Greenery could increase your lifespan
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Green cities are often at the centre of the debate around climate-friendly urban planning. But greenery is not only good for mitigating CO2 emissions and their effects: New research has found that living near greenery can add up to 2.5 years to our lives.
Green spaces in cities are key to liveability. They contribute to the mitigation of climate change effects by cooling the city and helping to create a sponge effect. They are also very popular with urban populations, especially since the COVID-19 pandemic. Now, new research published in the peer-reviewed journal Science Advances suggests that long-term exposure to greenery can add years to human life. The paper adds to existing knowledge about the health benefits of living around greenery by showing how nature can affect our bodies. After studying long-term exposure to green space and its effects on biological ageing among over 900 people in four US cities, researchers concluded that being near green space causes “some biological or molecular changes that can be detected in our blood”.
Greenery can improve our biological age
Nature can quite literally get under our skin, it appears. By comparing the age-related biological changes in the study’s participants over a period of 20 years, the study authors showed that those living closer to green spaces can live longer. With the help of DNA chemical modifications called methylations, the researchers proved that greenery can cause changes in blood, which positively impact the biological age.
Over 20 years, the researchers studied 900 Black and white participants in Chicago, Oakland, Birmingham, and Minneapolis. They took blood samples after 15 years and after 20 years and compared them with the distance that individuals lived from a park or another source of greenery.
A person’s biological age and their chronological age are two different indicators of health. If the biological age is older than the chronological age, there is often a risk for developing age-related health conditions such as cancer, cardiovascular disease, or Alzheimer’s. Lifestyle choices can influence the biological age drastically. Living near green spaces in cities and frequenting them often is part of the strategy, it appears. Our biological age depends on what we do every day, for example on our food intake and physical activities.
Making healthy living decisions
With the help of satellite imaging, the researchers identified major parks and green spaces near the participants’ homes. However, this does not necessarily mean that the green spaces are accessible or of high quality. Therefore, the study can only show the impact of a given quantity of vegetation. For urban planners, it is important to know what type of greenery could improve the quality of life in their cities. More research is necessary to better understand these factors.
There are some more open questions that the study could not answer. For example, the rate of biological ageing was not the same across race, gender, and socioeconomic status. Black people with more access to green space were only about one year younger in biological age compared with the study’s average of 2.5 years. More studies will help to pinpoint how people can better benefit from greenery and what other social determinants might be important for reducing our biological age.
The researchers are hoping that their study will encourage people to think more about their surroundings in terms of healthy living decisions. In addition to diet, sleep, and exercise, time spent in urban greenery is key. By changing our perspective on green spaces and seeing them as a vital part of urban infrastructure, as something that humans require to thrive and be healthy, we can give them more importance.
Many open questions left
The study is one of the first that really demonstrates how exposure to nature can fundamentally change our biomarkers of ageing. Its researchers have expressed their hopes that urban planners will expand green infrastructure in cities to promote public health and to reduce health disparities between those living closer to greenery and those living further away.
Currently, there are many debates around the value of green space in cities. While no one will deny the inherent value of nature in the city, both for climate change and for liveability, there is a danger of neglecting other aspects of urban planning. Activities such as planning trees or creating parks should always be accompanied by other improvements, such as providing cycle lanes and pedestrian space, for example. In addition, greenery per se is not always “good”. When illicit activities take place in a park, the value for our biological age can quickly disappear.
In terms of the human lifespan, there are many other factors that can have an effect. Both physical and mental health can improve from frequenting green spaces in the city, but a healthy diet and enough exercise are at least equally important. There is still a lot of research to be done.