Shortness of breath is normal with strenuous activity, excitement, or clogged nasal passages and is not a cause for concern. However, unexplained shortness of breath can be a sign of a significant lack of oxygen and may be cause for serious concern. Forms of breathing difficulty are wheezing and hyperventilation, both of which may be attributable to respiratory disease and other lung disorders. Breathing difficulties may also accompany a wide variety of other conditions: mental depression or anxiety, tingling sensation in the fingers, obesity, rapid ascent to high altitudes, airway obstruction, cigarette smoking, inhalation of a foreign object, dust-laden environment, medications (such as amphetamines), asthma, emphysema, allergies (such as mould, dander, pollen), anaphylaxis (extreme allergic reaction), congestive heart failure (CHF) and pulmonary alveolar proteinosis.
In Chinese medicine, wheezing most often suggests mucous. Shortness of breath or weak respiration, accompanied by weak, low voice suggests deficiency.