The development of a more structured society has given rise to urban environments. With more opportunities for education and employment, many individuals migrate from rural areas to larger cities. While there are benefits, many drawbacks like obesity, stress, and poor mental health have also increased during this development. Additionally, densely populated areas experience competition for space. As a result, there has been a decrease in natural environments individuals in urban landscapes are exposed to. Interestingly enough, Japanese culture places a large emphasis on taking time to indulge oneself in nature. The word for this practice is “shinrinyoku” which means “forest bathing.” The idea is to use all of one’s five senses to experience the natural landscape. This practice has been noticed by Western culture and gained attention from many researchers. In an effort to tackle poor affect specifically, many studies examine the role nature plays and its potential to reduce stress, anxiety, and depression.
A study by Daniel T.C. Cox et. al examines the role nature plays in human health. Nature exposure was broken down into three dimensions: frequency, duration, and intensity. Frequency refers to how often individuals visit nature landscapes, duration refers to how long they stay in these landscapes, and intensity refers to “how much” nature an individual experiences. The researchers found from this study that an individual’s intentional engagement with nature could be a driving force for the benefits (reduction in depression and high blood pressure levels). This means that it could be important for individuals to be mindful while in nature—trying to connect to their experience instead of passively living in the moment. They also found a positive association between nature connectedness and life satisfaction and happiness.
One important limitation researchers note is that due to urban-living individuals having to travel long distances to visit natural landscapes, the duration of visits will most likely be short (under thirty minutes). The researchers suggest that building community gardens can be beneficial and reduce the burden of finding a park or other natural environment far from an individual’s home. The small duration of time spent in nature can be compensated with more frequent visits. A second limitation is the inability to draw causal conclusions. It may very well be that nature itself is not reducing depression, but instead acting as a mediator. Those who frequently visit natural landscapes report better social cohesion and more positive views of their community. It could be that depression levels decrease due to feeling more socially connected to the community as opposed to being in nature alone.
One proposed mechanistic pathway for the reduction in high blood pressure is that nature is able to restore attention. With an increasingly busy lifestyle, humans are frequently exhausting their attention and, as a result, feel burned out or stressed. Nature is able to relieve this mental fatigue. Additionally, researchers note that those who garden at least one day a week experience less stress and experience more positive affect than those who do not go outdoors at all. Researchers hypothesize that nature could be a protective factor against mental fatigue in urban living: overcrowding, pollution, and a busy lifestyle.
A separate study by MaryCarol R. Hunter, Brenda W. Gillespie, and Sophie Yu-Pu Chen sought to examine the impact of urban nature experiences and stress. Researchers measured salivary cortisol and alpha-amylase levels—two biomarkers of stress. Their findings showed that cortisol levels dropped 21.3% an hour and amylase levels 28.1% per hour with the greatest efficiency between 20 and 30 minutes. Benefits continue to accrue at a reduced rate after that. The researchers explain that because it is difficult to incorporate self-care into a busy routine, it is important to find the minimum duration needed in nature that yields maximum benefits. It is also important to note that researchers controlled for diurnal drops of cortisol and alpha-amylase levels when they reported their statistics.
One limitation of this study is how amylase is sensitive to both physical exertion and the sunset. To control for the latter limitation, data were only used from nature experiences that ended before sunset time. Amylase levels barely decreased when participants walked casually; however, amylase levels dropped significantly when participants took time to sit in nature. This was a result the researchers were not expecting. Additionally, a second major limitation is seen in the construct of the experiment: participants were self-selected and able to choose their own nature experiences. There could be, as researchers note, a bias in the results if only people who are motivated to experience nature were used in this study. For future research, the experimenters recommended using a more diverse sample of participants and a more controlled natural environment.
Ultimately, the increasing levels of stress and depression individuals living in large cities experience have become concerning. While the causal relations between nature and affect are not certain, there has been data showing nature experiences are able to reduce stress-related biomarkers: cortisol and alpha-amylase. There are also positive associations between intentional nature experiences and the reduction of depression symptoms. When having a stressful week, following the Japanese shinrinyoku practice could very well help to reset the mental fatigue and offer a break from the stress city living brings.
Cox, D.T.C., Shanahan, D.F., Hudson, H.L., Fuller, R.A., & Gaston, K.J. (2018). The impact of urbanisation on nature dose and the implications for human health. Landscape and Urban Planning 179, 72-80. https://doi.org/10.1016/j.landurbplan.2018.07.013
Hunter, M.R., Gillespie, B.W., & Chen, S.Y. (2019). Urban Nature Experiences Reduce Stress in the Context of Daily Life Based on Salivary Biomarkers. Frontiers in Psychology 10(722). https://doi.org/10.3389/fpsyg.2019.00722
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