Dyspnea is commonly referred to as troubled or labored breathing while an excessively rapid breathing is called tachypnea or polypnea. The respiratory system consists of the nose, throat (pharynx and larynx), windpipe, and the lungs. Inspiration is the process of inhaling air through the nose which is then carried down to the lungs. The oxygen from this air is transferred to the red blood cells in the lungs and the carbon dioxide is transferred from the red blood cells into the lungs. This is then taken out of the body through the nose. This is called expiration. Together the process of inspiration and expiration is called breathing and this process is controlled by the respiratory center in the brain and nerves in the chest. Diseases that affect the respiratory system or the respiratory center in the brain can bring about breathing difficulties such as dyspnea or tachypnea.
Dyspnea or tachypnea can also be associated with other symptoms like the belly and chest moving during the process of breathing, nostrils flaring, breathing with an open mouth, breathing with the elbows sticking out from the body, neck and head held low and out in front of the body, noisy breathing called stridor or fast breathing and shallow breaths. Other symptoms like cough could be present depending on the cause of the breathing problem.
