Chronic obstructive pulmonary disease (COPD) is a progressive and eventually debilitating lung disease, which means the condition gets worse over time. The disease usually causes coughing, wheezing, and shortness of breath, making it difficult to breathe.

According to the National Institutes of Health, COPD is the third leading cause of death in the United States. The American Lung Association reports that more than 11 million people in the United States have been diagnosed with COPD. However, about 24 million more people may have the disease and not know it. Globally, COPD affects approximately 65 million people.

COPD most commonly occurs in people who are over age 40 and who have a history of smoking. Various factors may contribute to the development of COPD, including prolonged exposure to air pollutants and dust. However, cigarette smoking is far and away the leading cause of the disease. In fact, smoking causes about 90 percent of COPD cases.

What Is COPD?

Knowing how the lungs work can help you understand how COPD affects the lungs.

When you breathe in, oxygen-rich air goes down your windpipe and into small tubes located in your lungs. These tubes are called bronchial tubes or airways. They branch off into numerous tinier and thinner tubes known as bronchioles. At the end of the bronchioles are small, round air sacs called alveoli, which have tiny blood vessels called capillaries. When air enters the alveoli, oxygen moves through the capillaries and into the bloodstream. At the same time, carbon dioxide, which is a gas your body doesn’t need, moves into the alveoli so you can breathe it out.

Your lungs, airways, and air sacs are normally elastic. When you breathe in, they fill up with air, similar to a balloon. When you breathe out, they deflate and the air leaves the body. In people with COPD, however, less air flows into and out of the airways for one or more of the following reasons:

  • The lungs, airways, and air sacs lose their elasticity.
  • The walls between the air sacs are destroyed.
  • The walls of the airways thicken and become swollen.
  • The airways make more mucus than normal, which can clog airways.

These problems are usually caused by emphysema or chronic bronchitis. Both of these conditions are referred to as COPD.

Emphysema occurs when cigarette smoke or other air pollutants, such as dust or fumes, damage the walls between your air sacs over time. As the air sacs weaken, their walls break open, creating one large air sac instead of many smaller ones. This makes it more difficult for the capillaries to absorb enough oxygen and for the body to expel carbon dioxide, making it progressively harder to breathe.

Chronic bronchitis occurs when the airways become inflamed and produce a lot of mucus. The extra mucus causes a cough and makes it more difficult to breathe. Like emphysema, chronic bronchitis can develop when you smoke frequently or regularly breathe in air pollutants.

The symptoms of COPD include:

  • a persistent cough that produces a lot of mucus
  • shortness of breath, especially during exercise
  • a wheezing sound while breathing
  • a barrel-chest deformity
  • tightness in the chest

COPD can lead to serious complications. You should go to the emergency room right away if you have any of the following symptoms:

  • difficulty talking or breathing
  • blue or gray fingernails or lips
  • a lack of mental alertness
  • a very rapid heartbeat
  • severe COPD symptoms that get worse despite treatment

How Does Smoking Contribute to COPD?

According to the World Health Organization, smoking is the primary cause of COPD. This includes smoke from cigarettes, cigars, and pipes as well as secondhand tobacco smoke exposure. People are exposed to secondhand smoke when they breathe near someone who’s smoking.

Tobacco smoke and secondhand smoke travel, like the air you breathe, down through the windpipe and eventually into the bronchial tubes. The toxic smoke then moves into the bronchioles, which contain the minuscule clusters of air sacs known as alveoli. Within the alveoli are the capillaries. When you inhale, the oxygen moves through the alveoli and into the capillaries, allowing oxygen to be distributed to the rest of the body. Simultaneously, carbon dioxide is transported from the capillaries into the alveoli so it can be removed from the body when you exhale. This process is known as a gas exchange.

The elasticity of the air sacs enables this exchange to occur smoothly. However, people who regularly smoke or who are frequently exposed to secondhand smoke eventually develop lung damage. This allows less air to flow in and out of the airways due to the:

  • stiffening of the air sacs
  • deterioration of the walls between air sacs
  • thickening and inflammation of the airway walls
  • increased production of mucus in the airways, causing air obstruction

Cigarette smoke contains harmful toxins that affect lung functionality. Toxins that are inhaled directly into the lungs over prolonged periods of time can lead to severe lung irritation, triggering the onset of COPD. As long-term exposure to tobacco smoke continues, the lungs become even more damaged. This leads to inflammation and degradation.

Can You Reverse Lung Damage Caused by Smoking?

There’s no cure for COPD and lung damage can’t be reversed. However, some medical treatments and lifestyle adjustments can help you feel better, improve your overall health, and prevent your symptoms from getting worse.

Some medical treatments that can help relieve COPD symptoms include:

  • bronchodilators, which relax the muscles around the airways to make breathing easier
  • inhaled glucocorticoids, or steroids, which can help reduce inflammation of the airways, especially when used along with bronchodilators
  • flu and pneumococcal vaccines to reduce the risk of getting the flu and pneumonia, which are particularly problematic for people with COPD
  • pulmonary rehabilitation, which is a program of exercises overseen by healthcare professionals to help with the management of symptoms
  • oxygen therapy, which delivers oxygen into the body through nasal prongs or a mask to make it easier to breathe
  • a bullectomy, which is a surgery that involves removing destroyed air sacs to make it easier to breathe
  • a lung volume reduction, which is a surgery that involves removing damaged tissue from the lungs to improve lung function
  • a lung transplant, which is a surgery that involves replacing a damaged lung with a healthy lung from a donor and is generally done as a last resort

Some lifestyle changes that may ease symptoms include:

  • quitting smoking if you smoke
  • avoiding secondhand smoke and places with air pollution
  • having a diet that largely consists of vegetables, lean proteins, and whole grains
  • exercising at least three times per week

When they’re used in combination, these medical and lifestyle remedies can slow down the progression of COPD and decrease the severity of symptoms. The best way to prevent the disease from getting worse is to quit smoking immediately and to avoid secondhand smoke. People who continue to smoke put themselves at an increased risk of accelerating the disease and its symptoms.