Exercise-induced laryngeal obstruction
Exercise-induced laryngeal obstruction (EILO) is a temporary narrowing of the voice box that happens during intense exercise. It can block air flow and cause shortness of breath, a noisy breathing sound (stridor), and throat or upper chest discomfort.
Who gets it: EILO is common in teens and young athletes and is often mistaken for asthma or exercise-induced bronchoconstriction (EIB). It may happen when the structures of the larynx don’t stay open during hard breathing.
Why it happens: When you breathe fast and hard, air moves quickly and creates negative pressure across the larynx. This can pull the laryngeal parts together and narrow the opening. Sometimes the vocal cords themselves close during exercise. Both mechanical issues and neuromuscular control problems can be involved.
Where it occurs: The narrowing usually involves the supraglottic area above the vocal cords; in some people the vocal cords (glottic area) close too.
When it starts: EILO occurs during hard exercise and tends to get worse as intensity increases. The closure makes breathing work harder and tires the breathing muscles.
How common: In adolescents in northern Europe, about 5–7% are affected. It may be more common in highly trained athletes and appears to affect more females in some studies. One study found an average age around 15, with most participants being female.
Coexistence: EILO can cause cough and wheeze and can occur with asthma or EIB. In some groups of athletes with unexplained symptoms, about a third have EILO, and some have both EILO and EIB.
Diagnosis: The gold standard is continuous laryngoscopy during exercise (CLE). A flexible camera is placed through the nose and held in place while the person exercises on a treadmill, cycle, rower, or swims, allowing doctors to see changes in the larynx. A four-point grading system looks at the glottic and supraglottic areas; grades 2–3 indicate EILO.
Treatment: The main approach is therapy-based breathing techniques to reduce turbulent airflow and prevent closure (often called biphasic breathing or EILOBI). Biofeedback during exercise can help. The role of inspiratory muscle training is not yet clear. In some cases, surgery to widen the upper larynx (supraglottoplasty) has helped. It’s important not to rely on asthma inhalers if they aren’t needed.
This page was last edited on 3 February 2026, at 08:24 (CET).