Great article from the Globe & Mail... I know I wonder about this when I bike home on a hot smoggy day.
How harmful is it to exercise outside on a polluted day?
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.
The basic problem is that sucking in a mix of gases and particles irritates our airways, which can result in coughing fits and difficulty breathing. While these are the most common and easily diagnosed symptoms, doctors now recognize that they represent just one part of the problem.
"All the blood in the body courses through the lungs to pick up oxygen," says Ken Chapman, director of the Asthma and Airway Centre at Toronto's University Health Network. "So if the lungs get inflamed, those inflammatory signals get carried throughout the body."