Yes, it’s Global Running Day. No, you probably shouldn’t go for a run today.
The New York Road Runners canceled all its Global Running Day-related events on Wednesday as smoke from wildfires in Canada drifted over large parts of the United States. “If you’re in NYC or any affected area, please read and follow your city’s health advisory regarding air quality for June 7, and consider running another day.”
On Tuesday, the running club had already urged people not to go for a run outside, and to log their outdoor miles after the skies had cleared. This is especially true for people who suffer from chronic respiratory conditions like asthma.
A 2021 study by the European Heart Journal concluded as much, saying that an increase in exercise in a highly polluted environment “may adversely affect cardiovascular health.”
“People should avoid exercising outdoors during smoky conditions,” California’s Air Resources Board advises. “Exposure and the resulting health effects depend on the amount of time spent outside, level of exertion, level of air pollution, and possible existing health conditions.”
Smoke from wildfires includes a mix of particles. Some — like dust or smoke — are big enough to be seen with the naked eye. Others, however, are microscopic, about one-fifth to one-30th as wide as a human hair. Those tiny ones can travel deep into a person’s lungs and bloodstream. For runners, smoky conditions can also hinder visibility.
During exercise, people largely breathe through their mouths instead of their noses. The mouth — unlike the nose — doesn’t have a natural filtration system for pollutants, which means more pollutants can enter the body, according to the American Lung Association. And the ultrafine particles aren’t exhaled during exercise.
“If you’re a New Yorker with heart or breathing issues, be careful when you’re outdoors,” New York City’s mayor’s office advised. “Try to limit outdoor activities today to the absolute necessities.”
On Tuesday, New York’s air quality rating briefly ranked as the worst of any city in the world, according to the IQAir World Air Quality Index.
For competitive athletes, there may be another reason to postpone an outdoor run: Polluted areas may also cause you to run slower, a 2019 study found.
If the conditions last, several days’ worth of polluted air could have a cumulative effect, Australia’s Sports Commission said, “lowering an athlete’s threshold for symptoms.”
