Breathing is a largely involuntary process that is necessary for survival. We have very limited control over the normal breathing processes that respond automatically to the variation in the needs of the body. We inhale and exhale air without a second thought since no pain or discomfort accompanies the breathing process. Under normal circumstances we inhale and exhale about 12 to 20 times every minute but this rate varies according to the level of physical activity and age.
Understanding the Breathing Process
Breathing is a complex process. The whole cycle of breathing can be subdivided into two phases: inhalation phase and exhalation phase. During the inhalation phase, air from the environment enters the body through the nose or mouth, and travels down into the lungs through the passages provided by the pharynx, larynx, trachea, and bronchi.
Within the lungs, the exchange of gases takes place. The oxygen from the inspired air is picked up by the blood, while the carbon dioxide present in the blood is released into the airways. The exhalation phase moves the carbon dioxide-rich air out through the same passages that the inhaled air traversed while coming in.
The movement of air during the inhalation and exhalation phases is driven by the coordinated action of many respiratory muscles. The diaphragm is the main respiratory muscle. It is a large dome-shaped muscle that sits just below the lungs and separates the thoracic cavity from the abdominal cavity. The diaphragm is assisted by the intercostal muscles present between the ribs.
Contraction of the dome-shaped diaphragm flattens it, leading to the creation of negative pressure within the chest cavity. This negative pressure in the chest causes the lungs (and the chest wall) to expand. This expansion of the lungs and the chest cavity drives the inhalation process.
The exhalation process is triggered when the diaphragm relaxes and creates a positive pressure within the chest cavity. This positive pressure makes the lungs recoil back to their original position, thereby pushing the air out. Accessory respiratory muscles of the chest wall and the neck also help in the process of inspiration and expiration.
Pain When Breathing
Normally, the act of breathing happens without any pain or discomfort. In fact, we are hardly aware of our breathing process until the our physical exertion increases or something goes wrong with the breathing process. Upon increased physical exertion (such as during sports activities), breathing may become strenuous, uncomfortable, and even painful.
However, this situation quickly resolves as the body comes to rest and we catch up on our breath. No treatment is required in such normal physiological conditions. However, in some cases, breathing may become painful, and remain so without medical attention. Pain during breathing may occur even during a resting state. Such cases should be investigated as they may indicate the presence of an underlying medical problem that will not resolve without treatment.
Read more on chest pain during breathing.
Causes of Painful Breathing
Pain during breathing is mostly felt in the chest region. However, pain in other parts of the body may also be exacerbated by breathing. The most common sites of pain during breathing are the airways, lungs, and other organs within the chest cavity. Since breathing also causes pressure changes within the abdominal cavity, pain during breathing can also arise from the abdominal organs.
One of the most common causes of painful breathing is trauma to the chest wall and the organs contained within. Injuries to the airways, lungs, chest muscles, bones and cartilages of the rib cage, can all cause pain during breathing. Trauma may include a blunt blow to the chest, a piercing injury caused by a sharp object, fracture of the bones, inhalation of toxic gases and smoke, and injury caused by surgical procedures.
At times, even wearing very tight clothing on the chest can cause chest wall injury. Pneumothorax can also cause painful breathing, and is characterized by accumulation of air around the lungs. Mechanical ventilation, lung diseases, surgical procedures, and injuries to the outer chest wall can cause the entry of air into the space around the lungs. Most of these trauma can be easily identified as the reason for painful breathing.
In some cases, painful breathing may occur weeks after a traumatic event like surgery.
Lung infections are very common causes of painful breathing. Examples include pneumonia, tuberculosis, bronchitis, pleuritis, psittacosis, and other lung diseases caused by a variety of viruses, bacteria, and fungi. Infections in other parts of the respiratory system can also cause pain during breathing. Examples include sore throat (technically referred to as pharyngitis), infection of the voice box (technically referred to as laryngitis), and infection of the trachea (technically referred to as tracheitis).
Painful breathing can also occur upon infection of the linings around the lungs and the heart. The lining around the lungs is known as the pleura, and the inflammation of the pleura is referred to as pleuritis. The lining around the heart is known as the pericardium, and the inflammation of the pericardium is referred to as pericarditis. Pleuritis and pericarditis cause pain especially during deep inhalation. Sometimes, conditions that affect the outer chest wall (such as shingles) can also cause pain during breathing.
Read more on breathing problems.
The fracture of the bones of the rib cage is a common cause of pain during breathing. Pain caused by fracture is usually felt at all times. However, it is exacerbated by the movements of the chest wall during breathing. Fractures of the ribs, sternum (also known as the breastbone), and the scapula (also known as the shoulder bone) are most frequently associated with painful breathing.
Pain during breathing can also occur due to fractures of the clavicle (also known as the collar bone), vertebrae, and the pelvic bone. Besides fractures, conditions such as costochondritis and Tietze’s syndrome are also capable of causing painful breathing. These conditions cause inflammation of the joints and the cartilages that join the sternum and the ribs, and can be mistaken for rib or sternal fractures.
Some other less common causes of painful breathing include aspiration pneumonia, decompression sickness, lung abscess, subphrenic abscess, lung cancer, pulmonary embolism, esophageal tears, hiatal hernia, Dressler syndrome, bronchogenic carcinoma, tracheobronchial tear, mesothelioma, and necrotizing granulomatous angiitis.