Before the 2008 Olympic Games, there was concern that air pollution in Beijing would affect the performance of marathon runners. Air pollutant concentrations during marathon running and their effect on performance have not been reported. Evidence suggests that the lung function of females may be more susceptible than that of males to air pollution, but it is uncertain if this translates to decreased marathon performance.
Purpose: The purposes of this study were to 1) describe ambient air pollutant concentrations present during major US marathons, 2) quantify performance decrements associated with air pollutants, and 3) examine potential sex difference in performance related to air pollutants.
Methods: Marathon race results, weather data, and air pollutant concentrations were obtained for seven marathons for 8-28 yr. The top three male and female finishing times were compared with the course record and contrasted with air pollutant levels and wet bulb globe temperature (WBGT). A WBGT-adjusted performance decrement was calculated, and regression analysis was used to quantify performance decrements associated with pollutants.
Results: The air pollutant concentrations of carbon monoxide, ozone, particulate matter smaller than 10 microm (PM(10)), PM(2.5), nitrogen dioxide, and sulfur dioxide ranged from 0 to 5.9 ppm, from 0 to 0.07 ppm, from 4.5 to 41.0 microg x m(-3), from 2.8 to 42.0 microg x m(-3), from 0 to 0.06 ppm, and from 0 to 0.05 ppm, respectively. After adjusting for WBGT-associated performance decrements, only PM(10) was associated with decrements in performance of women. For every 10-microg x m(-3) increase in PM(10), performance can be expected to decrease by 1.4%.
Conclusions: The concentrations of air pollution present during marathons rarely exceed health-based national standards and levels known to affect lung function in laboratory situations. Regardless, PM(10) was significantly correlated with performance of women marathon runners.