What Is Asthma?

Healthy breathing

Healthy breathing is effortless. A person who is breathing normally will not be aware of the process. Every minute of every day, the lungs expand and contract 15 times. This process allows the blood to deliver oxygen to red blood cells and to take away carbon dioxide.

Air enters the nose, where it is warmed and moistened. Then, it enters the trachea, a single tube that is the beginning point of the airways. The trachea divides into two narrower tubes called bronchi. Each bronchus is a way into the lungs. As the air travels through the lungs, it moves through progressively smaller tubes called bronchioles. At the tip of the last bronchiole it enters, the air comes into contact with hundreds of millions of tiny air sacs called alveoli. These sacs take in oxygen from the air in exchange for carbon dioxide. Eventually, the lungs will exhale the carbon dioxide.

For the exchange of oxygen for carbon dioxide to take place, the diaphragm, a sheet of muscle that separates the chest from the abdominal cavity, must contract. When the diaphragm contracts, a partial-vacuum effect occurs around the lungs, causing them to expand. When the lungs expand, air pressure in the chest cavity is lower than the air pressure outside. This difference in pressure causes air from the outside to fill the lungs. Each time this happens, approximately 1 pint of air enters the lungs.

When you exhale, the diaphragm relaxes. When the lungs deflate, carbon dioxide is forced out. While this entire process is taking place, mucus in the air passages is trapping any foreign materials that have entered your body with the air. After the mucus traps these particles, the mucus is carried by cilia (which look like tiny hairs) from the bottom of the lungs to the throat. Once the mucus reaches the throat, it is either swallowed or coughed out. If the mucus is not cleared, viruses, bacteria, and other impurities can collect in the lungs and cause infection or illness. Healthy lungs are grayish pink in color. Lungs that are damaged by pollutants can become blackened.

If your breathing is not healthy or normal, it might be due to allergies or even asthma. Allergies have been linked to asthma, so it is not unusual to find that a person suffers from both. These disorders can be treated, and sometimes the symptoms can even be prevented. With proper medical care and changes in behavior or environment, someone who suffers from allergies or asthma can breathe comfortably and live an active life.

Problems associated with asthma

Asthma is a chronic lung disease that makes breathing difficult. For an asthmatic, breathing becomes difficult for a variety of reasons. Airways can become inflamed, restricted, or blocked, so that very little air can travel to and from the lungs. The air that does get through these narrowed passages can cause a high-pitched or whistling sound called wheezing. The chest can also become tight or constricted, requiring the person to use more effort just to breathe. This is called labored breathing.

If a lot of viscous (thick) mucus is released in the airways, it can produce coughing. As the body tries to clear the mucus from the airways, a rattling sound often occurs. If the airways become plugged with mucus, the lungs can fully or partially collapse. This collapse can be caused by a number of conditions, from prolonged bed rest to pneumonia, and can be seen on a chest X ray. Unfortunately, when a collapsing lung is found — especially in combination with a rattling sound heard in the chest — asthma can be misdiagnosed as bronchitis or even pneumonia. Antibiotics are often prescribed for bronchitis and pneumonia, but these medications are not effective against asthma.

The symptoms of asthma

People with asthma experience symptoms that can include coughing, wheezing, congestion, and tightness in the chest. Most of these symptoms are usually associated with colds or infections. That is why it is important to notice when they reoccur for no apparent reason. When this happens, it could mean that you have asthma. Although asthma symptoms might resemble cold symptoms, they must be treated differently.

A viral infection, such as a cold, might make it hard to sleep at night for a few days. Nighttime asthma is very different. It can make getting proper rest nearly impossible for a long period of time. Some asthmatics have symptoms every night. People with nighttime asthma often have to sleep sitting upright in order to breathe. If these symptoms are disregarded as cold symptoms, then they will not be treated properly. A serious lack of rest can have dangerous consequences, especially for a developing child.

Symptoms of asthma are usually measured by their severity, frequency, and response to treatment. The National Institutes of Health has defined the following severity levels for asthma: mild intermittent, mild persistent, moderate persistent, and severe persistent. Those with the milder form of the disease might have brief episodes once a week. Asthmatics with the most severe form of the condition have symptoms that won’t go away, attacks that easily become crises, very little lung capacity, and restricted physical activity.

Whether symptoms appear to be mild or severe, it is crucial that they be evaluated. Even if you seem to experience symptoms only after exercise or during the night, an examination by a physician can be the first step in getting relief. For someone who has lived with the symptoms for a long time, the chest tightness and breathing difficulty can seem almost normal. Having problems with breathing, however, is never normal or healthy.

Even some less common symptoms of asthma require emergency help. If an asthmatic suddenly starts to sweat, seems lethargic (or dazed), appears fatigued, or has difficulty speaking, he or she should be taken to an emergency room. If the person has severe difficulty breathing, intense coughing, a racing pulse, or cyanosis (nail beds or lips that are bluish in color), these are also signs of an emergency.

Severity Levels for Asthma

Mild Intermittent

— About half of all asthma patients fall into this category, which is characterized by fewer than two or three asthmatic episodes per week and no difficulty sleeping at night. No continuous control treatment is necessary.

Mild Persistent

— Patients typically have tightness and wheezing weekly, but relatively normal lung function overall. One controlling medication is sufficient to manage the illness.

Moderate Persistent

— Daily episodes characterize this stage, but the flare-ups are manageable with two medications.

Severe Persistent

— Episodes occur daily, despite therapy with more than two controlling medications.

The causes of asthma

Scientists still do not know exactly what causes asthma. Researchers are investigating a number of possibilities, including smog, lack of exercise, obesity, too much exposure to indoor allergens, and even a lack of exposure to viruses and bacteria in childhood, which could weaken the immune system. It is likely that a number of factors combine to cause asthma.

Scientists do know that many people with asthma also have allergies, such as hay fever or eczema, or a family history of allergies. Others, however, have no history of allergies or evidence of allergic problems. Asthma also seems to run in families. If one parent has asthma, his or her children are more likely to have asthma. If both parents have asthma, there is a 40% chance that their children will develop the disease. Although several people in the same family may have asthma, the severity of their symptoms may not be the same. Even if identical twins have asthma, one twin might have a more severe case of it. Scientists do not know why this is so.

Although the exact causes of asthma may not be known, scientists do know a great deal about what happens inside the body when an asthma attack occurs. Specifically, three changes occur inside the airways in the lungs of people with asthma. The first change is inflammation (or swelling), which leads to constriction and sensitivity.

What Causes Occupational Asthma?

Direct exposure to irritants.

Substances such as hydrochloric acid, sulfur dioxide, and ammonia can trigger occupational asthma in those exposed to them. Commonly used in the petroleum and chemical industries, these irritants are particularly harmful to people with a history of respiratory disorders.

Allergic reactions from long-term exposure.

A worker’s immune system might take months or years before developing a reaction to a particular substance, but the symptoms can be quite severe. Everyday, common substances can trigger symptoms. A veterinarian can develop occupational asthma from exposure to animal proteins. A health care worker can suffer from asthma symptoms in reaction to the powder that lines latex gloves.

Accumulation in the body.

Over time, workers who inhale certain substances can experience asthma symptoms because of a buildup of naturally occurring chemicals in their bodies. For example, an insecticide that is used in farming can cause acetylcholine to build up in a farm worker’s body. This buildup can cause airway muscles to contract, resulting in an asthma attack.

Airway inflammation happens when the mucosa (or bronchial mucous membrane) swells. The inflamed tissues make a thick mucus, which is difficult to get rid of and can often produce coughing. This inflammation then leads to bronchoconstriction (or bronchospasm), in which the smooth muscle that surrounds the airways contracts too much, narrowing the airways and making it difficult to breathe. In people with asthma, inflammation also leads to sensitivity. This means that the airways are overly sensitive (or hyperresponsive) to even minor irritants. Such irritants can include tobacco smoke, air pollution, the common cold, or even cold air. If an asthmatic also has allergies, he or she can be overly sensitive to pollen, animal dander, or dust, for example.

Asthma can be triggered by both allergic and nonallergic reactions to various factors. Most asthma attacks are of the allergic variety, resulting from exposure to triggers such as animal dander and mold. These triggers exist in both indoor and outdoor environments. An asthma attack can result from high levels of pollen in the air or from cockroach droppings in household dust. A simple allergy skin test can help determine some of the triggers that cause the symptoms.

Nonallergic asthma can be triggered by exposure to viral infections, shifts in air temperature, physical exertion, chemicals, medications, or foods. Viral infections can bring on asthma especially in young children. When someone catches a cold, the nose, airways, throat, and lungs often feel irritated. This irritation can trigger asthma symptoms. A condition called sinusitis — in which the hollow cavities located behind the eyes and nose get inflamed — can cause asthma. Sinusitis can bring on wheezing, headaches, coughing, sinus pressure or pain, and postnasal drip. During an attack of sinusitis, excess mucus drains into the nose, throat, and bronchial tubes. This drainage can trigger or aggravate asthma.

Gastroesophageal reflux disease (GERD),

a condition in which stomach acid flows up through the esophagus, affects many people who suffer from asthma. The symptoms of GERD include severe heartburn, belching, frequent coughing, hoarseness, and asthma at night, as well as after meals and exercise. Some asthma symptoms are relieved by medications prescribed for GERD.

Another type of nonallergic asthma is called exercise-induced asthma. It is triggered by strenuous physical activity. Intense, prolonged breathing through the mouth can lead to coughing or tightness in the chest. Exercising in cold, dry air can also make breathing difficult.

Asthma symptoms that develop because of exposure to fumes, gases, dust, or other substances in the workplace are called occupational asthma. This type of asthma can develop in an asthmatic or in someone with no history of the condition. The symptoms of occupational asthma can continue even after the worker is no longer exposed to the substance that triggered the initial reaction. The symptoms can include a runny nose and eye irritation, as well as difficulty breathing. Occupational asthma symptoms often grow worse as the workweek progresses, get better over the weekend, and then resume when the person returns to work. Smoking can also worsen symptoms, as can being exposed to secondhand smoke.

A worker can be exposed to trigger substances for months or years before symptoms arise. Often, the symptoms of occupational asthma are misdiagnosed as bronchitis. This is dangerous because it can lead the worker to return to the environment that caused the symptoms. Continued exposure to triggers can be quite harmful. Employees are not the only people who can be affected by harmful substances in the workplace. Asthma can also occur in people who live near factories that release trigger substances into the environment. Leaving an asthma-inducing work environment within one to two years of the initial illness can reverse occupational asthma. For workers with the disease who smoke, research shows that those who leave the unhealthy work environment and quit smoking are more likely to recover fully than is a worker who changes jobs, but continues to smoke.

In developed countries, occupational asthma has become the most common form of work-related lung disease. According to the American Academy of Allergy, Asthma, and Immunology, up to 15% of asthma cases that have been diagnosed in the United States have some connection to job-related factors. In certain industries, the rate of occupational asthma is quite high. In some manufacturing companies, exposure to particular chemicals needed for producing plastics and foam has resulted in symptoms in 10% of exposed workers. Inhaling a single enzyme that is used to make washing powder has triggered asthma in 25% of exposed workers. In the printing industry, regular exposure to gum acacia, which is used in color printing, has produced asthma symptoms in 50% of the workers exposed to it.

An asthmatic can also experience an attack as a result of taking particular medications. Some of the most common medications that trigger asthma symptoms are aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen. In fact, according to the American Academy of Allergy, Asthma, and Immunology, up to 19% of adult asthmatics have sensitivities to aspirin or NSAIDs. Medications called beta-blockers — which are taken to address heart disease, high blood pressure, glaucoma, or migraines — can prompt asthma attacks as well.

In about 6-8% of children, certain foods and food additives can bring on asthma symptoms. Some of the most common products that trigger asthma attacks are milk, eggs, peanuts, tree nuts (for example, walnuts or almonds), soy, wheat, fish, and shellfish.

It is important to note that anxiety alone cannot give someone asthma. However, emotional factors can make asthma symptoms worse or attacks more frequent. For example, if a person is under stress, he or she will probably feel more fatigued. This fatigue can increase the number of asthma symptoms or make them more intense. An anxious person might be more likely to hyperventilate, which can worsen asthma symptoms.

How asthma affects the body

In general, if asthma symptoms are addressed early and managed consistently, there is little risk of significant damage. Each asthmatic episode does take a toll on the body, so it is best to try to prevent symptoms whenever possible.

When an asthma attack occurs, a person experiences more than just difficulty breathing. The inflammation and obstruction of the airways, both of which commonly occur during an asthma attack, can be associated with permanent changes in the body. The airways can become permanently narrowed. Usually, airway obstruction does not cause any serious damage to the lungs, heart, or other organs. However, severe asthma attacks can lead to permanent damage or even death. During such an episode, an asthmatic can lose consciousness or suffer brain damage because too little oxygen reaches the brain. This is one of the reasons that it is vital to seek medical help as soon as possible when a severe asthma attack occurs.

When people suffer from exercise-induced asthma, their symptoms often appear after only brief periods of activity. Their airways tend to be overly sensitive to sudden changes in temperature and humidity. When people exert themselves, they often breathe cold, dry air in through the mouth. This does not allow the natural warming and humidifying action of the nose to take place. People with exercise-induced asthma tend to develop a reduced capacity to add moisture and warmth to the air before it reaches the lungs.

In addition, they have more difficulty exercising in environments where air pollution and pollen are common.

How asthma affects lifestyle

Asthma affects daily life in many ways. Often, an asthmatic must restrict activities to avoid exposure to trigger substances and factors. An asthmatic must be cautious when taking a new medication, tasting a new food, or entering a new environment. A person with chronic asthma must remember to take daily preventative medications on time. When going out, many asthmatics must arm themselves with “rescue” medications for use in case of an attack.

Frequently changes must be made to an asthmatic’s home or work environment to make breathing easier. Sometimes, bedroom carpeting and drapes, which can be home to dust mites, should be removed. If the parents of an asthmatic child smoke, they should quit. If a factory worker develops occupational asthma from a substance in his or her work area, the person should change job locations or professions.

For many people, a common cold is just a brief annoyance. For an asthmatic, this minor infection can produce asthma symptoms.

Influenza (the flu) can bring on more severe symptoms for a person who suffers from asthma. It is very important for asthmatics to avoid exposure to these viruses whenever possible. It is wise for asthmatics to get yearly flu vaccines. If an asthmatic is exposed to a cold or the flu, rest and proper nutrition can help to prevent the symptoms from escalating to asthma.

Often, asthmatics have difficulty when they exert themselves in ways that require deep breathing. Sports such as soccer, basketball, and long-distance running, which demand continuous exertion, are more likely to trigger asthma symptoms. By contrast, sports like wrestling, gymnastics, baseball, and surfing require brief bursts of energy, which do not seem to aggravate asthma as often. Those who suffer from exercise-induced asthma are likely to find walking, slower-paced biking, hiking, and downhill skiing easier than the preceding sports. With treatment and careful training, an asthmatic can participate in almost any sport.