According to a recent study, which was published in the journal The Lancet, air pollution in cities can "counter the beneficial health effects of exercise in adults over 60." The study was a collaboration between scientists from Imperial College London and Duke University.
How does exposure to air pollution affect people who exercise?
The study findings revealed that even short-term exposure to traffic exhaust on a busy street may nullify the benefits of a long, two-hour stroll, which could otherwise strengthen an older adult's heart and lungs. The researchers noted that this is the first study that detailed the negative effects of air pollution on healthy people, along with individuals who have been diagnosed with pre-existing cardio-respiratory conditions such as chronic obstructive pulmonary disease (COPD) and coronary heart disease.
Junfeng "Jim" Zhang, professor of global and environmental health at Duke, commented that data from the study contributes to the increasing body of evidence that confirms the negative cardiovascular and respiratory consequences of a quick, two-hour exposure to motor traffic pollution. Zhang added that the study findings emphasize the need for "stricter air quality limits and better traffic-control" in cities.
Fan Chung, professor of respiratory medicine and head of experimental studies medicine at the National Heart & Lung Institute at Imperial College, warned that data from these studies also highlight the fact that people can't tolerate the current levels of air pollution in city environments. (Related: City life is KILLING humanity: 95% of humans living today are breathing polluted air, mostly from cities.)
In contrast, the researchers also determined that participants who took two-hour walks in a large city park far from direct exposure to street-side traffic fumes reported notable improvements in both lung and vascular functions.
For the study, the researchers worked with 119 participants who were older than 60. The volunteers were "either healthy, had stable COPD, or stable ischemic heart disease." The participants were instructed to walk for two hours during midday at one of two London locations: either in a relatively quiet area of Hyde Park or along a busy section of Oxford Street.
The pollution on Oxford Street contains black carbon, which is produced in two ways: naturally or by human activities via the incomplete combustion of biofuels, biomass, and fossil fuels. Air pollution on Oxford Street also contains nitrogen dioxide and fine particulate matter from diesel exhaust fumes, the levels of which regularly exceed air quality limits set by the World Health Organization (WHO).
The researchers explained that physical measurements taken before and after the walks showed the effects activity had on the participants' cardiopulmonary health, such as arterial stiffness, blood flow, blood pressure, and lung capacity.
After taking a walk in Hyde Park, the lung capacity of the participants greatly improved within the first hour. For many of the volunteers, the improvement lasted for over 24 hours. Meanwhile, walking along Oxford Street only resulted in a smaller increase during the first hours, with no increase later.
Data from the study also showed that walking in Hyde Park helped minimize arterial stiffness by over 24 percent for both healthy volunteers and those with COPD, and over 19 percent for patients with heart disease. However, people who walked along Oxford Street experienced notably smaller gains.
The healthy volunteers had a maximum reduction in arterial stiffness of only 4.6 percent; COPD patients had a 16 percent reduction; and individuals with heart disease saw an 8.6 percent reduction.
The researchers commented that one of the reasons for some of the physiological differences observed between the two settings could be stress, with the "increased noise and activity of Oxford Street" affecting the study results. The team added that patients with heart disease who took medication to boost their cardiovascular health reported less severe effects after exposure to the pollution. The medication may have had a stabilizing effect.
Chung shared that many individuals, like the elderly or those who have chronic diseases, can only exercise by going on walks. He posited that, based on the study data, people should try to take walks in green spaces that are a considerable distance away from built-up areas and pollution caused by traffic. He admits that this can be harder for people who reside in inner cities, and that there could be repercussions, especially since they have to travel further away from their homes or where they work.
The researchers believe that the public needs access to urban green spaces so more people can exercise. Chung concluded, "We need to reduce pollution so that everyone can enjoy the benefits of physical activity in any urban environment."
You can read more articles with tips on how to limit your exposure to air pollution at Pollution.news.
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