COMMENTARY

Diagnosing and Managing Exercise-Induced Bronchoconstriction

Nicholas Gross, MD, PhD

Disclosures

April 27, 2015

Asthma and Exercise-Induced Bronchoconstriction in Athletes

Boulet LP, O'Byrne PM
N Engl J Med. 2015;372:641-648

Study Summary

A lifelong regimen of exercise is important for maintaining health. This applies to individuals with asthma as much as it does to those without asthma.[1] Many people who indulge in intense aerobic activity have exercise-induced bronchoconstriction (EIB), a condition that is also common in elite athletes.

As an isolated symptom, EIB does not imply a diagnosis of asthma, although EIB is a common feature of asthma. EIB is the transient narrowing of the airways following exercise and is currently considered to be a distinct form of airway hyperresponsiveness. The features of EIB and current management recommendations are described in this article by Boulet and O'Byrne. The mechanism of EIB is believed to be related to the loss of water and heat from the upper airways during increased respiratory activity. Inhalation of chlorine from swimming pools or allergens and pollution in the ambient air can similarly induce bronchoconstriction.

The diagnosis of EIB with or without concomitant asthma is made on the basis of the presence of a typical symptomatology and documentation of variable airflow limitation. Spirometry or diurnal peak flow measurements support the diagnosis of asthma. Further support can be obtained by documenting a significant increase in lung function using forced expiratory volume (FEV1; an increase of 12% and 200 mL) following administration of a bronchodilator, or a corresponding decline in lung function following a bronchoprovocation challenge with methacholine. For a diagnosis of EIB, the Olympic Committee recommends the use of the eucapnic voluntary hyperpnea (EVH) test.[2]

The recommended management of asthma with EIB is detailed in the Global Initiative for Asthma (GINA) guidelines.[3] For patients with EIB but no asthma, the nonpharmacologic recommendations include use of a mask when exercising in cold conditions—for example, wearing a mask during skiing. The use of a low-intensity pre-exercise warm-up can limit EIB in more than half of cases.[4] Affected individuals should avoid activities in conditions characterized by an abundance of allergens, pollutants, and similar triggers.

Trials of pharmacotherapy for EIB are few and have not been adequately powered. For mild EIB, short-acting beta-adrenergic bronchodilators can be used either as rescue for bronchoconstriction or 5-10 minutes in advance of exercise to prevent EIB (preferred). However, if a short-acting bronchodilator is needed more than twice weekly, the recommendation is to commence a low but regular dose of an inhaled corticosteroid. An alternative would be a leukotriene modifier or, if necessary, both a steroid and a leukotriene modifier.[5] Other agents such as antihistamines, immunotherapy, and omega-3 fatty acids have not been shown to be useful in controlling EIB.[6]

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