Updated: Apr 5, 2020
Our health isn't just the result of what we eat and how often we exercise. It's also a product of how we think and feel, and the places we live, work and play.
In fact, even the amount of green space around you - parks, trees, grass, and gardens - can have a positive impact of your physical and mental health.
The researchers suggest that more green space can have a 'protective effect' on our state of mind, as it can improve mental health and promote social engagement.
A recent US study examined the link between residential green space and mortality among women.
The study used satellite imagery to estimate a person's exposure to green space near their home. The study analysed the 8,600 deaths that occurred among the sample in this time.
The study found that the women who lived in the most 'green' areas had a 12 % lower rate of all-cause non-accidental mortality than women in the least green areas. The link was strongest for respiratory disease (34 % lower rate), cancer (13 % lower rate) and kidney disease (41 % lower rate) mortality. The researchers did not find any statistically significant differences between green space and mortality for coronary heart disease, diabetes or infections.
The researchers controlled for other mortality risk factors that might taint the results - age, race and ethnicity, smoking, and socioeconomic status. The study also accounted for changes in residence.
Why might green space affect health?
Usefully, the study also looked at potential 'mediating factors' that might help to explain how green space affects mortality. It identified four statistically significant mediators:
Social engagement (most significant). Green spaces offer a place to relax, gather, play or exercise.
Air pollution. More vegetation can contribute to better air quality and a reduction in exposure to greenhouse gases.
Physical activity (marginally significant). Green spaces might create more opportunities and incentives for physical activity.
The data suggests that all four factors combined explains 27 % of the link between green space and mortality. A big factor here is mental health, estimated to explain 30 % of the results.
Like all studies, this study has a number of limitations. One thing to keep in mind is that this study didn't look at the quality of the green space, just the quantity of green space around the home (ie, it didn't consider whether it was a beautiful park or a vacant lot).
Take home message
This study suggests that we might be able to use green space to improve the health of communities. In particular, the researchers suggest that more green space can have a 'protective effect' on our state of mind, as it can improve mental health and promote social engagement.
At the very least, it's something to ponder.
James P, Hart JE, Banay RF, Laden F. 2016. Exposure to greenness and mortality in a nationwide prospective cohort study of women. Environ Health Perspect 124:1344–1352.