Exercise induced asthma is a type of asthma that is experienced during strenuous exercise. The more formal term for exercised induced asthma is exercise induced broncho-constriction. This term is preferred because the exercise induces a narrowing of the airways but is not the root cause of asthma. Occupational asthma is a type of asthma that is caused by allergens in the work environment. It is caused by inhaling fumes, gasses, dust or other harmful substances.