Exercise Respiratory Center (ExRC)

EILO, (also called Vocal Cord Dysfunction, VCD, or paradoxical vocal fold motion, PVFM), occurs when the voice box narrows inappropriately during physical exertion, usually on inspiration only. This makes it difficult to breathe. There are different ways this can happen: 1) The vocal cords close partially or completely close (glottic EILO), 2) cartilage structures called arytenoids collapse (supraglottic EILO), or 3) both of these occur at the same time (mixed EILO). Symptoms may include rapid onset of breathlessness, noisy breathing, throat tightness, and difficulty breathing in. Typically, symptoms resolve within a few minutes of rest and common asthma inhalers do not provide relief. The gold standard for the diagnosis of EILO is a Continuous Laryngoscopy during Exercise (CLE). Once diagnosis is confirmed, most patients undergo speech therapy to learn both rescue and prevention breathing techniques that keep the vocal cords and upper airway open during intense physical exercise.

DB is an inefficient breathing pattern that causes shortness of breath or other symptoms, including dizziness, chest tightness, sighing, and frequent yawning. DB can manifest in a variety of different ways. Patients with DB might breathe fast and shallow or show a very chaotic pattern of breath sizes and breathing rate. They might rely on their accessory muscles too much (predominant chest and shoulder breathing) and not use their diaphragm efficiently. The way they use their diaphragm and accessory muscles to breathe might be out of sync. Patients might show some or all of these dysfunctional breathing patterns. DB is diagnosed based on symptoms, visualization of breathing patterns by a trained professional, and CPET analysis. Once diagnosed, specialized physical therapy treatments retrain the patient to utilize optimal breathing patterns that involve the diaphragm in every breath.

EIA and EIB combined are the most common causes of exercise-induced respiratory symptoms. EIA is the triggering or worsening of existing asthma by exercise. EIB is common in patients with asthma, but can also occur in otherwise healthy people, including children and adolescents. Both occur when the small airways in the chest narrow during and after exercise, leading to symptoms that may include wheezing, difficulty breathing, chest tightness, and cough. These symptoms are typically worse after exercise is over rather than during exercise. Diagnosis of EIA and EIB includes performing lung function testing before and after exercise or before and after certain stimuli or medication. Once the diagnosis is confirmed, EIA/EIB can be successfully treated or prevented with asthma medication. When exercise-induced respiratory symptoms do not respond to asthma medication, other diagnoses like EILO and DB should be considered. Learn more.

CLE is the gold standard for diagnosing EILO. A small flexible camera is inserted through the nose to the back of the throat so that the voice box can be seen. Once the camera is secured in place, the patient runs on a treadmill in order to elicit their symptoms so that we can watch how the voice box behaves in real time. We combine the CLE with a cardiopulmonary exercise test (CPET; see What is CPET) during which patients run at increasing speed for approximately 8-12 minutes until they fatigue. We share the video of the voice box with the patient and their family and discuss whether EILO is the cause of their symptoms.

CPET is the gold standard for assessing the health, function, and fitness of an individual’s heart, blood circulation, and lungs (cardiorespiratory fitness and function). To perform a CPET, a patient runs on a treadmill or rides a stationary bicycle while breathing through a mask. This allows us to analyze the amount of air patients breathe, the amount of oxygen they use, and the amount of carbon dioxide they produce when their body creates the energy used to exercise. Additionally, we monitor patients’ blood pressure, oxygen saturation, and heart rhythm. The patients start running at a slow speed. The treadmill speed then increases every 2-3 minutes until the patient has reached their maximal capacity; the entire test usually lasts 8-12 minutes. The information gathered during the test allows us to diagnose cardiovascular and pulmonary causes of exercise-induced symptoms and to measure patients’ cardiorespiratory fitness.