Exercise-Induced Allergic Reactions

Reviewed/Revised Oct 2024
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What are exercise-induced allergic reactions?

An allergy is when your body's immune system reacts to something by mistake, such as harmless food, plants, or medicine. In exercise-induced allergic reactions, the immune system reacts to physical activity, either during or after activity.

  • Asthma is the most common exercise-induced allergic reaction and is treated with typical asthma medicines

  • Becoming more fit or gradually increasing how much you exercise can prevent exercise-induced allergic reactions

What happens during an exercise-induced allergic reaction?

Exercising can trigger:

  • An asthma attack, in which your chest feels tight, you cough, wheeze, and have trouble breathing—this is more likely to occur when the air is cold and dry

  • An anaphylactic reaction—this is rare, but hard exercise can cause a severe, life-threatening reaction in which you have difficulty breathing or your blood pressure falls, leading to dizziness and collapse

Sometimes an anaphylactic reaction is caused by eating certain foods, especially wheat or shrimp, before exercising.

How do doctors tell if I have an exercise-induced allergic reaction?

Doctors will have you do an exercise challenge test:

  • Doctors measure how much air you can exhale before and after exercising on a stationary bike or treadmill

How do doctors treat exercise-induced allergic reactions?

Doctors will have you:

  • Take medicine about 15 minutes prior to starting exercise

  • Take asthma medicine, if you have asthma

  • If you had an anaphylactic reaction, avoid whatever triggered it

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