Unexplained Dyspnea & Exercise Intolerance

About Unexplained Dyspnea and Exercise Intolerance

Shortness-of-breath, or Dyspnea, is a common symptom that causes exercise limitation or “intolerance”. Breathlessness during exercise is often the first sign that “something is not as it used to be”. This can prompt referrals to cardiologists and pulmonologists for further evaluation. However, the potential causes of unexplained dyspnea are very broad, which it is why it is not uncommon for patients to undergo several different clinical tests before a diagnosis can be found.

A systematic approach is used to determine the underlying causes of breathlessness. There are many diseases that may produce dyspnea, however about 2/3rds of cases result from a pulmonary or cardiac condition. Causes may also be due to problems with the nerves or muscles that control breathing, including psychogenic causes.

Assessment of unexplained dyspnea starts with a comprehensive history, physical examination, and basic blood tests, and continues on to heart and lung tests. Cardiopulmonary exercise testing – invented by investigators in our research team – is used to recreate the conditions that brought about the sensations of breathlessness in the first place i.e., exercise. The measurements of made during the cardiopulmonary exercise test are important to uncover the reasons of unexplained dyspnea when initial test results are inconclusive. The cardiopulmonary exercise test provide accurate diagnostic data to allow physicians to choosing an appropriate treatment.

Our Research

Our investigators research the contribution of dyspnea to limiting exercise capacity. We conduct randomized clinical trials to test drugs and devices designed to reduced dyspnea and increase exercise endurance in a wide range of chronic diseases including COPD, asthma, heart failure and pulmonary hypertension.  Help advance medicine and medical research through participating in one of our clinical trials.

Other Resources

Learn more about Dyspnea and exercise intolerance and the current research

Respiratory Research Center

Our Research Contributions

  • Evaluated new bronchodilator and anti-inflammatory drugs intended to improve lung function and exercise tolerance in COPD patients
  • Developed new cardiopulmonary exercise testing methods to quantify the contribution of muscle fatigue and dyspnea to exercise limitation
  • Developed the framework for using exercise endurance as a patient-focused meaningful outcome in COPD clinical trials

More of Our Research Specialties

  • Asthma

    Asthma is a condition in which your airways narrow and swell and may produce extra mucus. This can make breathing difficult and trigger coughing, a whistling sound (wheezing)

  • Exercise Training and Rehabilitation

    Pulmonary rehabilitation (PR) is a supervised medical program that helps people who have lung diseases live and breathe better.

  • Muscle Weakness

    There are many reasons why individuals may lose strength, but in many patients with chronic heart, lung or kidney diseases the loss of muscle mass and strength is faster than normal.

  • Pulmonary Hypertension

    Pulmonary Hypertension (PH)  is a disease of high blood pressure in your pulmonary artery. This is the large artery that leaves the heart and goes to your lungs.