Asthma is an inflammatory disease of the airways to the lungs. It makes breathing difficult and can make some physical activities difficult or even impossible. According to the Centers for Disease Control and Prevention (CDC), approximately 27 million AmericansTrusted Source have asthma. It’s the most common chronic condition among American children: 1 child out of every 12Trusted Source has asthma. To understand asthma, you need to understand a little about what happens when you breathe. Normally, with every breath you take, air goes through your nose and down into your throat, into your airways, eventually making it to your lungs. There are lots of small air passages in your lungs that help deliver oxygen from the air into your bloodstream. Asthma symptoms occur when the lining of your airways swell and the muscles around them tighten. Mucus then fills the airways, further reducing the amount of air that can pass through. These conditions then bring on an asthma “attack,” the coughing and tightness in your chest that is typical of asthma.