The muscles in your air tubes tighten. These changes cause the air tubes to narrow. This makes it hard to breathe. Asthma attacks may start suddenly. Or they may take a long time, even days, to develop.
Attacks can be severe, moderate or mild.
These attacks are more common. You may start to feel tight in your chest. You might start coughing or spit up mucus. You may feel restless or have trouble sleeping. You might make a wheezing or whistling sound when you breathe.