Exercise-induced bronchoconstriction (EIB) is a manageable condition that affects people with or without asthma. This respiratory response involves a temporary narrowing of the airways during or immediately following physical activity. While EIB symptoms can be disruptive, proper planning and treatment allow individuals to participate in exercise without limitation. Understanding the cause and having a clear management plan are the first steps to controlling this condition.
Understanding Exercise-Induced Bronchoconstriction
EIB is a narrowing of the airways that typically begins five to 20 minutes after starting exercise or shortly after stopping. Common symptoms include shortness of breath, wheezing, chest tightness, a persistent cough, and unusual fatigue.
The primary mechanism involves the rapid breathing of large volumes of air during intense physical activity. When breathing quickly, especially through the mouth, the airways are exposed to air that is often cooler and drier than the air inside the body. This rapid hyperventilation causes the cells lining the airways to lose water, leading to dehydration and an osmotic imbalance. This change triggers the release of inflammatory chemicals, causing the smooth muscle surrounding the airways to contract and narrow.
Diagnosis is confirmed through pulmonary function testing, such as spirometry, before and after a controlled exercise challenge. This test measures the forced expiratory volume in one second (FEV1); a drop of 10% or more indicates EIB. Objective testing helps rule out other causes of breathlessness during exertion.
Strategies for Preventing EIB Episodes
Preventative strategies focus on actions taken before exercise to reduce the likelihood of an airway response. Incorporating a proper warm-up routine can induce a “refractory period” that protects the airways for up to an hour or more afterward. High-intensity interval or variable intensity warm-ups are effective at attenuating the subsequent drop in lung function. This routine should include several bursts of near-maximal effort lasting a few minutes each.
Environmental controls are important for reducing the effects of inhaled air. Exercising in cold, dry conditions can be mitigated by wearing a mask or scarf over the mouth and nose to help warm and humidify the air. Individuals should also avoid outdoor activity when common triggers, like air pollution or pollen counts, are particularly high.
Short-Acting Beta Agonists (SABAs), such as albuterol, are the most common medication used for prophylaxis. When inhaled 15 to 30 minutes before starting exercise, these medications relax the muscles around the airways, preventing constriction. This pre-treatment typically provides protection for up to four hours.
Acute Treatment and Rescue Protocols
Despite preventative measures, an acute EIB episode can still occur, requiring a clear rescue protocol. The immediate step is to stop the activity as soon as symptoms like wheezing, persistent cough, or chest tightness begin. The individual should remain calm and move to a seated or upright position.
The SABA rescue inhaler is the treatment for an active episode. The medication should be taken exactly as prescribed, which typically involves two to four puffs. These quick-relief medications provide rapid relief from bronchoconstriction. Symptoms should begin to improve within five to ten minutes of the dose.
If symptoms persist or worsen after the initial rescue dose, repeat the treatment after a short waiting period, usually five to ten minutes. Seek emergency medical attention immediately if symptoms do not improve after the second set of doses. Any signs of severe respiratory distress, such as difficulty speaking in full sentences or a bluish tint to the lips or fingernails, warrant an immediate call for emergency medical services.
Long-Term Management and Control
Long-term management focuses on achieving overall control of the underlying airway hyperresponsiveness. If EIB symptoms are frequent or require SABA use more than two days a week, a daily controller medication is often needed. These maintenance therapies reduce the chronic inflammation that makes the airways sensitive to triggers.
Inhaled corticosteroids (ICS) are the primary choice for daily controller therapy, as they directly target and reduce airway inflammation. For persistent symptoms, a combination inhaler containing an ICS and a Long-Acting Beta Agonist (LABA) may be prescribed. LABAs provide sustained bronchodilation, helping to keep the airways open day-to-day.
Regular check-ups with a healthcare provider are necessary to monitor lung function and adjust medication dosage as needed. Working with a doctor to create a written asthma action plan (AAP) provides specific instructions for daily care, preventative steps, and emergency protocols. Adherence to a daily maintenance plan decreases the frequency and severity of EIB episodes over time.