When you have asthma, the airways that carry air to and from your lungs are always swollen and inflamed. When you’re having an asthma attack, they become even more swollen and you can find yourself gasping for air. This is the situation for about one of every 12 people in the United States. If you're one of them, here's what you should know.

1. There's no cure for asthma. However, you can control it with proper care and medications.

2. What triggers an asthma attack is unique to you. Triggers vary from person to person. Many people are set off by contact with animal dander and breathing in pollen from trees, grasses and flowers. Cigarette smoke, direct or secondhand, is also a common trigger. It’s important that you learn your triggers and how to avoid them.

3. Most people need two types of medications. Short-term asthma medicines open your airways if you’re having an attack, and long-term medicines keep your airways from becoming permanently damaged by inflammation. You'll likely need them both.

4. Always keep your short-term medicines with you. These are called "rescue" medicines for a reason. Wherever you are, you need ready access to them in case of an attack. Also make sure you know the signs of when you’re in danger, and need to seek medical treatment right away. Have someone call 911 if you're having trouble walking or talking because you can’t breathe, or if your fingers and lips are turning blue.

5. Four symptoms could be a sign you’re having an asthma attack. Know these: chest tightness, coughing, labored breathing, and wheezing or making a whistling sound with each breath you take.

6. There are other early warning signs of an attack: Your neck itches. You have deep bags under your eyes. You’re exhausted. You snap at friends and family for no good reason. You feel nervous or edgy and can’t explain why. The "why" for all of these could be an asthma attack in the making.

7. Some people get asthma symptoms from exercise. This is called exercise-induced asthma, and symptoms usually start a few minutes after you start exercising and can last for approximately 30 minutes or so if you don’t take action. This seems to especially affect people who are sensitive to cold, dry air, or pollen, and are exercising outdoors. Your doctor may recommend that you use your inhaler before beginning to exercise. This also might be a sign that your asthma is poorly controlled, so be sure to tell your doctor.

8. Asthma can change over time. This makes it important to maintain regular contact with your doctor. If your asthma isn’t under control, you may need to take more medication. Don't do this on your own: Taking too much medication can actually make your asthma worse. On the other hand, if you've done well for months, you might be able to decrease the amount you take. Always talk with your doctor before making any changes.

9. Become an expert inhaler user. You need to learn when to use your inhaler and how to use it correctly. If you need help, ask your doctor to show you what to do.

10. Know the signs that your medicines aren’t working as well as they should. Do you have to use your rescue inhaler more than twice a week? Do you wake up at night coughing and wheezing more than twice a month? Schedule a checkup with your doctor to talk about these symptoms. It might be time for a medication change or a dosage adjustment.