With widening research, doctors have even more reasons to tell patients to spend time in open spaces for better mental health.
Now, a statewide study suggests even small differences in nearness to urban green spaces and access to waterfronts have ties to improved self-reported mental health among people 65 and older.
Such proximity to open spaces appears to help seniors battle depression or mental distress, which are risk factors in cognitive decline and dementia, said researcher Adithya Vegaraju, a medical student in the Washington State University Elson S. Floyd College of Medicine.
He spent two years in Spokane and is now in the Seattle area for his fourth year of studies. Vegaraju suggested this research with mentor Solmaz Amiri, a WSU faculty member in Seattle and expert in geographic information systems.
Older people can be more vulnerable to mental health issues while less likely to receive treatment for those problems, Vegaraju said.
"Older adults with depression, anxiety or mental health issues are known to be more resistant to medical interventions or talk therapy, which are the go-to treatments for these conditions," Vegaraju said.
He said one solution might be to have health providers write nature prescriptions — a growing trend especially in Europe — to recommend that patients spend time regularly outdoors. If exposure to green spaces or bodies of water could help prevent or treat poor mental health in older adults, he said it's a topic that deserves a closer look.
Within residential ZIP code areas, the study measured the closest green spaces — parks, forested areas, city tree canopies and trails — along with what researchers called "blue spaces" that range from rivers to lakes and coastlines.
Published in the journal Health & Place, the research is based on Behavior or Risk Factors Surveillance System health survey data from more than 42,000 people 65 and older who lived in urban areas of Washington between 2011 and 2019, including in Spokane.
It linked what survey respondents reported for their general health and mental health to their proximity to green and blue spaces within ZIP codes.
"We found in a nutshell that older adults may benefit from exposure to green and blue space," Vegaraju said. "Particularly, we found the percentage of green space, or a greater percentage of green space, was associated with a lower chance or odds of having serious psychological distress."
It was similar for nearness to bodies of water, he said.
Amiri agreed. However, she said more research is needed to know how exposure to those spaces might lead to better mental and general health. She plans to study more about the links. Established research already connects the benefits of time outdoors to increased physical activity, Amiri said, and that exercise also helps reduce risks.
"It is thought that exposure to green and blue spaces could help slow cognitive decline," she said.
"We already know that physical activity decreases the chance to have dementia, so green space could potentially indirectly influence dementias," Amiri said. "Having more trees, shrubs, bushes can reduce the level of noise, so that's another component.
"We just felt like as a first step, let's look at green space exposure and mental health outcomes among older adults."
The study's findings showed that having just 10% more forest space in a person's residential ZIP code was associated with reduced serious psychological distress, or mental health problems that require treatment and interfere with daily life.
A 10% increase in green space, tree cover, bodies of water or trail length lowered the chance that older people reported their general health as poor or fair.
"Our findings suggest that loss of our urban green and blue spaces due to rapid urbanization may not just have an environmental impact but could have a public health impact, as well," Vegaraju said.
The researchers presented preliminary findings at an American Academy of Neurology Annual Meeting in April. Those findings looked only at the relationship between serious psychological distress and distance to the closest green and blue space. In a final published study, the researchers looked at additional measures, including the percentage of green space, tree canopy, forest area, length of trails and open space within ZIP codes.
Other factors include demographics, such as race and education level. Parks in some areas may be of poorer quality or hard to reach across a busy street, Amiri said.
"We are only talking about associations at this point," she said. "We know, for instance, areas of lower socioeconomic status neighborhoods can have a lower amount of green space. It's hard to prove there is a relationship, because it's also related to socioeconomic factors."