Asthma Triggers

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What Are Asthma Triggers?

People with asthma have inflamed airways which are sensitive to things that may not bother other people. These things are “triggers.”

The most common asthma triggers include allergies, air pollution and other airborne irritants, other health conditions including respiratory infections, exercise or physical activity, weather and air temperature, strong emotions, and some medicines. 

Asthma triggers vary from person to person. Some people react to only a few while others react to many.

If you have asthma, it is important to keep track of the causes or triggers that you know make your asthma worse. Because the symptoms do not always occur right after exposure, this may take a bit of detective work. Delayed asthma episodes may occur depending on the type of trigger and how sensitive a person is to it.

Allergies (Allergic Asthma)

Substances that cause allergies (allergens) can trigger asthma. If you inhale something you are allergic to, you may experience asthma symptoms. It is best to avoid or limit contact with known allergens to decrease or prevent asthma episodes.

Common allergens that cause allergic asthma include:

Learn more about allergic asthma.

Irritants in the Air

Irritants in the environment can also bring on an asthma episode. Although people are not allergic to these items, they can bother inflamed, sensitive airways:

Learn more about air pollution and airborne irritants.

Other Health Conditions

Certain comorbid conditions can also compound the symptoms of asthma. (Comorbid means having two or more diseases at the same time.) These include:

Learn more about how other health conditions can affect your asthma.

Exercise or Physical Activity

Exercise and other activities that make you breathe harder can affect your asthma. Exercise – especially in cold air – is a frequent asthma trigger. Exercise-induced bronchoconstriction (EIB) is triggered by physical activity can can impact people with or without asthma. People used to call it exercise-induced asthma (EIA). Symptoms may not appear until after several minutes of sustained exercise. (If symptoms appear sooner than this, it usually means you need to adjust your treatment.) With proper treatment, you do not need to limit your physical activity. Exercise is important for everyone, including people with asthma!

Learn more about exercise-induced asthma.


Dry wind, cold air, or sudden changes in weather or temperature can sometimes bring on an asthma episode.

Thunderstorm asthma can also affect people with asthma if a thunderstorm hits during high pollen and high humidity. The lightning can hit pollen and break the grains into smaller pieces. Wind from the storm spreads these particles around, making it easier for people to inhale them.

Feeling and Expressing Strong Emotions

  • Anger
  • Fear
  • Excitement
  • Laughter
  • Yelling
  • Crying

When you feel strong emotions, your breathing changes – even if you don’t have asthma. It may cause wheezing or other asthma symptoms in someone with asthma.

Learn more about how strong emotions cause stress and can worsen asthma.


Some medicines can also trigger asthma, such as:

  • Aspirin and NSAIDs (nonsteroidal anti-inflammatory drugs)
  • Medicines known as beta blockers – they can also make asthma harder to control

Talk to your health care provider about your asthma and your triggers. Be sure to discuss any changes in your asthma management.

Review the list of medicines that may worsen your asthma.


Medical Review September 2015. Updated October 2019.

Asthma Care for Adults
Knowing how to manage asthma is important for better health and quality of life. We offer an online course called ASTHMA Care for Adults. This comprehensive program covers a full range of topics everyone with asthma needs to know. This self-paced online course is presented in different formats, such as videos, animations, handouts and more.

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