Blue spaces

Moderate impact based on moderate quality evidence with moderate resource implications

Impact

Resources

Evidence

Studies

5

Description

Description

Blue spaces are outdoor environments–either natural or manmade–that prominently feature water and are accessible to people [Grellier 2017]. 

Urban blue spaces have been shown to produce significant cooling effects in warmer months when compared to other urban sites [Völker 2013]. Research is accumulating regarding the relationship between blue spaces and health outcomes. 

Impact

Impact

Blue spaces may have positive benefits on human health and well-being. However, the evidence base is limited, the study designs and definitions are variable, and almost all research has been conducted in high-income countries.

Results

Results

A total of five reviews comprising over 150 primary articles were included. One review explored the associations between blue spaces and pregnancy outcomes [Akaraci 2020]. A second review assessed the health and well-being benefits of outdoor blue spaces [Gascon 2017]. Two reviews evaluated the effect of blue spaces on human health [Georgiou 2021; Völker 2011]. A fifth review examined the impact of blue spaces on health in children and the elderly [Kabisch 2017].

Pregnancy

  • There were no associations between blue spaces and pregnancy outcomes [Akaraci 2020]

Mental Wellbeing 

  • There were positive associations between greater exposure to outdoor blue spaces and both benefits to mental health and well-being (n=12 studies) and levels of physical activity (n=13 studies) [Gascon 2017]
  • Being in more contact with blue space was significantly associated with higher levels of restoration (mental health and well-being) [Georgiou 2021]
  • The effect of blue spaces on social interaction is unclear [Georgiou 2021]
  • Emotional and experiential responses to blue space have not yet been sufficiently recognised [Völker 2011]

Physical activity

  • Living in close proximity to blue space was associated with significantly higher physical activity levels [Georgiou 2021]
  • Larger numbers of blue spaces within a geographical area were significantly associated with higher physical activity levels [Georgiou 2021]

Obesity and cardiovascular health

  • The evidence of an association between outdoor blue space exposure and general health, obesity, and cardiovascular-related outcomes was mixed [Gascon 2017]
  • The effect of urban blue spaces on health outcomes in children and the elderly is inconclusive [Kabisch 2017] – This could be due to the degree of access or use of blue spaces

Strength of the evidence

Strength of the evidence

Three reviews reported on the quality of the included primary studies. In [Akaraci 2020], the overall quality of the studies was judged to be medium to high. In [Gascon 2017], 88% of included studies were reported to be of good quality. In [Georgiou 2021], the overall quality of the primary studies was judged as very good.

A major limitation of the current evidence base is the discrepancy in the methods used to measure blue spaces. In a review of 93 articles, the authors reported frequent adoption of fixed spatial units for measuring exposure to blue spaces based on physical proximity, typically ranging from 30 to 5000 m [Labib 2020]. The authors proposed a set of recommendations for standardising protocols and methods for evaluating the impact of green-blue spaces on health. 

Recommendations

Recommendations

  • A standard definition of exposure to blue space that can be used consistently in research studies should be agreed upon.
  • Measurement scales and blue space metrics for universal use should be developed.
  • Further research is required using longitudinal research and natural experiments, preferably across a broader range of countries (especially LMICs), to better understand the relationships between blue spaces, health and wellbeing.
  • Future research should prioritise the relative impact of the quality, amenities, fruition and accessibility of blue spaces to deepen our understanding.
  • ‘Blue’ as a new colour (both literally and metaphorically) should be introduced into debates on environmental health and therapeutic landscapes.

Resource implications

Resource implications

No included review assessed the economic impact of blue spaces. The resource implications are moderate if established during the development phase. However. within existing urban infrastructure, the land requirements will hinder their development.

Related resources

Related Resources

Reference to reviews

Reference to Reviews

Akaraci 2020. “A Systematic Review and Meta-Analysis of Associations between Green and Blue Spaces and Birth Outcomes.” International journal of environmental research and public health vol. 17,8 2949. 24 Apr. 2020, doi:10.3390/ijerph17082949.

Gascon 2017. “Outdoor blue spaces, human health and well-being: A systematic review of quantitative studies.” International journal of hygiene and environmental health vol. 220,8 (2017): 1207-1221. doi:10.1016/j.ijheh.2017.08.004.

Georgiou 2021. “Mechanisms of Impact of Blue Spaces on Human Health: A Systematic Literature Review and Meta-Analysis.” International journal of environmental research and public health vol. 18,5 2486. 3 Mar. 2021, doi:10.3390/ijerph18052486

Kabisch 2017. “The health benefits of nature-based solutions to urbanization challenges for children and the elderly – A systematic review.” Environmental research vol. 159 (2017): 362-373. doi:10.1016/j.envres.2017.08.004.

Völker 2011. “The impact of blue space on human health and well-being – Salutogenetic health effects of inland surface waters: a review.” International journal of hygiene and environmental health vol. 214,6 (2011): 449-60. doi:10.1016/j.ijheh.2011.05.001