Athletes who experience higher levels of air pollutants such as PM2.5 and ozone during their training sessions, run slower than expected in a race, a new study said. Published in the journal Nature, the study, ‘Impact of air pollution on running performance’, was done by Marika Cusick (Stanford University School of MedicineStanford University School of Medicine), Sebastian T Rowland (Columbia Mailman School of Public Health) and Nicholas DeFelice (Icahn School of Medicine). The findings suggest that while a rise in PM2.5 levels from 5.0 to 10.0 μg/m3 can slow down athletes by 1.5 per cent, the increase in ozone levels from 36.9 to 54.9 ppm results in a delay of 1.3 per cent in finishing the race. “Training and competing at elevated air pollution levels, even at exposures within AQI’s good-to-moderate classifications, was associated with slower race times,” the study said. “This work provides an initial characterization of the effect of air pollution on running performance and a justification for why coaches should consider approaches to reduce air pollution exposures while training.” What are the details of the study? For the research, the scientists analysed hundreds of collegiate male track & field athletes, associated with the NCAA (National Collegiate Athletic Association) which organises athletic programs of colleges and universities in the United States and Canada. The participants were exposed to daily air pollution concentrations for 21 days, including 20 training days prior to the final race and the day of the final race, which was five kilometres long. The scientists ran tests for over four years and for their final study, they identified a total of 1,104 performances at 143 races run by 334 elite male collegiate athletes from 46 different universities across the US. It was observed that experiencing higher levels of air pollutants deteriorated the athletes’ race performance. “Specifically, for PM2.5 and ozone respectively, comparing 21 days of exposure at the 80th percentile and 20th percentile, was associated with 1.5 per cent (12.8 seconds) and 1.3 per cent (11.5 seconds) increases in the average race time observed in our study”, the researchers said in the paper. They added, while these “increases” might seem quite small, in races as competitive as the NCAA Division I five kilometres championships, a “12-second increase can differentiate” between first and sixth position or separate those selected to be on the All-American team. How does air pollution impact the body while exercising? The latest research isn’t the first one to demonstrate the negative impact of air pollution on athletic performance. A 2019 study, published in the Journal of Sports Economics, found that every doubling of the AQI levels increases marathon finish times by 4.08 per cent, Forbes reported. The researchers said, “Suppose a runner takes 16,581 seconds to finish a full marathon on a day with average air quality (AQI is 102), this runner would need 20.7 more minutes to finish the 2014 Beijing Marathon during which the AQI was 289. For the best full-marathon runner (a young male runner) in our sample, the finish time was 8,301 seconds and the AQI on the race day (March 15, 2015) in that city (Wuxi) was 105. If he were to run the Beijing Marathon in 2014, a back-of-the-envelope calculation suggests that he would need 9.9 more minutes to cross the finish line.” Although the study didn’t mention the effects of any specific air pollutant, it pointed out that particulate matter (PM2.5 and PM10) might be the most dangerous. Over the years, scientists have also observed that training under even moderate air pollution can hamper the benefits of exercise. Any strenuous activity, like exercising, leads to an increase in an individual’s pulmonary tidal volume in comparison to when they are resting. This also makes breathing patterns switch from being nasal to predominantly oral, which bypasses air filtration. “With greater airflow velocity, pollutants are carried deeper into the respiratory tract, potentially diffusing into the bloodstream or inflaming the cardiovascular system”, the latest study said. Therefore, exercising in a polluted environment might severely harm the body. In a 2016 research, scientists found out that exercising in polluted urban areas could damage the lungs and lead to cardiovascular disease. They exposed 10 healthy male participants to pollution in a chamber and examined the functioning of their lungs at rest and when they were given a drug which simulates heart function during exercise. According to The Telegraph report, the volunteers’ blood circulation wasn’t impacted when resting. However, it worsened when the drug was administered. “This suggests that pollution is more harmful to lung circulation during exercise,” the lead researcher of the study told the newspaper.
