A walk in a green park means strengthening immunity and improving mental health
Contact with nature improves physical and mental health, but not everyone has easy access to greenery
Like many people, during the worst of the coronavirus pandemic, I sought shelter outdoors, taking socially distanced walks and sitting on my deck in all weather conditions. Being outdoors reduced the chance of infection, but it also helped in other ways. “I think everyone understood that nature was the solution to many of the stress problems that people were facing,” says Jay Maddock, an experimental psychologist and director of the Center for Health and Nature at Texas A&M University. . Scientists have figured it out too. Since then, research into natural health benefits has “exploded,” Maddock says.
Spending more time in greenery lowers blood pressure, strengthens the immune system, lowers the risk of cardiovascular disease, and improves sleep. A recent study found that it may slow down the shortening of telomeres that cover chromosomes, a sign of biological aging. And there's compelling evidence that spending time in nature reduces symptoms of depression, relieves stress, and improves cognitive function.
A 2019 study of more than 19,000 people in the UK found that those who reported spending at least 120 minutes in nature (parks, forests, beaches, etc.) each week were more likely to spend less time than those who spent less time. They were also found to have higher levels of health and happiness. It didn't matter whether a person reached the total time many times little by little or whether he reached one long block. Researchers are also investigating the beneficial effects of “blue space” (water) and “brown space” (desert) on health.
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The study also highlights health inequalities created by disparities in access to green spaces, an issue that the pandemic has further spotlighted. Jennifer D. Roberts, a health equity scholar at the University of Maryland, said that low-income areas are “less likely to have trees.” It is unlikely that there will be a park of sufficient area and quality. A recent study found that formerly redlined neighborhoods (the now-outlawed practice of deeming certain areas “unsafe” for investment) are less likely to be redlined than similar areas that are not redlined. It is said that there is currently less green space compared to the demographic area.
Marcia P. Jimenez, an epidemiologist at the Boston University School of Public Health, said access to parks and other green spaces is associated with health disparities that cannot be explained solely by factors such as race, ethnicity, and socioeconomic status. Point out. “There are higher-level determinants of health: access to food, exposure to air pollution, noise, green space, and the socio-economic status of the neighborhood.” Research is beginning to show that disadvantaged groups tend to have better relative health outcomes than disadvantaged groups. “If we can increase the availability of these vulnerable populations, we can essentially address health inequalities. Start here,” says Jimenez.
In some studies, scientists use Google Street View data and satellite imagery to quantify the density and health of plants within land areas to get more accurate measurements of an area's greenness. We use something called the Normalized Difference Vegetation Index. A Bend, Oregon-based company called Nature-Quant recently developed NatureScore using machine learning. NatureScore combines multiple datasets on parks, tree canopies, air, noise, and light pollution to create a 0-100 score proxy. How green is every address in the United States (mostly urban environments typically have a score below 30, and forests have a score above 70).
In a 2024 study, Maddock and his colleagues used NatureScore for the first time to specifically analyze health outcomes for mental health. They examined the utilization of outpatient mental health services, primarily targeting depression, anxiety, and stress, across his 1,169 ZIP codes in Texas. After adjusting for demographic and socio-economic factors, they found that areas with NatureScores above 60 had approximately 50 percent lower utilization of mental health services. In 2022, Jimenez and her colleagues published a paper. JAMA Open Network Using data from the long-term Nurses' Health Study II, living in areas with more green space is associated with higher overall cognitive and psychomotor speed and attention scores. I showed that. This difference may be partially explained by fewer depressive symptoms.
There are several possible explanations for these findings. One theory holds that nature provides a respite from the mental fatigue of modern life and the built environment, thereby restoring attentional resources. A 2024 experiment involving nearly 100 participants supports this idea. Researchers found that a 40-minute walk in nature improved the ability to coordinate higher cognitive functions such as problem solving and multitasking compared to a 40-minute walk. I walked around the urban environment.
A second theory suggests that time spent in nature activates the parasympathetic nervous system, reducing the body's stress response. Studies have shown that after exposure to green, cortisol levels, which are part of that response, decrease. Additionally, green spaces indirectly impact health, as time spent outdoors promotes physical activity and provides opportunities for social connection, both of which improve mental and physical well-being.
Although Jimenez and Maddock's research is aimed at policymakers rather than individuals, it does remind us of the importance of seeking out green space no matter where we live. I recently downloaded the NatureDose app, another product from Nature-Quant. It allows you to track your time in ways other than counting steps. And we should all try to heed the advice Jimenez gives his students. “You can see how stressed they are, especially during exams,” she says. “I tell them, 'Go for a walk.'”
This is an opinion and analysis article and the views expressed by the author are not necessarily those of the author. scientific american.
