A new European study finds that physical activity is tied to better lung function among smokers, regardless of air pollution levels.
Among non-smokers, however, the findings are less clear, and some of the data suggests that exercise benefits may be reduced among never-smokers living in cities with high levels of air pollution.
The study is published in the journal Environment International.
“Many forms of physical activity occur outdoors, such as cycling, walking or running, and active transport is promoted as a method to reduce both air pollution levels and sedentary lifestyle,” says Judith Garcia-Aymerich, senior author and head of the Non-Communicable Diseases and Environment Programme at the Barcelona Institute of Global Health (ISGlobal).
“Thus, understanding the relationship between air pollution, physical activity and lung function is essential for decision making in the fields of public health and urban planning.”
The research, which involved more than 4,500 people from nine European countries, was led by ISGlobal. The study was conducted as part of the “Ageing Lungs in European Cohorts” (ALEC) project, coordinated by Imperial College London in the U.K.
An earlier study from the same project found that regular physical activity was linked to better lung function among smokers, but exposure to air pollution was not analyzed.
The new study investigated whether residential exposure to air pollution — estimated as the annual average concentration of nitrogen dioxide (NO2) and particulate matter PM2.5 and PM10 — alters the effect of physical activity on lung function, both in current smokers and in people with no history of smoking.
The researchers looked at data from 2,801 non-smokers and 1,719 smokers from nine European countries: Belgium, France, Germany, Italy, Norway, Spain, Sweden, Switzerland and the United Kingdom.
The participants (ages 27 to 57 at the study’s onset) were followed for 10 years. During this time, they were classified as being active if they exercised at least one hour two or more times a week. Pulmonary function was assessed using spirometry, a lung assessment test which measures how much air a person inhales and exhales and how quickly the air is exhaled.
The study findings show that regular physical activity is associated with higher levels of lung function among current smokers, regardless of air pollution levels. Among never-smokers, physical activity appears to have benefits for lung function in areas with low or medium levels of air pollution, but the results are less clear in more polluted urban areas.
First author Elaine Fuertes emphasizes that “the results reinforce the message that physical activity is beneficial for health, including respiratory health.”
“However, our data suggest that the benefits of physical activity may be reduced among non-smokers living in cities with high air pollution levels. If confirmed, this means that policies aimed at controlling air quality levels would maximise the benefit of physical activity promotion policies,” Fuertes says.