Exercise induced inspiratory symptoms (EIIS) is increasingly recognized as an important differential diagnosis to exercise induced asthma (EIA) in otherwise healthy adolescents. EIIS is most often linked to laryngeal abnormalities and if so, often labelled exercise induced laryngeal obstruction (E-ILO). In unselected populations, E-ILO has been found in 7.5% and 5.7% of adolescents. Causal mechanisms remain unclear, and a variety of structural and/or functional pathways have been proposed, such as abnormalities related to the epiglottis, the laryngeal cartilage-skeleton or its support, mucosal structures as well as the laryngeal muscular system or its nerve supply. All these abnormalities might conceivably disturb the airflow on its way through the laryngeal inlet, increase the turbulence and the airflow resistance, and thereby set up a sense of dyspnea and trigger the symptoms that are characteristic of EIIS. Additionally, various psychological characteristics have been proposed to be implicated in this causal cascade.