Go figure

Exercise induced shortness of breath not always Asthma

Uh, could it be, I dunno, exercise?

In the study, the most common cause of exercise-induced dyspnea was simply that the patients had reached their natural limits for exercising, and their shortness of breath was an entirely normal response to vigorous exercise. Despite the varying levels of cardiovascular conditioning for the 74 patients in this group, each patient had interpreted their normal physiologic shortness of breath as being abnormal.