Dyspnea is the medical term utilized to describe the subjective sensation of difficulty in breathing (shortness of breath or “air-hunger”). A patient typically complains that ther air is not adequate or that a deep breath is needed to satisfy his/her needs. Dyspnea, as a subjective entity, may be present even if objectively measured oxygen saturation and respiratory rate (number of breathes per minute) are within normal levels.
Dyspnea immediately after prologned and intense physical exercise is expected in practically everyone, however it should recede shortly after rest. In contrast, it is considered abnormal if dyspnea presents at rest, low intensity physical exercise or during asleep periods with a result to wake up the person in question. The origin of dyspnea may lie in the lungs, the heart, anemia, or even conditions related to psychological stress. As far as cardiac causes are concerned, dyspnea may be attributed to a variety of abnormal conditions either acute (e.g. pulmonary embolism) or chronic (e.g. heart failur, valvulopathies, arrhythmias).