Effect of Heliox on laryngeal closure during exercise (HELI-CLE)
Research type
Research Study
Full title
Effect of Heliox on laryngeal closure during exercise
IRAS ID
359694
Contact name
James Hull
Contact email
Sponsor organisation
Guy's and St Thomas' NHS Foundation Trust
Duration of Study in the UK
3 years, 0 months, 1 days
Research summary
This study is looking at a condition called Exercise-Induced Laryngeal Obstruction (EILO), which causes breathing problems during exercise, especially in active young people. EILO happens when the larynx (voice box) narrows/ closes during hard exercise.
The primary aim of the study is to see if breathing a special gas mixture called Heliox (a mix of helium and oxygen) can help reduce laryngeal closure in people who have EILO. A secondary aim is to assess whether Heliox can make people feel less breathless during exercise.
The study will involve at least 15 adults who have been diagnosed with EILO. During an initial visit, the participant will complete a maximal exercise test on a cycle ergometer. On the next visit, each person will undergo two exercise bouts, in a random order. One bout the participant will exercise whilst breathing Heliox, and on the other, they will exercise whilst breathing normal room air. This is a double-blind study, where the neither the participants, nor the assessors know which gas is being used.
During the exercise tests, a tiny camera will be used to look at the larynx, and participants will be asked about their breathlessness. The study hopes to understand if changing the airflow with Heliox can improve EILO symptoms, which could lead to a better understanding of why the condition occurs.
REC name
Yorkshire & The Humber - Sheffield Research Ethics Committee
REC reference
25/YH/0220
Date of REC Opinion
20 Nov 2025
REC opinion
Further Information Favourable Opinion