Exercise-Induced Asthma

Diagnosis

Diagnosing exercise-induced asthma (also called exercise-induced bronchoconstriction) involves a detailed medical history, physical examination, and lung function tests. These help confirm the diagnosis and rule out other causes of breathing difficulty during or after exercise.

Test of current lung function

Spirometry is usually the first test performed. It measures how well your lungs are working when you’re not exercising. The test evaluates:

• How much air you can inhale and exhale.

• How quickly you can exhale air.

After the first test, your provider may give you an inhaled bronchodilator — a medicine that helps open your airways — and repeat spirometry. If your airflow improves after using the bronchodilator, it suggests asthma rather than exercise-induced asthma alone.

This step helps rule out chronic asthma as the main cause of your symptoms.

Exercise challenge tests

An exercise challenge test helps confirm the diagnosis by recreating symptoms under controlled conditions. During this test:

• You may run on a treadmill or use stationary exercise equipment to increase your breathing rate.

• The exercise is done intensely enough to potentially trigger symptoms.

• Spirometry tests are performed before and after exercise to check for airway narrowing.

In some cases, real-life challenges such as climbing stairs or outdoor running may be used to closely mimic your usual triggers.

Methacholine challenge breathing test

This test helps confirm the diagnosis when symptoms are unclear. You’ll inhale methacholine, a substance that can temporarily narrow the airways in sensitive individuals. Spirometry is then repeated to measure lung function.

If your airways react strongly to methacholine, it supports the diagnosis of exercise-induced asthma.

Spirometer

A spirometer is a diagnostic device used during lung function tests. It measures the total amount of air you can inhale and exhale and records how long it takes to exhale after a deep breath.

Treatment

Treatment for exercise-induced asthma focuses on preventing symptoms during activity and maintaining long-term control.

Preexercise medicines

Your healthcare provider may prescribe medication to take before exercise. It’s important to follow instructions carefully on how long before exercise you should use the inhaler.

• Short-acting beta agonists (SABAs):
  Medicines like albuterol (ProAir HFA, Ventolin HFA, Proventil-HFA) and levalbuterol (Xopenex HFA) are the most common preexercise treatments. These inhaled medications open the airways quickly and prevent narrowing.
  ⚠️ Avoid daily use — frequent use can make them less effective over time.

• Ipratropium (Atrovent HFA):
  An inhaled medicine that helps relax airway muscles. It can also be used via a nebulizer for some individuals.

Long-term control medicines

If preexercise medicines don’t fully control symptoms, long-term treatment may be prescribed. These are usually taken daily and aim to reduce inflammation and improve breathing over time.

• Inhaled corticosteroids:
  Help reduce airway inflammation. Full benefit may take up to four weeks of consistent use.

• Combination inhalers:
  Contain both a corticosteroid and a long-acting beta agonist (LABA) to provide ongoing control. These may also be used before exercise as directed by your provider.

• Leukotriene modifiers:
  Oral medicines that block inflammatory chemicals (leukotrienes). They can be taken daily or at least two hours before exercise.
  ⚠️ Possible side effects include mood or behavior changes and suicidal thoughts — report these immediately to your healthcare professional.

Don’t rely only on quick-relief medicines

Preexercise inhalers can help prevent symptoms, but using them too frequently may indicate poor asthma control.

Keep a record of:

• How many puffs you use each week.

• How often you use your inhaler for prevention or symptom relief.

If you find yourself using your inhaler daily or frequently for symptom control, your provider may adjust your long-term medication plan.