If you're exercising during an air quality advisory, you might not feel the effects right away. Omar Dabaghi-Pacheco asks a respirologist what bad air does to our bodies.

Ottawa

As air quality declines due to wildfires and pollution, outdoor exercise is becoming riskier for many people. Lung specialist Dr. Sean Aaron explains that during physical activity, people breathe in significantly more air—and thus more pollutants—than when at rest. The most concerning pollutant is PM 2.5, a tiny particle that can penetrate deep into the lungs and enter the bloodstream, leading to inflammation and increased risk of heart attacks, strokes, and chronic lung disease.

The health risks from exposure to poor air quality can persist for days and accumulate over time, potentially shortening lifespan and increasing the likelihood of chronic diseases. Research indicates that exercising in polluted air can be as harmful as smoking several cigarettes in a day, with long-term effects that may not be immediately noticeable.

Working out in smoke or smog? Here's what that does long-term

Wildfires, pollution, smog, it's all making it a lot more difficult to breathe in some clean air. And if you're like me, love being outside, love working up a sweat, but it's getting harder and harder to know where that threshold is between getting a healthy benefit from working out or doing some real long-term damage to your lungs. Air quality is part of the daily forecast, and it's something that you notice if you're out there exercising in it. I feel it in my lungs every time, like when I go on the walks. You can smell like the fire, and it just hurts sometimes. Yeah, when I go on walks, like after maybe like a good 30 minutes, I kind of start feeling it in my lungs. As long like, as soon as it gets in my face and like I can barely see anything, or it's just like unbearable, then yeah, that's where I cut it out completely. So I hit the road to track down one of the foremost experts in what happens inside your body when you're working out in bad air. My name is Sean Aaron. I'm a physician. I'm actually a lung specialist at the Ottawa Hospital and a professor at the University of Ottawa. Also a guy who loves to kayak and spend hours outdoors when it's safe, but it's not always clear when it is. Take this month's Ironman Canada, for example. Air quality index at five, or moderate risk. From a researcher's perspective? It's not the healthiest behaviour. The level of particulate matter in the air is going to be high. And the particular matter we're most concerned about is something called PM 2.5. And that is a 2.5 micron diameter particle that is easily breathed into the lungs, and which goes all the way down into your bloodstream once it gets into the lungs and can cause a lot of bad health effects. We're on this kayak for a reason. He's going to explain what happens inside our bodies in real time. OK, so as you can see, I'm paddling hard with my muscles. The muscles are triggering sensors to my brain, telling my brain, you need to breathe heavy, you need to breathe harder, and you need to breathe faster to get more oxygen down to the muscles. We're taking in 7.2 litres of air every minute we breathe. But when you're exercising, you can quadruple that rate of minute ventilation. So instead of taking 7 litres per minute, you might be taking 30 litres a minute of air in. Now, you can imagine if the air quality is poor, that means you're taking in four or five times the amount of poor air and particulate matter than you otherwise would if you were just breathing quietly. Microparticles of smoke, soot, mold, and bacteria, tiny enough to get deep into your lungs, and it all adds up. It's an inflammatory particle. And so what it does is it causes damage to the lining of the blood vessels, and it causes clotting in the blood vessels, which can lead to heart attacks and strokes, and also pulmonary emboli and deep vein thrombosis. And those long-term risks can persist for a week after you've been exposed to a bad air quality day. And that's all cumulative. So down the road, you're just kind of setting yourself up for a shorter lifespan? Shorter lifespan and more chronic diseases, especially chronic lung and chronic pulmonary disease. So when it comes to bad air quality, any amount of it in your lungs is really bad news. But research shows that exercising in the middle of it, it can be kind of like smoking a few cigarettes for that day. You might not feel the effects right away, but what it's doing to your lungs might show up in the longer term in a really bad way. Omar Dabaghi-Pacheco, CBC News, Ottawa.

All Air Canada planes were grounded on Monday (August 18) after its 10,000 flight attendants refused a return-to-work mandate from the Canadian government.

Toronto

Air Canada delays plans to resume operations

Ukrainian President Volodymyr Zelenskyy arrived at the White House Monday (August 18) for his meeting with President Donald Trump and other European leaders about Russia's war in Ukraine. CBS News White House reporter Taurean Small has more.

Washington

Ukraine Invasion

Trump meeting with Zelenskiy, European leaders at White House

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Jerusalem

Middle East Conflict

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East Coast of the United States

Erin expected to bring dangerous conditions to U.S. East Coast

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Kyiv

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Paris

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Tel Aviv-Yafo

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Anchorage

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San Juan

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Hurricane Erin strengthens in the Atlantic

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London

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Breakdown