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As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.
- Alex Hutchinson (@sweatscience)
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We all know that exercising outdoors with lots of air pollution is bad. But we also know that not exercising for the summer is pretty bad too. How do we balance the two? And is biking to work really any worse that sitting in a car in a traffic jam on the way to work? That’s the topic I tackle in the latest Jockology column in the Globe, which has just been posted:
The question
How harmful is it to exercise outside on a polluted day?
The answer
There’s no doubt that the air pollution in cities is bad for us. And exercise makes it worse, since we breathe in a greater volume of air and bypass the natural filtering of the nasal passages by inhaling through the mouth.
Exercising indoors, where the air tends be better during smoggy periods, is much healthier than slacking off for the summer.
But if you have to head outside anyway – to get to work, for example – the choice is trickier. Depending on when you go and what route you take, you may be better off running or biking to the office than sitting in rush-hour traffic. [READ ON…]
Alex, interesting article. One thing to consider regarding the studies of levels of volatile compounds in the blood is that there is nothing to indicate that the presence of those compounds is harmful. The particle explanation I buy (sends signals of inflammation), but having “elevated” levels doesn’t really mean anything. What are the thresholds that are safe, etc.? The levels in the air and what is safe in the body are two different things, I think.
Fair point, John. The most compelling evidence that Ken Chapman mentioned to me is that fact that heart attacks and other serious conditions are more frequent on high-pollution days — so clearly inhaling that pollution has bad effects. How does that relate to runners inhaling deeply? There’s no research (that I’m aware of) that clearly connects the dots. But if you’re someone who’s already at risk (older than 40, history of smoking, not that fit, previous breathing problems, or something along those lines), you know you’re already vulnerable and it’s reasonable to think that exercising will be even worse. So I think it’s just one risk factor to consider among many.