Green Space Boosts Health at the Cellular Level, Study Finds

Spending time in nature, whether it be deep in the wilderness, on a walk through a park or surrounded by the trees and plants in your own backyard, has been shown to have positive impacts on well-being.

A new study by an international team of researchers has found that green space — the vegetation in parks, public spaces and gardens — has a positive effect on an important genetic marker related to exposure to stress, a press release from North Carolina State University (NC State) said.

The study also found that green space’s positive impact is not enough to make up for other environmental challenges like systemic racism.

“The exposome, reflecting the range of environmental exposures individuals encounter throughout their life, can influence a variety of health outcomes and can play a role in how the environment impacts our genes,” the authors of the study wrote. “Telomeres, genetic structures regulating cell growth and senescence, are one pathway through which the exposome may impact health. Greenspace exposure, representing the amount of green areas in one’s neighborhood, is one component of the exposome and has been associated with multiple health benefits.”

Telomeres, sections of DNA at both ends of a chromosome, protect the chromosomes’ ends from damage, according to the press release. But with each division of a cell, the telomeres become slightly shorter. When the telomeres are so short the cell can no longer successfully divide, it results in cell death.

“This makes telomeres important markers of biological age, or how worn down our cells are,” said lead author of the study Scott Ogletree, who is a former postdoctoral researcher at NC State’s Center for Geospatial Analytics, in the press release. “And we know that many variables — such as stress — can influence how quickly our telomeres wear down.” Ogletree is now a professor of landscape and wellbeing at the University of Edinburgh.

The study, “The relationship between greenspace exposure and telomere length in the National Health and Nutrition Examination Survey,” was published in the journal Science of the Total Environment.

“There’s a lot of research that talks about the various ways in which greenspace is beneficial, and a lot of research that talks about adverse health effects associated with pollution, racist segregation in housing, and other social and environmental challenges,” said Aaron Hipp, co-author of the study and a professor of parks, recreation and tourism management at NC State. “This study was an attempt to quantify the beneficial impacts of greenspace at the cellular level, and the extent to which greenspace can help to offset environmental harms.”

For the study, the researchers used data from the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey (NHANES) from 1999 to 2002. NHANES is a study that uses physical examinations and interviews to assess the health of the country’s population.

The research team examined the length of the telomeres, as well as location and demographic data, for 7,827 people. The team looked at how much green space each person’s neighborhood had and its relationship to the length of their telomeres.

The team took into account potential variables like health history, lifestyle and substance use. They also pinpointed other environmental variables that had the potential to affect telomere length, like air quality and “redlining” maps used to track historically segregated neighborhoods.

“We found that the more greenspace people had in their neighborhoods, the longer their telomeres were. That was true regardless of race, economic status, whether they were drinkers or smokers, etc.,” Hipp said in the press release.

Ogletree pointed out that some circumstances were found to negate the positive effect on telomeres.

“That’s the good news,” Ogletree said. “However, when we accounted for other characteristics of each neighborhood — air pollution, segregation, or ‘deprivation’ — the positive effect of the greenspace essentially disappeared. Deprivation, in this context, was an overarching variable that included the neighborhood-level data on income, education, employment status, and housing conditions. In other words, while greenspace seems to help protect telomere length, the harm from other factors appears to offset that protection.”

While green space is essential to well-being, so is the addressing of environmental factors that are damaging to individuals and society.

“Greenspace is tremendously valuable for a community, but it is not enough to overcome systemic racism and the effects of economic segregation and environmental justice challenges on its own,” Hipp said in the press release. “This study drives home the idea that creating greenspace in a community is important, but it’s as crucial — or more crucial — for us to address environmental harms, particularly those tied to systemic racism.”