What is asthma?

Asthma is a long-term (chronic) lung disease. The airways react to triggers (allergens
and irritants). This makes it hard to breathe. With exposure to triggers, these changes

  • The
    airways become swollen and inflamed.
  • The
    muscles around the airways tighten.
  • More mucus is made. This leads to mucus plugs.

of these changes make the airways narrow. This makes it hard for air to go out of the
lungs. And fresh oxygen can’t get into the body.

What causes asthma?

Experts don’t know the exact cause of asthma. They believe it is partly inherited. The
environment, infections, and chemicals released by the body also play a role.

Exercise causes symptoms in many people with asthma. Symptoms can occur during
exercise. They can also occur right after exercise. In some people, stress or strong
feelings can cause symptoms.

of these may be asthma triggers:


Respiratory problem

  • Pollens (trees, grasses, and weeds)
  • Mold
  • Pets
  • Dust and dust mites
  • Cockroaches
  • Mice
  • Nasal allergies
  • Sinus infections
  • The flu
  • Viral infections, including the common cold



  • Strong odors from perfumes, cleaners,
    cooking, paints, and varnishes
  • Chemicals (gases, fumes)
  • Air pollution
  • Changing weather (temperature, barometric
    pressure, humidity, and strong winds)
  • Smoke (tobacco-inhaled or secondhand)
  • Aspirin
  • NSAIDs (nonsteroidal anti-inflammatory
    drugs) such as ibuprofen

Other conditions

  • GERD (gastroesophageal reflux)
  • Sleep apnea
  • Overweight
  • Depression


  • Exercise, especially in cold weather
  • Strong feelings that go along with laughing
    or crying

Who is at risk for asthma?

is most common in:

  • Children and teens ages 5 to17
  • People living in cities

Other factors include:

  • Personal or family history of asthma or allergies
  • Exposure to secondhand tobacco smoke
  • Children with a family history of asthma
  • Children who have allergies or atopic dermatitis
  • Children exposed to secondhand and tobacco smoke

What are the symptoms of asthma?

Symptoms include:

  • Trouble breathing or shortness of breath
  • Chest
  • Wheezing or a whistling sound when breathing
  • Coughing
  • Breathing becomes harder and may hurt
  • Talking
    and sleeping may be harder with severe symptoms

How is asthma diagnosed?

healthcare provider will ask about your health history. He or she will give you a
physical exam. You will also have other tests. An important test is spirometry.

spirometer is a device used to find out how well the lungs are working. It measures the
amount and speed of air breathed out.

may have other tests. These are done to check for conditions such as allergies.