Exercise-induced bronchoconstriction in elite or endurance athletes: Pathogenesis and diagnostic considerations

Objective: To review the pathogenesis and evaluation of exercise-induced bronchoconstriction pertaining to the elite or endurance athlete, as well as propose a diagnostic algorithm based on the current literature. Data Sources: Studies were identified using Ovid MEDLINE and reference lists of key articles. Study Selections: Randomized controlled trials were selected when available. Systematic reviews and metaanalyses of peer-reviewed literature were included, as were retrospective studies and observational studies of clinical interest. Results: Exercise-induced bronchoconstriction (EIB) is the physiologic entity in which exercise induces acute narrowing of the airways and occurs in patients both with and without asthma. It may present with or without respiratory symptoms, and the underlying cause is likely attributable to environment stressors to the airway encountered during exercise. These include the osmotic effects of inhaled dry air, temperature variations, autonomic nervous system dysregulation, sensory nerve reactivity, and airway epithelial injury. Deposition of allergens, particulate matter, and gaseous pollutants into the airway also contribute. Elite and endurance athletes are exposed to these stressors more frequently and in greater duration than the general population. Conclusion: A greater awareness of EIB among elite and endurance athletes is needed, and a thorough evaluation should be performed if EIB is suspected in this population. We propose an algorithm to aid in this evaluation. Symptoms should not be solely relied on for diagnosis but should be taken into the context of bronchoprovocative challenges, which should replicate the competitive environment as closely as possible. Further research is needed to validate these tests' predictive values. (C) 2020 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.