Poor Air Quality Can Slow You Down
If you think you run slower on hazy days, then you may be on to something.
Researchers from Brown University found poor air quality on the day of a marathon is directly tied to slower race times.
by Staff Reports
Clean air is important to living a healthy life, but it's also important for peak athletic performance. Researchers from Brown University found poor air quality on the day of a marathon is directly tied to slower race times.
This was a large-scale study that tracked the times of more than 2.5 million runners from nine major marathons across the U.S. from Boston to Los Angeles between 2003 and 2019. The findings of the study were published in the journal Sports Medicine.
Scientists charted the finish times for all participants from public marathon data. That was combined with readings of fine particulate matter in the air along different points along marathon routes to create a statistical model.
"This really sophisticated spatial-temporal model of particulate matter allowed us to plot pollution at every mile of every course," study author Elvira Fleury said. "Without a model like this, it wouldn't have been possible to look at so many different marathons in different states across different years."
The research team looked at the association between pollution and finish times and found the greater the amount of fine particulate matter in the air on race day, the slower the average marathon time recorded by the runners.
While Fleury said the difference may seem small, every second matters to runners who are trying to achieve a personal record.
"Think of all the effort, time and money that a professional runner like Eliud Kipchoge put into trying to break the world record and run a marathon in less than two hours," said Fleury. "Runners at that level are thinking about their gear, their nutrition, their training, the course, even the weather. Our results show that those interested in optimizing athletic performance should consider the effect of air pollution, as well."
Fine particulate matter is characterized by air pollution particles smaller than 2.5 microns in diameter. The are generally released into the air from things such as forest fires, burning waste, vehicle emissions, industrial activities and fertilizer application.
The concentration of air pollution is measured in terms of micrograms per cubic meter of air and is expressed as µg/m3. Fleury and her fellow researchers found that each 1 µg/m3 or higher reading on race day was associated with a 32-second slower average finish time for men and a 25-second slower average finish time for women. The effects were more pronounced for the better runners.
Previous studies have shown the effects of air pollution on the general population can affect the heart and lungs. Researchers theorize the race-day pollution can affect runners by increasing blood pressure, constricting blood flow and reducing lung function.
"People who can complete a marathon are generally quite healthy, and we can assume they have honed their cardiorespiratory fitness," said fellow researcher Joseph Braun. "This study revealed a negative impact from air pollution, even at levels below current health-based standards, on these very healthy people. This means that air pollution can be a health risk not just for those who are elderly or susceptible - it can negatively affect even the most healthy and well-trained among us."