Dyspnea
The healthy adult at rest involuntarily inhales and exhales some 20,000 times a day, as naturally as seawater slides back and forth in a tidal zone. This cycle is so routine and rhythmic that we hardly notice it – except when something goes wrong, such as when we can’t seem to get enough air into our lungs. A number of easily identified disorders can cause such shortness of breath (dyspnea, in technical terms), including asthma, lung infections and chronic obstructive pulmonary disease. Congestive heart failure, in which the heart no longer pumps normally and so cannot deliver enough oxygen and nutrients to the body, is also well known to disrupt breathing. But absent any of those conditions, patients who are out of breath are also out of luck in terms of getting an accurate diagnosis – or an effective treatment.