Hello, I'm Dr. Phil Scott. I'm the asthma specialist who treats Sarah, Michael, and Paul. I'd like to talk with you about the medical condition of each of these athletes. I want you to understand how they should use medications to control their asthma. Let me start by giving you some general information. Asthma is a chronic inflammatory disorder characterized by episodic attacks of bronchospasm, or constriction of the bronchi (the main airways). As you can see in this illustration (click to view the respiratory system), the bronchi and bronchioles are the main airways in the lungs. In people with asthma, the muscles in the walls of these airways tighten and cause narrowing of the passages, which causes a person to have difficulty in breathing. Between asthma attacks, or episodes, the muscles relax and restore the airways to normal. Asthma is a genetic condition, meaning it runs in families, but it's also influenced by the person's environment. The inflammation in the airways makes the asthmatic sensitive to triggers such as exercise, infection, pollen, cold air, stress, and others. As you know, the three main signs of asthma are shortness of breath, coughing, and wheezing. Remember that asthma attacks are episodic, so a person's breathing can be normal between attacks.