe to experience awe we must go on an epic journey to the Grand Canyon but a study by Joye and Bolderdijk (2015) showed participants a slideshow of awesome versus. mundane nature images. They found that watching awesome natural scenes had unique and pronounced emotional effects such as feeling small and humble, and triggered the most mood improvement.
This is good news as it shows that awe does not have to be an emotion reserved for the most extraordinary moments such as, climbing a mountain or witnessing the birth of a child, but rather every-day moments of wonder can have the same impact on our health and wellbeing.
Slowing down to be present and notice the world around us can help to make daily experiences of awe the way we engage with the world.
Ulrich, R. S. (1981). Natural versus urban scenes: Some psychophysiological effects. Environment and Behavior, 13, 523–556.
Li, Q., Kobayashi, M., Wakayama, Y., Inagaki, H., Katsumata, M., Hirata, Y., … Miyazaki, Y. (2009). Effect of Phytoncide from Trees on Human Natural Killer Cell Function. International Journal of Immunopathology and Pharmacology, 951–959.
Mandelbrot, B. & Wheeler, J. (1983). The Fractal Geometry of Nature. American Journal of Physics, 51, 286.
Hägerhäll, C., Laike, T., Kuller, M., Marcheschi, E., Boydston, C., & Taylor, R. (2015). Human physiological benefits of viewing nature: EEG responses to exact and statistical fractal patterns. Nonlinear dynamics, psychology, and life sciences, 19, 1-12.
Alvarsson, J., Wiens, S., & Nilsson, M. (2010). Stress recovery during exposure to nature sound and environmental noise. International Journal of Environmental Research and Public Health, 7,1036-46.
Kaltenbach, M., Maschke, C., & Klinke, R. (2008). Health Consequences of Aircraft Noise. Deutsches Ärzteblatt international, 105(31-32).
Clark, C., Martin, R., van Kempen, E., Alfred, T., Head, J., Davies, H. W., Haines, M., M. Barrio, I., L Matheson, M., & Stansfeld, S. A. (2005). Exposure-effect relations between aircraft and road traffic noise exposure at school and reading comprehension: the ranch project. American Journal of Epidemiology, 163(1), 27-37.
Nilsson, M., & Berglund, B. (2006). Soundscape quality in suburban green areas and city parks. Acta Acustica United with Acustica, 92( 6), 903-911.
Ratcliffe, E., Gatersleben, B., & Sowden, P. (2013). Bird sounds and their contributions to perceived attention restoration and stress recovery. Journal of Environmental Psychology, 36, 221-228.