Dyspnea is defined as an uncomfortable awareness
of breathing.10 It is a subjective sensation for which
there is no accurate objective measurement. Dyspnea
is usually the result of a cardiac or pulmonary disease
process, although healthy individuals may experience
dyspnea with exercise. The most common pathological
causes of dyspnea include asthma, congestive heart
failure, chronic obstructive pulmonary disease, pneumonia,
and cardiac ischemia.11 The mechanisms of
dyspnea are not well understood.