Exercise intolerance is a general term for the inability to complete a reasonable exercise task. Exercise capacity varies from person to person, so this is best judged with respect to a person’s prior capacity or with respect to relative large groups of peers. It can be caused by deconditioning (a loss of fitness/endurance) or by deficits in nearly any organ system. In pediatrics, subtle breathing problems are a very common cause of exercise intolerance, especially considering that over 10% of Denver’s population has asthma. Previously unrecognized heart problems are, in relative terms, much less common than asthma.
The symptoms of exercise intolerance include shortness of breath out of proportion to what is expected for a given task. Fainting during exercise, especially in families with genetic heart problems, is a concerning symptom. Muscle weakness and tingling are fairly common symptoms as well.
The diagnostic evaluation of exercise intolerance varies somewhat from person to person. The most important step is a thorough interview and physical examination, which is often all that is needed. Observation of the symptoms in an exercise lab can be very helpful both for patients and the medical team. Medical teams often evaluate resting lung function and heart rhythm as well.
The treatment of exercise intolerance depends on the cause. Clearly the treatment of asthma will be different than the treatment of problems in other organ systems. Our ability to work with a variety of specialists speeds the time to improvement if problems unrelated to breathing are detected.