Exercise-induced bronchospasm, often referred to as EIB, describes a temporary narrowing of the airways that occurs during or, more commonly, after physical activity. This condition can affect individuals who have underlying asthma, as well as those who do not have a chronic respiratory condition. The narrowing of the bronchial tubes makes breathing more difficult, leading to a range of respiratory discomforts.
Symptoms and Triggers
Symptoms of exercise-induced bronchospasm often emerge shortly after physical activity. These include coughing, wheezing, and shortness of breath. Many also describe chest tightness or pressure, along with unusual fatigue. These symptoms commonly appear within 5 to 10 minutes after strenuous exercise.
Several environmental factors trigger EIB episodes. Breathing cold, dry air is the most prevalent trigger, as it can irritate sensitive airways. Other elements include high pollen counts, air pollution, and airborne chemicals like chlorine fumes in swimming pools. The intensity and duration of physical activity also play a significant role in determining EIB likelihood and severity.
The Underlying Cause
EIB’s physiological basis involves a specific respiratory system reaction. During vigorous exercise, individuals often breathe more rapidly and primarily through their mouths, bypassing the natural warming and humidifying functions of the nasal passages. This increased intake of cool, dry air leads to a rapid water loss and cooling of the delicate airway lining.
This change prompts a cellular response. Specialized immune cells called mast cells, located within the airway lining, release inflammatory substances like histamines and leukotrienes. These act on the smooth muscles surrounding the airways, causing them to contract and tighten, narrowing the bronchial passages. This constriction directly leads to the characteristic symptoms of EIB, making it harder to move air in and out of the lungs. Individuals with chronic asthma often have pre-existing airway inflammation, making their airways more reactive to these triggers.
Diagnosis and Medical Evaluation
Diagnosis of exercise-induced bronchospasm begins with a review of the patient’s health history. This involves discussing symptoms, their nature, timing, and triggers. This detailed account helps the doctor understand the pattern of the individual’s respiratory responses.
The primary diagnostic tool to confirm EIB is spirometry, a test that measures lung function. Spirometry assesses how much air a person can exhale and how quickly they can do so. To identify EIB, a doctor often performs an “exercise challenge test.” During this test, spirometry is conducted before and after controlled physical activity, such as running on a treadmill or using a stationary bike, to observe a significant decrease in lung function post-exercise, indicating EIB.
Management and Prevention Strategies
Managing exercise-induced bronchospasm involves medical interventions and lifestyle adjustments. The most common medical treatment involves a short-acting rescue inhaler, such as albuterol. This medication is administered 15 to 20 minutes before physical activity, relaxing airway muscles and preventing narrowing. For frequent or severe symptoms, a doctor might prescribe daily long-term controller medications to reduce underlying airway inflammation and sensitivity.
Beyond medication, several practical strategies can help minimize EIB episodes:
- Incorporate a 10 to 15-minute warm-up period before intense exercise.
- Breathe through the nose rather than the mouth to warm and humidify incoming air.
- In cold weather, wear a scarf or mask over the mouth and nose for additional warmth and moisture.
- Choose activities with short bursts of effort rather than prolonged endurance, such as baseball, volleyball, or wrestling.
- Include a cool-down period after exercise.