Green spaces and bodies of water improve mental wellbeing, study finds

Giving people access to green or blue space can improve their mental health, new research has found.

Green space is defined as an area of trees or vegetation designated for people’s use in an urban environment, such as a park, while blue space refers to rivers, lakes and the sea.

The study by University of Liverpool researchers, published in The Lancet Planetary Health, found that the further people live away from green or blue spaces, the more likely they are to experience anxiety or depression. The beneficial effects of green and blue spaces appeared to be greater in more deprived areas.

The study team looked at GP records from more than two million adults in Wales over a 10-year period, January 2008 to October 2019.  The dataset was derived from the Welsh Demographic Service Dataset and consisted of anonymised individual-level demographic characteristics of citizens registered with the NHS and GPs. This dataset makes up 80% of the total Welsh population. Geographical location was provided by participants and updated when a participant or GP reported a change in household residency.

Health inequalities taken into account

This demographic data was linked to GP records, including reports of common mental health disorders (CMD), such as anxiety or depression. Data from the Annual District Death Extract from the Office for National Statistics mortality register was used to periodically add individuals who had attained the age of adulthood and remove those who had died from the dataset. The Welsh Index of Multiple Deprivation and rural-urban Office for National Statistics classifications for Lower Layer Super Output Areas were used for the socioeconomic and demographic classification of study cohort participants.

The researchers analysed the effect of accrued household ambient greenness and availability of green and blue spaces over time on subsequent adult mental health. They took into account health inequalities by anonymously tracking individuals over time and allocating exposures to green and blue spaces at the more granular household, rather than small-area, level. If a family moved house from an area near green or blue space to one that wasn’t near (or vice versa), the study was able to take account of that.

“Many previous studies,” the authors note, “measured green space exposure across small areas at a single time point, assuming the amount of vegetation did not vary within these areas or change through time.”

They found that “exposure to greater ambient greenness over time… was associated with lower odds of subsequent CMD where CMD was based on a combination of current diagnoses or symptoms (treated or untreated in the preceding 1-year period), or treatments.”

The findings also showed that individuals’ CMD history altered the benefits of ambient greenness and access to green and blue spaces. Individuals with a previous history of CMD were found to benefit more than those without prior CMD diagnoses. However, both showed positive associations, indicating that access to green and blue spaces can both help prevent and help people recover from mental illness.

A public health and social investment

The authors write that their findings demonstrate the public policy benefits of investing in green and blue spaces: “Our results suggest that investing in improved ambient greenness, as well as making public GBS [green and blue spaces] accessible, might lead to future mental health benefits for adults with and without a history of CMD. There might also be additional co-benefits: job or food creation, biodiversity promotion, and flood prevention or carbon sequestration.”

They add that urban green and blue spaces “can therefore be thought of as a public health and social investment, providing a chance to rebalance our relationship with nature, to help address our climate change challenges, and to protect against the mental health challenges of future pandemics.”

“This brilliant study gives us three reasons to be cheerful,” said Richard Mitchell, a professor of health and environment at the University of Glasgow. “First, it confirms that natural environments around us really do benefit our mental health.

“Second, the benefits seem strongest for those most at risk, so there’s huge potential for tackling the gulf in health between richer and poorer people. Third, the study shows what great science we can do in the UK using our world-leading health datasets safely and securely.”