Shortness of breath, a symptom also known as dyspnea, describes a feeling of not getting enough air. Doctors at MayoClinic.com report that patients often describe shortness of breath as an intense tightening of the chest or a feeling of suffocation. Cough occurs as a reflex action when nerves in the respiratory tract become stimulated, and congestion describes blockage of the nasal passages or airways. Illnesses that affect the respiratory tract often cause all three symptoms together.
Common Cold
Anyone can fall victim to the common cold, with the average adult contracting two to three colds per year and the average child getting six to 10 colds per year, according to CommonCold.org. Rhinoviruses, which consist of over 100 viruses, cause approximately one-third of all common cold infections, according to The University of South Carolina School of Medicine.
Viruses causing colds become airborne in droplets released through sneezing and coughing. The virus usually enters through the nose, triggering an increase in mucus production that causes the common symptoms of nasal congestion, sneezing, sore throat and cough. The blocked nasal passages reduce the amount of air entering the lungs, resulting in shortness of breath.
Flu
The flu, a common viral infection, occurs due to infection by a strain of the influenza virus. The flu virus transmits from person to person through aerosolized droplets produced by coughs and sneezes. The influenza virus infects the epithelial cells in the respiratory tract, interfering with the ability to clear mucus. As mucus builds up, the viral particles multiply, causing symptoms such as fever, muscle aches, cough and nasal congestion.
Although symptoms caused by the flu usually remain mild, the Centers for Disease Control and Prevention reported that a strain of influenza virus caused 12,000 deaths in the United States in 2009. The accumulation of mucus in the airways causes shortness of breath and can lead to more serious conditions, including pneumonia.
Pneumonia
Pneumonia, or inflammation of the lungs, can occur due to a viral infection or a bacterial infection. An infection affecting the lungs often mimics the flu, beginning with a cough and fever, as described by MayoClinic.com. As the condition progresses, the increase in the amount of mucus in the airways causes additional symptoms, including congestion, shortness of breath, sweating, chills and chest pain.
Chronic Bronchitis
Bronchitis describes a condition characterized by inflammation and irritation of the bronchial tubes. Doctors diagnose the bronchitis as chronic when it lasts three months or more, according to the American Academy of Family Physicians.
When the bronchial tubes become irritated from inhaled substances such as tobacco smoke or chemical fumes, thick mucus lines the airways. The presence of this mucus causes congestion, triggers a chronic cough and inhibits the flow of air into the lungs, resulting in shortness of breath.
