Breathing occurs when the diaphragm muscle contracts to allow the lungs to expand, which pulls air into the mouth and nose. The air travels through the trachea that branches into the two bronchi leading to the lungs. Once in the lungs, the air travels through the bronchial tubes and smaller bronchioles that lead to the alveoli—tiny air sacs surrounded by capillaries where the exchange of oxygen and carbon dioxide occurs. Conditions and diseases that cause breathing problems interfere with these processes.
Allergies
Allergies cause the immune system to overreact to normally harmless substances. Inhaled allergens, such as pollen, dust and pet dander, cause the immune system to produce antibodies and release inflammatory chemicals, resulting in swelling of the nasal passages and airways, and an increase in the production of mucus.
The symptoms of seasonal allergies, also called hay fever, include sneezing, congestion and itchy, watery eyes. As the bronchial tubes become inflamed and an excess of mucus builds up, the flow of air into the lungs becomes restricted. Allergies are some of the most common causes of breathing problems, affecting 1 in 5 Americans, making it the sixth leading cause of chronic illness, according to the Cleveland Clinic.
Asthma
Asthma describes a chronic lung disease that affects 22 million people in the United States, according to the National Heart Lung and Blood Institute. Asthma causes the airways to become inflamed and sensitive to outside irritants, such as inhaled allergens, chemical fumes or cold air.
The outside irritants, which differ for each person, cause the smooth muscles surrounding the airways to contract, resulting in airway constriction. In addition, asthma causes an increase in mucus production. These reactions all cause the airways to narrow, restricting the flow of air into the lungs. Although the symptoms, including wheezing, shortness of breath and cough, can be controlled with medication, asthma can cause serious breathing problems that can lead to respiratory distress, or a lack of oxygen in the blood.
Emphysema
Emphysema, a chronic lung disease, most commonly occurs due to smoking. Emphysema causes the destruction of the air sacs, or alveoli, which reduces the amount of oxygen entering the bloodstream. Emphysema causes shortness of breath, chronic cough, wheezing, chest tightness, loss of appetite and fatigue.
Emphysema is one of the major contributing factors of chronic obstructive pulmonary disease, according to MayoClinic.com. Chronic obstructive pulmonary disease, also known as COPD, gets progressively worse over time.
