Run With It: Asthma and Running

Always have your bronchiodilating inhaler with you at all times and use it at the first sign of wheezing. Exercise at a low intensity in the beginning and gradually build over a period of time. Use your inhaler several minutes before exercise. It may reduce your chances of an EIA (exercise-induced asthma) attack.
Asthma-Run With It! - Road Runner Sports
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Some asthmatic runners may skip a warm-up—thinking that doing so will save their lung power for their race or workout—but, as it happens, getting your lungs working hard beforehand may actually help you avoid an attack. "There's a refractory period for bronchospasm," says Roberts. "If you do a warm-up hard enough to induce some coughing or wheezing, it usually takes about four to six hours before you have as bad a spasm again."

The key is to warm up just hard enough to get a small spasm without sapping your energy. Roberts suggests running for a few minutes, then doing several short, hard pickups (bursts of faster-paced running).

Take extra precautions if you have severe asthma. If you've ever had what Roberts calls a "flash attack," in which you quickly go from feeling good to being in severe distress, you should either run with a friend or carry your cell phone—or both.