Even low levels of air pollution exposure lead to slower NCAA race times, study finds

March 5, 2023, 10:55 p.m.

For NCAA track athletes, a few seconds can mean the difference between winning and losing and according to a recent study, this difference may be due to a factor not often discussed in athletics — air pollution.

Researchers from Stanford, Columbia and Mount Sinai found that 5k runners competing in areas with air pollution levels that fall within the Air Quality Index (AQI)’s good-to-moderate classifications were associated with slower race times, compared to runners in areas with less air pollution. 

In the 5k, researchers found that on average, there was a 12.8 second increase in race times from 21 days of exposure to particle pollution, or PM2.5, as well as an 11.5 second increase from 21 days of ozone exposure. 88% of the exposure to PM2.5  and 70% of the ozone exposure they measured fell within API’s “good” classification.

“These findings reinforce the accumulating research indicating that even low-level air pollution can hold people back from achieving optimal performance across various domains, including athletics and cognitive ability,” said co-author Nicholas DeFelice, an assistant professor of environmental medicine and public health at the School of Medicine at Mount Sinai. 

High air pollution events, like the recent wildfires in California, have impacted many sporting events, due to smoky air conditions. However, research on the impact of lower air pollution levels on athlete’s performance has been limited, according to first author Marika Cusick.

Based on data from 46 universities across the United States, the researchers examined the performance of 334 NCAA male track and field athletes. From there, the study mapped race times with air pollution values athletes experienced prior to their races, combining 20 days of pollution exposure data at their university training location with data from the day of and day prior at the meet location. 

“From the study, we can’t really make any conclusions about the health of the athletes; it’s purely focusing on running performance,” said Cusick, who is a second-year Stanford PhD student in health policy in decision sciences. “We started looking into this because we thought it could be an interesting way for people to start caring about the fact that [air pollution] does affect athletic performance.”

For many track athletes, this study confirms what they say they’ve recognized in their sport for years. 

Based on his experience as Stanford’s Director of Track and Field and Cross Country, J.J. Clark agreed with the findings of the study. “We’ve had student athletes who were struggling with air quality in those ranges and had to stop running,” he said.

Cusick hopes that this study can help change current NCAA policies on air pollution. Currently, the NCAA states that when air pollution levels are at an AQI of 300 or above, which is the “hazardous” classification: “outdoor activities should be moved indoors or canceled if indoor activity is not an option.” However, the policies for monitoring less extreme air pollution levels are vague, stating that event coordinators should “consider” moving indoors.

“Coaches may want to consider mechanisms to try and reduce the amount of exposure that athletes are getting,” Cusick said. “Also, the NCAA may want to consider lowering the thresholds to be at more moderate levels, considering the fact that athletes are at a very high risk of inhaling pollutants even more deeply than the average person who’s just walking around.”

The researchers plan on continuing this vein of research to further learn about the health impacts of low levels of air pollution. According to DeFelice, they are building off this research by assembling a cohort of runners to understand better environmental exposures and variability in exposure between athletes’ environment and performance.

While this study only looked at male NCAA 5k runners, the researchers hope to study a more generalizable population, including women athletes and younger athletes who may be more vulnerable to the effects of air pollution, as they are still in more developmental phases of training.

“I would love to do more environmental work and think about environmental health,” Cusick said. “Right now, what doesn’t exist is monitoring air pollution levels when they’re moderate and thinking about the safety of that. Hopefully, this study will bring more awareness to that.”

Lauren is the Vol. 264 managing editor for the sports section and a Science and Technology desk editor for the news section. Previously, she was a Vol. 263 desk editor, beat reporter and columnist. You can contact her at lkoong 'at' stanforddaily.com.

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