It’s no secret that spending time surrounded by nature is not only good for our physical health, but our mental health as well. Being in nature can benefit those with depression and has been shown to reduce anxiety and improve mood. Creativity and problem-solving are enhanced in nature and a walk in the park can improve cardiovascular function.
There are so many varied benefits to embracing our natural environment. In fact, forest bathing, which involves slowing down and mindfully immersing ourselves in nature, is becoming popular around the country. Clearly many of us are aware of the benefits of being close to the land.
A 2019 study published in PNAS details results of the largest investigation of the association between green spaces and mental health. Researchers from Aarhus University in Denmark found that a childhood spent near vegetation is associated with up to a 55 percent lower risk of mental health disorders in adulthood. The study used combined decades of satellite imagery with extensive health and demographic data of the Danish population for the purpose of investigating mental health effects of growing up near greenery.
After accounting for potentially confusing factors (read here for details), the researchers found that a childhood spent near green space was associated with a lower risk of developing psychiatric illness in adulthood. Statistics ranged from between 15 percent to 55 percent, depending on the specific illness. For example, alcoholism was strongly associated with lack of green space growing up, while the risk of developing an intellectual disability was not associated with green space at all.
Kristine Engemann, the biologist who led the study, says:
“Green space seemed to have an association that was similar in strength to other known influences on mental health, like history of mental health disorders in the family, or socioeconomic status.”
An interesting finding of the study is that the effects of green space were “dosage dependent,” meaning that the more of one’s childhood spent close to greenery, the lower the risk of mental health problems in adulthood.
The study does have its limitations. Engemann explains that it is purely correlational, so we can’t definitively conclude that growing up near green space reduces the risk of mental illness. The study also doesn’t address how different kinds of green space affect mental health. Are forests more impactful than sparer park spaces? Do you need to actively use these spaces, or is simply growing up near greenery enough? These are questions that Engemann hopes future studies can answer.
And then there’s the big question. Why? What is it about growing up near trees, shrubs and grass that seems to boost resilience against developing mental health problems?
Kelly Lambert, a neuroscientist at the University of Richmond who studies the psychological effects of natural spaces, says the answer might be based on evolution. Humans evolved surrounded by green space; perhaps something about being exposed to our “native” environment has powerful physiological and psychological effects. Also, more green space might simply encourage more social interaction, exercise, or decrease air and noise pollution, all of which are known to impact mental health. Even exposure to a wider diversity of microbes in childhood could play a role. Says Lambert:
“There are a lot of potential mechanisms to follow up on, but generally I think this study is tremendously important. It suggests that something as simple as better city planning could have profound impacts on the mental health and well-being of all of us.”
As more studies confirm the benefits of being surrounded by open space, I hope that planners and developers will take the message to heart. That is, not only is green space aesthetically pleasing, it’s good for our health as well.