DS11 has cough variant asthma and his attacks are coughing fits. He uses his rescue inhaler(XOPENEX) before games and practices, he has never had an attack during a game and he plays football, basketball and baseball. He did have an attack during football practice, the coach who I had long conversations about what DS's asthma attacks look like, ran to the medical bag, got the inhaler and DS was almost isntantly fine. He sat him out of practice and 10 minutes later he was doing drills and was fine, and believe me football drills are brutal.
DS also had a time when he did have some wheezing and was put on steriods, we asked if he needed to miss his baseball games, Dr said no, he asked that he play outfield and that they put in a pinch runner for him. DH was one of the coaches so this was no problem.
His Dr encourages excersise and sports.
Now I certainly think it depends on the asthma plan that the parents and the Drs have set forth, I am sure each person is very unique in their severity when it comes to asthma.