A Brief Supplement to Blue Mind

Last week BBC Future published an extensive article listing some of the expanding body of evidence-based research on the emotional health benefits of “blue space”. 

Among the work cited was a study in Landscape and Urban Planning that found time in nature linked to reduced physical markers of stress: our heart rate and blood pressure both tend to go down. We also release more natural ‘killer cells’: called lymphocytes that roam throughout the body, hunting down cancerous and virus-infected cells.

Our 2016 study published in Environment & Behavior found viewing aquarium displays led to noticeable reductions in blood pressure and heart rate, and higher numbers of fish helped to hold people's attention for longer and improve their moods. This suggests higher biota levels, even in managed settings, may be associated with important well-being and health benefits, particularly for individuals not able to access the natural analogues of managed environments.

Amber Pearson, a health geographer at Michigan State University, hypothesizes that “natural spaces act as a calming backdrop to the busy stimuli of the city. From an evolutionary perspective, we also associate natural things as key resources for survival, so we favor them.” 

In her 2017 paper she described the three primary theoretical pathways through which blue space benefits health.

1) visual exposure to natural spaces as a calming backdrop and the subsequent mental health benefits; 

2) use of blue spaces engages physical activities, maintaining a healthy weight, lowering blood pressure, and obtaining other physical health benefits; and 

3) blue spaces may promote social connections, as venues for recreation (e.g., boating, swimming, picnics, fishing), with concomitant benefits to both physical and mental health. 

A 2016 study conducted in New Zealand by Pearson and her colleagues found residents with ocean views had lower levels of psychological distress. 

Pearson says, “One might expect that a 20 to 30% increase in blue space visibility could shift someone from moderate distress into a lower category.” Similar results were found in a follow-up study conducted near the Great Lakes in the US (in review) and Hong Kong residents in an upcoming study by University of Exeter psychologist Mat White.

A 2018 study published in PLoS ONE found that “float therapy” participants reported significant reductions in stress, muscle tension, pain, depression, and negative affect, accompanied by a significant improvement in mood characterized by increases in serenity, relaxation, happiness and overall well-being.

Furthermore, a 2017 paper, Accessing Blue Spaces: Social and Geographic Factors Structuring Familiarity With, Use of, and Appreciation of Urban Waterways, published in Landscape and Urban Planning that found evidence supporting the idea that “urban waterways are positive amenities for neighborhood quality of life”.

While still limited in number, a 2017 review of quantitative blue space research found the balance of evidence suggested a positive association between greater exposure to outdoor blue spaces, benefits to mental health, well-being, and levels of physical activity. 

The authors state that “further research is needed using longitudinal research and natural experiments, preferably across a broader range of countries, to better understand the causal associations between blue spaces, health, and wellbeing”.

Cracknell, D., MP White, S Pahl, WJ Nichols, MH Depledge (2015) Marine Biota and Psychological Well-Being: A Preliminary Examination of Dose-Response Effects in an Aquarium Setting. Environment and Behavior, 2015; DOI: 10.1177/0013916515597512

Feinstein JS, SS Khalsa, H-w Yeh, C Wohlrab, WK Simmons, MB Stein, et al. (2018) Examining the short-term anxiolytic and antidepressant effect of Floatation-REST. PLoS ONE 13(2): e0190292. https://doi.org/10.1371/journal.pone.0190292

Pearson, AL, R Bottomley, T Chambers, L Thornton, J Stanley, M Smith, et al.. (2017). Measuring blue space visibility and 'blue recreation' in the everyday lives of children in a capital city. International Journal of Environmental Research and Public Health, 14(6), 563. doi: http://dx.doi.org/10.3390/ijerph14060563