Unlocking the secrets of green and blue space for mental health

Posted on 18th March 2024

Key publications stemming from The Green and Blue Spaces Project are helping to shape our understanding of the effects of Green and Blue Spaces (GBS) on our mental health and helping to guide future research.

Funded by NIHR, the project is a collaboration with researchers at the University of Exeter, Swansea University, the University of Liverpool, Cardiff University and the Barcelona Institute for Global Health.

Throughout the Project, researchers used routinely collected health and environment data linked in the Secure Anonymised Information Linkage Databank (SAIL), which brings data together securely and confidentially.


A key piece of research, published in Nature publishing’s Scientific Reports in June 2023, explored the connections between natural environments, wellbeing, and socioeconomic factors. Using data from the National Survey for Wales, linked with green and blue space data through the SAIL Databank, the study found that spending time in nature was associated with higher wellbeing.

Contrary to expectations, higher greenness in residential areas was linked to lower wellbeing. However, any time spent in nature was associated with increased wellbeing. Additionally, spending time in nature was found to reduce socioeconomic inequalities in wellbeing, supporting the idea that enhancing access to nature could be a strategy to address such differences.

Co-Lead author Jo Garrett, European Centre for Environment and Human Health, University of Exeter, said:  “By linking data from the National Survey for Wales with green and blue space data through the SAIL Databank, we explored the accessibility to natural environments and how much time people spend in them.

Our study revealed a significant link between time spent in nature and wellbeing, particularly for those facing material deprivation. This underscores the critical role of accessible green and blue spaces in promoting mental health, offering actionable insights for policymakers and urban planners striving to create healthier environments for all.

Further research is needed to understand the specific characteristics of these spaces that provide wellbeing benefits, informing efforts to expand their accessibility for a wider population.”

A second study was recently published in Nature’s Journal of Exposure Science and Environmental Epidemiology, and evaluated the effectiveness of the Enhanced Vegetation Index (EVI), a satellite-derived metric, to measure access to various green spaces for use in epidemiological studies.

Using data from 1.4 million households in Wales, the study found that EVI is not able to distinguish between publicly accessible and private green spaces.

Lead author, Amy Mizen, ENVHE Researcher based in Population Data Science at Swansea University, said: “Using satellite images, our team calculated EVI for 1.4 million Welsh households in 2018. We looked at a 300-meter radius round each home.

We used linear regression models to establish whether EVI can be used to discriminate between publicly accessible and private green space, while Pearson correlation assessed associations between EVI and various green space types.

Our study highlights the challenges in using EVI for precise assessment of different green space types, emphasising the need for caution, as a higher EVI score does not necessarily indicate greater access to publicly available green spaces. Our findings suggest that when exploring the impact of green space exposure on health outcomes, especially those relying on green space use, satellite-derived measures should be accompanied with alternative data sources to more accurately characterise green spaces.”

Another key piece of research was published in the International Journal of Epidemiology in April 2022, The Green and Blue Spaces e-cohort aimed to investigate the impact of natural environments on mental health and wellbeing in Wales.

The cohort comprised of 2.8 million UK adults and investigated associations between types, proximity, quantity, and qualities of green and blue spaces and changes in mental health and wellbeing.

Lead author Daniel Thompson, ENVHE Researcher based in Population Data Science at Swansea University, said: “Utilising a cohort-based approach allowed us to anonymously “track” individuals over extended periods, providing valuable insights into the long-term impact of various factors. Our rigorous statistical analyses ensured the reliability of the findings, making the study a robust foundation for subsequent research”.

Ambient greenness, access to local green spaces and subsequent mental health were the subjects of a study published in the Lancet Public Health in October 2023. This research investigated the impact of living in or moving to areas with more green spaces or better access to green and blue spaces (GBS) on adult mental health over time.

Based on a cohort of over 2.3 million people in Wales, the study found that increased exposure to ambient greenness over time was associated with a lower risk of common mental health disorders

Rebecca Geary, University of Liverpool and lead author, said: “Our environmental health equity evidence shows the importance of enhancing our built environments by including appropriate green and blue spaces to improve the health and wellbeing of all adults, especially those living in the most deprived areas. Providing urban green and blue spaces may also give additional co-benefits of job or food creation, biodiversity promotion, flood prevention and carbon sequestration, so are both a public health and social investment.”

This NIHR report, published in the NIHR Journals Library in October 2023, summed up the Green and Blue Spaces Project and aimed to understand the connection between living near or visiting green and blue spaces (natural environments like parks and riversides) and mental health.

The study found that people in greener and bluer areas were less likely to seek help for common mental health disorders. Individuals, especially those in deprived areas, who used these spaces for leisure had better wellbeing and were less likely to seek help for mental health issues. While the study did not find strong evidence that changes in green and blue spaces affected mental health, providing such spaces could be a valuable strategy for improving mental health, especially in disadvantaged communities.

Sue Williams, Senior Social Researcher at Cyfoeth Naturiol Cymru/Natural Resources Wales, said of the report: “Working in partnership with researchers has helped bring together academic excellence with expertise from policy and practice. This increases the impact and uptake of evidence and ensures that the findings from this work can help us improve and support the value of green and blue space for mental health and wellbeing in Wales.”

Summing up on the achievements of the Green and Blue Project, Sue added: “It has been extremely rewarding to be part of this collaborative Project. The research findings from across the Project highlight the need for evidence-based policies that prioritise and conserve green and blue spaces, paving the way for a healthier and more equitable future.”

For more information, read the full NIHR Report here.  Green blue space exposure changes and impact on individual-level well-being and mental health: a population-wide dynamic longitudinal panel study with linked survey data

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