A runner jogging along Toronto’s waterfront as wildfire smoke rolls into the city on June 6.Sammy Kogan/The Globe and Mail
A few years ago, researchers crunched data on air quality in counties where Major League Baseball and National Football League teams play. Sure enough, fielders racked up more errors and quarterbacks threw more interceptions when playing in dirty air.
As air quality worsens and wildfires once again sweep across Canada, we hear a lot about the long-term health effects of air pollution: inflammation, airway irritation and other issues that can lead to heart, lung and other ailments. For athletes, whose heavy breathing gives them a bigger dose of pollutants, problems show up more immediately, forcing them to grapple with difficult decisions about how and when to modify or cancel workouts and competitions.
Opinion: We have to learn to live with wildfire smoke
A recent review in Current Sports Medicine Reports sifts through the evidence on how air pollution interacts with exercise, and how best to minimize its effects. The study was led by U.S. Navy researcher Keifer Walsh and includes contributors from several other institutions, including environmental physiologist Michael Koehle of the University of British Columbia.
Here are five strategies they suggest for getting in your workout when the air is bad:
Avoid it
By far the best option is to avoid bad air entirely. Traffic is a major source of pollution, and sunlight triggers a rise in ozone levels, so early mornings before rush hour tend to see the cleanest air. Unfortunately, wildfire smoke doesn’t follow this pattern.
Pollutant levels drop exponentially as you move away from major roadways, so side streets, parks, or recreational paths that don’t run directly along highways are your best bet for avoiding traffic-related pollution.
Shifting your workout indoors is another alternative – as long as the air is clean and properly ventilated. That’s a good bet in newer buildings but not a given, with potential effects illustrated in recent research: a 2023 study found that competitive chess players made 26.3 per cent more errors for every increase of 10 micrograms per cubic metre of fine particulate matter in indoor air.
Go shorter and harder
Breathing heavily during a workout makes you suck in up to four times as much pollution as you would at rest. But that doesn’t mean that pushing harder is always worse, because the patterns of airflow in your lung may affect how the pollution is absorbed into your body. Previous research by Koehle and others found that the effects of vigorous exercise in polluted air are no worse than moderate exercise.
On the other hand, the longer you’re out there, the greater your exposure will be. This suggests that if you want to exercise outdoors on a day when the air quality is iffy, you’re better off pushing a little harder than staying out longer.
Mask up
The evidence for the anti-pollution effects of N95 masks isn’t as clear as you might think, primarily because there hasn’t been much research on the topic. Still, logic suggests that they could help reduce the dose of particulates.
For vigorous exercise, properly fitting masks can feel hot and uncomfortable, but Walsh and his colleagues suggest that they might be particularly useful before a competition or workout.
A masked-up biker in Toronto on Monday.Carlos Osorio/Reuters
Pop pills
Oxidative stress triggered by irritants such as ozone contribute to some of the negative effects of air pollution. To combat this, some experts have suggested taking antioxidants may help.
There’s a smattering of inconsistent and sometimes contradictory evidence for this claim – just enough to convince the Canadian Academy of Sport and Exercise Medicine and the Canadian Society for Exercise Physiology to endorse the idea of athletes taking vitamins C, E and beta-carotene for a week or more leading up to competitions in places with high ozone levels.
Get used to it
Now we’re getting to the truly controversial ideas. There are a few studies, both lab-based and in the real world, suggesting that if you train in air with high ozone levels, you’ll eventually be able to compete better in similarly polluted air. For example, an analysis of 85,000 college track athletes found that those who had been exposed to high ozone levels a week before a competition were better handled elevated levels in the meet itself.
If you’re a professional athlete, file this away as one of the unpalatable sacrifices you might choose to make in your relentless climb to the top.
For the rest of us, let this idea of “acclimating” to pollution serve as a cautionary tale. When your phone buzzes with an air quality warning that threatens to derail your workout plans for the day, it’s incredibly frustrating. Maybe you can adapt, using one of the strategies above – but if not, a rest day is probably better than a “getting used to pollution” day.
Alex Hutchinson is the author of The Explorer’s Gene: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map.
