Shortness of breath, or dyspnea, may cause you to feel that you can't get enough air in your lungs, or that you are suffocating. You may also experience a tightening sensation in your chest. If you have shortness of breath while exercising, it could be from exercise that is more strenuous than you are accustomed to; extreme temperatures, poor physical condition and high elevations can also play a role. As unexplained shortness of breath may indicate a serious underlying medical condition, consult with your doctor as soon as possible if your shortness of breath is new or is getting worse.
Shortness of breath while exercising is sometimes a sign of asthma, which involves a narrowing and swelling of airways. Along with having difficulty catching your breath while exercising, you may cough. Often there will often be a whistling or wheezing sound on exhaling. Exercise-induced asthma can increase when the air is cold and dry. See your doctor if you have signs of asthma.
Bronchitis or Penumonia
Both the respiratory illnesses bronchitis and pneumonia can cause shortness of breath with exercising. Acute bronchitis, an inflammation of the bronchial tubes, can occur from a cold or respiratory infection; chronic bronchitis -- a constant inflammation -- can result from smoking. With bronchitis you will also cough up mucus, have fatigue, fever and chills, and chest discomfort. Pneumonia, a lung infection caused by bacteria, viruses, fungi or parasites, can be mild or severe. In addition to shortness of breath, you will usually have fever, cough, sweating, chills and pleurisy -- or chest pain -- that changes with your breathing. See your doctor if you have a persistent cough or fever that lasts more than three days.
Congestive Heart Failure or Heart Attack
With congestive heart failure, the heart can't pump enough blood to the body's organs. The American Heart Association says this condition can be caused by scar tissue from a past heart attack, high blood pressure, heart disease and endocarditis, an infection in the lining of the heart. Symptoms include shortness of breath on exertion or exercise, along with fatigue and edema -- or swelling -- of feet, ankles and legs. If your shortness of breath worsens when you are lying down, this is an indication that you could be having congestive heart failure. If you have these symptoms, see your doctor immediately. With a heart attack, part of the heart muscle is damaged or dies due to lack of oxygen. If shortness of breath lasts more than a few seconds, or is accompanied by pressure or pain in your chest, sweating, dizziness, nausea or overwhelming fatigue, seek emergency medical care.
A pulmonary embolism is a sudden blockage in a lung artery, usually due to a blood clot. With a pulmonary embolism, you will not only have unexplained shortness of breath, but may also have chest pain and coughing. FamilyDoctor.org notes that blood in coughed-up mucus is another indication of pulmonary embolism. The National Heart Lung and Blood Institute says that pulmonary embolisms can be life-threatening; if you believe you have one, seek emergency medical care.