Few sensations are as frightening as not being able to get enough air. Although shortness of breath -- known medically as dyspnea -- is likely to be experienced differently by different people, it's often described as an intense tightening in the chest or feeling of suffocation. Depending on the cause, you may experience shortness of breath just once or have recurring episodes that could become constant.

Very strenuous exercise, extreme temperatures, massive obesity and high altitude all can cause shortness of breath in a healthy person. Outside of these examples, shortness of breath is likely a sign of a medical problem. If you have unexplained shortness of breath, especially if it comes on suddenly and is severe, see your doctor as soon as possible.