Mechanisms of exercise‐induced bronchoconstriction in athletes: Current perspectives and future challenges

Abstract

The evidence of exercise-induced bronchoconstriction (EIB) without asthma (EIBw A ) occurring in athletes led to speculate about different endotypes inducing respiratory symptoms within athletes. Classical postulated mechanisms for bronchial obstruction in this population include the osmotic and the thermal hypotheses. More recently, the presence of epithelial injury and inflammation in the airways of athletes was demonstrated. In addition, neuronal activation has been suggested as a potential modulator of bronchoconstriction. Investigation of these emerging mechanisms is of major importance as EIB is a significant problem for both recreational and competitive athletes and is the most common chronic condition among Olympic athletes, with obvious implications for their competing performance, health and quality of life. Hereby, we summarize the latest achievements in this area and identify the current gaps of knowledge so that future research heads toward better defining the etiologic factors and mechanisms involved in development of EIB in elite athletes as well as essential aspects to ultimately propose preventive and therapeutic measures. K E Y W O R D Sepithelial injury, neurogenic inflammation, osmotic, sports, thermal

Global prevalence of exercise‐induced bronchoconstriction in childhood: A meta‐analysis

“…The meta‐analysis of 10 studies revealed a higher mean prevalence (15%) of EIB among children and adolescent athletes than that in general population. The prevalence of EIB among athletes may vary substantially according to sport modality, intensity of effort, environmental conditions and diagnosis criteria . The athletes who play sports with a >5‐ to 8‐min effort, and/or in a dry/cold air environment, and/or in a noxious air environment (chlorine exposure, ultrafine particles, traffic air pollution), have a higher risk of EIB .…”

“…The prevalence of EIB among athletes may vary substantially according to sport modality, intensity of effort, environmental conditions and diagnosis criteria . The athletes who play sports with a >5‐ to 8‐min effort, and/or in a dry/cold air environment, and/or in a noxious air environment (chlorine exposure, ultrafine particles, traffic air pollution), have a higher risk of EIB . Unfortunately, the relatively small number of studies and wide variation in sport modalities across studies included in the review precluded the comparison of the prevalence of EIB between athletes of different sport modalities.…”

High incidence rate of asthma among elite endurance athletes: a prospective 4-year survey

“…Among the elite endurance athletes, the proportions of females were similar among skiers (46%) and orienteers (49%) (p ¼ 0.577). At baseline, a higher proportion of skiers had physician-diagnosed asthma (24% vs. 13%, p < 0.001), reported wheeze without having a cold (18% vs. 8%, p ¼ 0.002), and had more hours of training per week during the past year (median [IQR] 10 [8][9][10][11][12][13] vs. 8 [6][7][8][9][10], p < 0.001), compared to orienteers. Shortness of breath following exercise was reported by 12% of the skiers compared to 9% of the orienteers (p ¼ 0.290).…”

“…Environmental factors, such as the dry air in winter sports, also are believed to enhance the harmful effect on the airways and may increase the osmotic effect during high ventilation. In aquatic sports, chlorine compounds in swimming pools may lead to increased airway inflammation and epithelial damage due to oxidative stress (9,10).…”

The Relationship of IL-8 and IL-10 Myokines and Performance in Male Marathon Runners Presenting Exercise-Induced Bronchoconstriction

“…Water loss by evaporation in airway surfaces is associated with events that can trigger the contraction of bronchial smooth muscle, such as mast cell degranulation [5], which releases pro-inflammatory mediators that are involved in smooth muscle contractions, mucus production, and microvascular permeability, leading to airway edema and bronchoconstriction [5,6]. Furthermore, as mentioned in the review from Couto et al [7], epithelial damage can also be involved in EIB, and several studies have demonstrated increased infiltration of eosinophils, neutrophils, and/or epithelial cells associated with EIB, as well as an increase in airway inflammatory markers. More specifically, Seys et al [8] demonstrated an increased presence of damage-associated molecular patterns (DAMPS) in athletes with EIB.…”