The effects of urban green spaces and blue skies on heart health

Proximity to and increased exposure to urban green and blue spaces (water areas) is associated with lower odds of developing coronary artery calcification, an early marker of cardiovascular disease, in midlife, according to a new study from Northwestern University.

This association was more pronounced among black individuals and those living in areas of lower socioeconomic status, with the strongest effects observed among black individuals in economically disadvantaged areas.

“The protective effect of access to urban open sky and green space with coronary artery calcification uncovered in our study highlights the potential benefits of such infrastructure, particularly for underserved populations at high risk for cardiovascular disease,” said corresponding author Hou Li-Fan, PhD, professor of preventive medicine at Northwestern University Feinberg School of Medicine. “Our findings provide quantitative evidence to support environmental policies that increase access to and quality of open sky and green space in residential areas, which can benefit public health and address health disparities associated with race and neighborhood.”

What are Green Spaces and Blue Spaces?

These are the natural environments that surround residential areas: examples of blue spaces include rivers and coastlines, and examples of green spaces include parks and forests.

What is Coronary Artery Calcification (CAC)?

Coronary artery calcification (CAC) is a buildup of calcium in plaque in the walls of your coronary arteries. It can be a sign of early coronary artery disease that can lead to a heart attack.

How was this study conducted?

This study Circulation The study, which began June 27, included 2,960 black and white men and women (average age 50) from Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; and Oakland, California, who were followed for 25 years. Researchers looked at the relationship between blue and green space and CAC by race and neighborhood socioeconomic status.

What was the outcome?

Black participants with the greatest access to a river had a 32% lower odds of coronary artery calcification compared with those with the least access. Black participants who had greater access to green space had up to 35% lower odds of calcification. For every 10% increase in green space, the odds of coronary artery calcification decreased by an average of 15%.

Why do green and blue spaces improve health?

“Increased green space and open skies may increase opportunities for physical activity, social interaction, and stress relief and recovery, all of which are linked to improved metabolic and cardiovascular health,” Hou said. “Furthermore, exposure to green space and open skies has been shown to boost immunity, reduce chronic inflammation, and slow biological aging, all of which are biologically important for overall human health and cardiovascular health. Further research is needed to fully understand the role that urban natural environments play in pathways relevant to human health.”

Do parks offer the same benefits?

The study showed that shorter distances to parks increased the odds of CAC in these areas, with those with the easiest access to parks having a 29% higher odds of CAC compared to those with the least easy access.

“Safety concerns in underserved urban neighborhoods where parks are in poor condition may discourage park use and prevent residents from fully benefiting from parks,” the study's lead author said. “From a public health perspective, the results suggest the need for quality control and management of the neighborhood environment in areas with disadvantaged social determinants of health. More data are needed to fully explain this observation,” said Kim Kiess, adjunct assistant professor of preventive medicine at Feinberg and assistant professor at Sungkyunkwan University College of Medicine in South Korea.