A continuous laryngoscopy during exercise (CLE) test looks at your larynx (voice box) during exercise. It uses a laryngoscope, which is a thin, flexible tube with a camera lens at the end.  

Why is a CLE test needed?

Some patients have trouble breathing whilst they exercise. This is because their voice box narrows as they exercise. Exercise-induced laryngeal obstruction (EILO) is often misdiagnosed as asthma.

EILO is difficult to diagnose during a consultation or normal breathing test where you blow into a tube. With a CLE test we can see if you voice box is causing any of the breathing problems you are experiencing.

We can then recommend treatment such as specialist physiotherapy to help your condition.

How is the CLE test carried out?

We will first ask you to blow into a tube so we can check how well your lungs are working. This is a normal breathing test, also called a spirometry test.

We then use a local anaesthetic gel or spray to numb one of your nostrils. We will then pass the laryngoscope up the nostril to the back of your throat. Some patients may experience a little discomfort in this area, but it does not hurt.

You will wear some light headgear to hold the tube in place as you exercise. This is so you can exercise with ease and not worry about the tube.

Your exercise will be on an exercise bike or treadmill. You can stop the exercise at any time. We will also track your blood oxygen levels your heart rate during the test.

A doctor and physiology staff will be present during the test and can answer any questions you may have.

The Trust’s paediatric difficult asthma service has an international reputation for the assessment and management of children with difficult to control asthma. 

Dr James Hull introduced the CLE test at the Trust.

Useful documents

Read our patient leaflet on continuous laryngoscopy during exercise.
Your continuous laryngoscopy during exercise test - April 2024 (PDF, 101KB)