Are the negative effects of air pollution modified among those with a more active lifestyle? A review of the literature

BackgroundLong-term exposure to air pollution is associated with a significant increased risk of morbidity and mortality, while regular physical activity is associated with decreased risk of morbidity and mortality. Air pollution concentrations are often high in major cities worldwide. As such, millions of people engage in regular physical activity in highly polluted outdoor environments. It is unclear if the adverse effects of long-term exposure to air pollutants are modified by regular physical activity.MethodsTo help understand this complex issue, we reviewed the peer-reviewed literature for studies that examined whether the impacts of air pollution exposure are modified by routine physical activity. Articles were identified through PubMed, Science Direct, ProQuest Agricultural & Environmental Science Database searches on terms encompassing air pollution and exercise/physical activity (n=334). After initial screening, 16 papers were initially included in this review. After full review, three studies did not meet the criteria for review and were excluded.ResultsMajority of studies occurred in Asia (n=5), North America (n=4), and Europe (n=3). The remaining study occurred in several countries (China, Ghana, India, Mexico, Russia, and South Africa). The ongoing review of these papers has yielded mixed results. Eight studies concluded the risks of exposure to air pollution outweigh the benefits of physical activity especially among children (n=5 studies). However, five studies concluded that regular physical activity can negate the negative impacts of long-term air pollution exposure, particularly among healthy adults (n=4 studies). ConclusionsInitial results of this review suggest sensitive groups, such as children, who are routinely physically active in areas with high air pollution levels incur more risk than benefit. Yet, regular physical activity among healthy adults may decrease the negative effects of long-term exposure to air pollution. This abstract does not necessarily reflect EPA or CDC policy.