I always have a cough after really tough cardio. it's a dry cough without wheezing, and often lasts for several hours after i'm done exercising. i work out indoors, so i don't think it's from pollution. no hx of asthma.what causes this?

Cough: There is a thing called exercise induced Asthma or bronchospasm. See if it goes away with taking albuterol inhaler before exercise.

Bronchoconstriction: A dry cough associated with exercise could be related to exercise induced bronchoconstriction ( also known as exercise induced asthma). This might be related to the breathing of dry air and excessive response of the bronchial tree to it.