Respiratory effects of running in urban areas with high and low ambient air pollution: A scoping review

Running is a popular way for people to keep fit and healthy. With the majority of people living in urban areas, this popular method for staying fit may be a double-edged sword. Running in areas of high ambient air pollution causes a higher dose of inhaled pollutants. We sought to establish the degree to which this increased dose of pollution is detrimental to respiratory health or performance and if it outweighs the benefits of running in urban areas. We conducted a scoping review of the literature using PubMed, Scopus, Embase and the Cochrane library. While there were mixed results on the effect of running in high ambient air pollution, most of the evidence indicates that it is hazardous for respiratory health. Reports of falls in lung function, inflammatory markers and impaired nasal mucociliary clearance were some of the reported significant effects in the respiratory system of runners in highly polluted areas. There were also studies that reported non-significant effects. Other secondary effects were also reported in some studies such as increased systolic blood pressure and impaired cognition. Some studies found that reduced running performance was associated with running in high ambient air pollution, while others only found a significant association in female runners. Running is a cheap and convenient way for staying fit and healthy and should be promoted to reduce the incidence of non-communicable diseases, but more greenways and parks should be provided for runners in cities to mitigate against the effects of airborne pollutants.