Exercise-induced bronchoconstriction describes, a transient and reversible contraction of bronchial smooth muscle after physical exertion, that may have symptoms, from very mild to severe. dyspnea, discomfort during breathing, chest tightness, wheezing, and cough. Sometimes symptoms doesn’t occur at all.
Exercise-induced bronchoconstriction previously called exercise-induced asthma, but this bronchoconstriction can be presented without asthma.
5 minute of high intensity aerobic training can be enough to induce symptoms within 15 minutes.
Symptoms can lasts from 30 min. to 90 minutes.
Occasionally, some individuals will experience a second wave (“late-phase”) of symptoms four to twelve hours after stopping exercise. Late-phase symptoms are frequently less severe and can take up to 24 hours to resolve.
People suffering from Exercise-induced bronchoconstriction may avoid exertion due to symptoms of breathlessness, cough, chest tightness, and wheezing. Exercise avoidance has been shown to increase social isolation in adolescents, and it can lead to obesity and poor health.
Exercise that exposes you to cold, dry air is more likely to cause asthma symptoms than exercise involving warm and humid air. Other triggers that can make EIB symptoms worse:
Pollution levels
High pollen counts
Exposure to other irritants, such as smoke and strong fumes
A recent cold or asthma episode
Exercise induced bronchoconstriction occurs sometimes in 90 % of people with asthma. And up to 20 % of those without asthma.
Elite athletes have an increased prevalence of 30% to 70%, especially in winter sports athletes and women.
Athletes frequently seek medical attention for respiratory symptoms. Asthma is a significant health concern, and Exercise-induced bronchospasm can indicate poor asthma control.
Diagnosis:
Clinical diagnosis by symptoms has low sensitivity and specificity, and some patients are asymptomatic.
Standardized testing for diagnosis includes direct and indirect methods and usually involves spirometry measurement of FEV1 changes from baseline expressed as a percent decrease.
Direct stimulation of smooth muscle receptors by methacholine to induce bronchoconstriction is well established. Sensitivity at predicting EIB has been reported to be 58.6% to 91.1%
Indirect testing, which is more specific for Exercise Induced Bronchospasm, can involve aerobic exercise in a controlled environment with cold, dry air as these conditions are known to precipitate EIB in susceptible individuals.
Treatment:
Most people with exercise-induced bronchoconstriction can continue to exercise and remain active by treating the symptoms with asthma medications and taking preventive measures.
Exercise has paradoxically been shown to improve Exercise Induced Bronchospasm severity, pulmonary function, and reduce airway inflammation in people with asthma and Exercise Induced Bronchospasm.
First line Treatment: inhaled short-acting beta 2 agonists before exercise, also called SABA, If symptoms are not well controlled with the SABA or patient is using SABA daily, additional medications can be added.
So second line treatment is daily inhaled corticosteroids (ICS). inhaled corticosteroids may take 2 to 4 weeks for the maximal benefit. This corticosteroids, appears to be more effective in patients with underlying asthma and are dose-dependent. ICS is not effective when used intermittently before exercise. ICS has multiple well-studied benefits in patients with asthma, including a reduction in mortality.
Also, daily leukotriene receptor antagonist is effective to control exercise induced bronchoconstriction, it may take 2-4 weeks for the maximal benefit. leukotriene receptor antagonist, including montelukast, zafirlukast, and zileuton, provide longer-lasting bronchodilation and are not associated with tolerance.
Also high-quality evidence exists for adding mast cell stabilizer (MCSA) before exercise.
An antihistamine may be beneficial in patients with underlying allergies.
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