In , people's airways become so narrow (temporarily or permanently) that it's difficult for them to breathe. Asthma typically comes in episodes or "attacks” of wheezing, coughing and shortness of breath. Without proper treatment, the lungs may gradually take in less oxygen, affecting your general physical fitness.
But doesn't always get worse. Nowadays, can be treated quite effectively using medicine and other interventions such as regular exercise. Most people with can manage their illness and live a mostly symptom-free life. It's important to know what you can do on your own, and to find out what kind of treatment is best suited to you.