Breathing problems include any symptom or condition that affects the function of the respiratory system. They can take many forms, including:

• Shortness of breath. A feeling of not getting enough air, which may leave a person gasping. It is also known as dyspnea.
  
  
• Wheezing. A whistling or high-pitched sound that results when breathing tubes are narrowed (or constricted) or obstructed.
  
  
• Apnea. Spontaneous breathing that stops for any reason. It may be temporary (starting and stopping at intervals) or prolonged.
  
  
• Respiratory arrest. A life-threatening disorder that requires emergency medical attention. It is the result of excessive loss of oxygen or excessive increase of carbon dioxide in the blood.
  
  
• Hyperventilation. Respiration faster than the body requires. It results in an excessive loss of carbon dioxide from the body.
  
  
• Coughing. A forceful movement of air that clears material from the airway, but often causes discomfort. It sometimes is accompanied by shortness of breath, chest pain and other symptoms.
  
  
• Stridor. A crowing sound audible during inhalation that is the result of blockage in the throat (pharynx), voice box (larynx) or windpipe (trachea). It often is loud enough to be heard from a distance and can indicate a life-threatening emergency.
  
  
• Cyanosis. A bluish discoloration of the skin that results when blood in the body lacks the proper oxygen content and turns bluish as a result. Many conditions that affect the lungs, blood vessels and heart can cause cyanosis.
  
  
• Cardiac asthma. A cluster of breathing problems (e.g., shortness of breath, coughing, wheezing) that is one of the first signs of heart failure. It begins when the left ventricle of the heart is unable to handle the blood flow being pumped by the right ventricle. It is not actually asthma, but mimics the symptoms of that condition.