Laryngeal response to high-intensity exercise in healthy athletes

Abstract

Introduction: Exercise-induced laryngeal obstruction (EILO) is a common cause of exertional breathing problems. The current diagnostic approach rests on evaluation of laryngeal obstruction visualised by laryngoscopy performed continuously throughout a maximal exercise test (continuous laryngoscopy exercise (CLE) test) in patients who present with compatible symptoms. Laryngeal responses to high-intensity exercise in endurance athletes are not well described, potentially leading to inaccurate reference values and increasing the risk of misdiagnosing EILO.

Aim: To investigate laryngeal responses to high-intensity exercise in a healthy population of endurance athletes with no self-reported perception of respiratory problems.

Methods: A cross-sectional study was conducted at Haukeland University Hospital, Bergen, Norway, inviting amateur and professional athletes with no self-reported breathing problems who performed endurance training minimum four sessions weekly. Thirty-six eligible athletes completed a questionnaire detailing exercise habits and past and current respiratory symptoms. They performed a standardised CLE test from which cardiopulmonary exercise data and corresponding laryngeal responses were recorded. The CLE tests were evaluated in retrospect by two independent raters according to preset criteria providing a CLE score. The CLE score rates the severity of laryngeal obstruction during moderate and maximum exercise on the glottic and supraglottic regions on a scale ranging from 0 (no obstruction) to 3 (maximum obstruction).

Results: Twenty-nine (81%) athletes (15 females) aged 15-35 years completed a CLE test. Ten participants (33%) had a supraglottic CLE subscore of 2 or 3. Among these, two also had a glottic CLE subscore of 2 or 3. Notably, none had isolated glottic obstruction.

Conclusion: In healthy well-trained endurance athletes with no prior perception of respiratory symptoms, the laryngeal response to high-intensity exercise was diverse. Supraglottic laryngeal obstruction was observed in one-third of the athletes. The findings underline that a diagnosis of EILO should rest on observed laryngeal obstruction supported by compatible symptoms.

Keywords: athlete; exercise; exercise testing; respiratory.

Figure 1

The continuous laryngoscopy exercise (CLE) scoring system. Scores were assigned at glottic (A and C) and supraglottic (B and D) levels, and at moderate (A and B) and maximal effort (C and D). The sum of these four scores constitutes the sum score (E) for each test/subject. For the purpose of this study, we regarded any score ≥2 as compatible with exercise-induced laryngeal obstruction. CLE grading system, reproduced with permission from Maat et al.

Figure 2

Recruitment of study participants with a continuous laryngoscopy exercise score ≥2 is compatible with exercise-induced laryngeal obstruction.