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Chronic Obstructive Pulmonary Disease (COPD)

Medically reviewed by Last updated on Feb 15, 2023.

What is Chronic Obstructive Pulmonary Disease (COPD)?

Harvard Health Publishing

Chronic obstructive pulmonary disease (COPD) refers to a group of disorders that damage the lungs. These disorders make breathing increasingly difficult over time.

The most common forms of COPD are chronic bronchitis and emphysema. Both are chronic illnesses that impair airflow in the lungs. Most cases of COPD are related to cigarette smoking.

Chronic Obstructive Pulmonary Disease (COPD)

Chronic Bronchitis
In this disorder, the air passages in the lungs are inflamed. And the mucus-producing glands in the lung’s larger air passages (bronchi) are enlarged. These enlarged glands produce too much mucus. This triggers a cough. In chronic bronchitis, this cough is present for at least three months out of the year for two or more consecutive years.

You are more likely to develop chronic bronchitis if you:

  • Smoke tobacco
  • Are exposed to air pollution
  • Are exposed to airborne organic dusts or toxic gases in the workplace. Cotton mills and plastic manufacturing plants carry particularly high risk.
  • Have a history of frequent respiratory illnesses
  • Live with a smoker
  • Have an identical twin with chronic bronchitis

In this disorder, the tiny air sacs in the lungs (alveoli) are destroyed. The lungs are unable to contract fully. They gradually lose elasticity. Holes develop in the lung tissue. This reduces the lungs' ability to exchange oxygen for carbon dioxide.

Your breathing may become labored and inefficient. You may feel breathless most of the time.

You are more likely to develop emphysema if you:

  • Smoke
  • Are exposed to secondhand smoke
  • Are exposed to airborne irritants or noxious chemicals:
    • Lead
    • Mercury
    • Coal dust
    • Hydrogen sulfide
  • Live in an area with significant air pollution

Some people have an inherited form of emphysema. The lungs lack a protective protein called alpha-1 antitrypsin. In people with alpha-1 antitrypsin deficiency, lung damage can appear as early as age 30.


People with COPD commonly have symptoms of both chronic bronchitis and emphysema.

Chronic Bronchitis
Chronic bronchitis may have different symptoms in different people.

Your first symptom may be a morning cough that brings up mucus. At first it may only occur during the winter months. In milder cases, a cough produces only a small amount of thin, clear mucus. In other people, the mucus is thick and discolored.

As the illness progresses, the cough begins to last throughout the day and year. It produces more mucus. Symptoms similar to asthma may develop. These include wheezing and shortness of breath.

Eventually, you may develop:

  • A continuous cough
  • Breathlessness
  • Rapid breathing
  • A bluish tint to the skin from lack of oxygen

Over time, the airways narrow. Blood pressure increases in the arteries that feed the lungs. This strains the right side of the heart. Eventually, heart failure may develop. Blood backs up in the liver, abdomen and legs.

Chronic bronchitis also makes you prone to frequent respiratory infections. It increases the risk of potentially life-threatening breathing difficulties. These often require hospitalization.

If you have emphysema, you may first feel short of breath during activities such as walking or vacuuming. Lung function decreases slowly in emphysema. You may hardly notice the change as breathing becomes more and more difficult.

With time, you may develop:


Your doctor will examine you. He or she will look for evidence of COPD, including:

  • Rapid breathing
  • A bluish tint to your skin, lips or fingernails
  • A distended, barrel-shaped chest
  • Use of neck muscles to breathe
  • Abnormal breath sounds
  • Signs of heart failure (swelling in the ankle and legs)

The evaluation of COPD often includes some of the following tests:

  • Blood oxygen level — The medical assistant puts a clip on your finger for less than a minute. It is painless. The device measures the oxygen level in your blood (called the oxygen saturation level).
  • Pulmonary function test — You will breathe into a special mouthpiece. A machine will measure how much your airways are blocked and how much your lungs inflate.
  • Blood tests — Blood tests measure the different types of blood cells. They also measure the amount of oxygen and carbon dioxide in the blood.

If your doctor suspects inherited emphysema, blood tests can check for low alpha-1-antitrypsin levels.

  • Chest X-rays and CT chest scans — The images provide a baseline, showing the extent of damage. They can very helpful in the future if you develop new symptoms. Comparing new X-rays or CT scans to the old images makes it easier for your doctor to diagnose a new pneumonia or a possible lung cancer. They also show whether your heart is enlarged.
  • Electrocardiogram — Measures the electric activity of the heart. It is usually done to make sure your symptoms are not caused by a heart problem rather than a complication of COPD.
  • Sputum analysis — If you have symptoms suggestive of bronchitis or pneumonia, you may be asked to cough up a sample of sputum (mucus). The sample is sent to the lab to look for bacteria.

If you are diagnosed with inherited emphysema, family members should be tested for alpha-1-antitrypsin deficiency.

Expected Duration

Symptoms of chronic bronchitis tend to begin in smokers after age 50. These symptoms gradually worsen for the rest of the smoker's life unless he or she quits smoking.

Most cases of emphysema are diagnosed in smokers in their 50s or 60s. People with the inherited form can show symptoms as early as age 30. Regardless of the cause, emphysema has no cure and lasts a lifetime.


The majority of cases of COPD are related to smoking You can drastically reduce your risk of COPD by avoiding cigarettes.

  • If you smoke, get the help you need to stop.
  • If you don't smoke, don't start.
  • Limit your exposure to secondhand smoke.

In addition, avoid outdoor activities when air pollution levels are high.

If you have chronic bronchitis, avoid contact with anyone with an upper respiratory tract infection. Even a mild cold can trigger a flare-up of bronchitis symptoms.

During cold and flu season:

  • Wash your hands frequently
  • Avoid touching your face with your hands

Anyone with COPD should be vaccinated against influenza and pneumococcal pneumonia.


No treatment can fully reverse or stop COPD.

Treatment aims to:

  • Relieve symptoms
  • Treat complications
  • Minimize disability

The first step in treatment is to quit smoking. This is the most critical factor for maintaining healthy lungs.

Quitting smoking is most effective during the early stages of COPD. Doing so can reverse some early changes. And it can also slow the rate of decline of lung function in later stages.

Other COPD treatments may include:

  • Environmental changes — Your COPD may be caused by work-related exposure to dusts or chemicals. You and your doctor should discuss how to change your work environment.

    People with COPD should avoid exposure to outdoor air pollution and secondhand smoke. Also avoid other airborne toxins, such as deodorants, hair sprays and insecticides.
  • Medications — Doctors generally prescribe bronchodilators. These medications open up the airways. They may be taken as an inhaled spray or in pill form.

    Antibiotics may be necessary to treat acute respiratory infections.

    Daily inhaled corticosteroids can reduce airway inflammation. For flare-ups, an oral corticosteroid called prednisone often is prescribed.

    For severe disease, your doctor may also prescribe either azithromycin or roflumilast. Azithromycin is an antibiotic that has other properties that may help reduce the frequency of flare-ups. Roflumilast may decrease inflammation and tightness in the airways.
  • Exercise programs — Regular exercise builds stamina. It will improve your quality of life, even if it does not directly improve lung function. Pulmonary rehabilitation programs can reduce the need for hospitalization.
  • Good nutrition — A balanced diet can help maintain stamina and improve resistance against infection. Drinking enough fluids can help keep mucus watery and easy to drain.
  • Supplemental oxygen — Your lungs may not be getting enough oxygen into your blood. Oxygen therapy can:
    • Improve your quality of life
    • Increase your ability to exercise
    • Help to relieve heart failure
    • Prolong life
    • Improve mental function
    • Lift your spirits
  • Lung volume-reduction surgery — An option for some carefully selected patients with emphysema. This surgery removes the most severely diseased portions of the lungs. This allows the less damaged areas to expand better. The long-term value of this procedure is unknown.
  • Lung transplants or heart-lung transplants — Transplants are rarely an option, except in very selected cases of early onset, severe COPD.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

View more treatment options

When To Call A Professional

See your doctor annually to check for early signs of lung disease if you:

  • Smoke
  • Work in a job that carries a high risk of COPD

You should be tested for alpha-1 antitrypsin deficiency if you have family members with the problem. If you have alpha-1 antitrypsin deficiency, have your breathing monitored regularly for early signs of emphysema.

Call your doctor whenever you have:

  • Shortness of breath
  • A chronic cough with or without phlegm
  • A significant decrease in your usual ability to exercise


There is no cure for COPD. Do the following to improve your function and sense of well-being:

  • Quit smoking
  • Stick to your treatment program
  • Exercise daily

People with COPD who continue to smoke can expect progressive deterioration of lung function. Quitting completely is the best chance of stopping or slowing down the process.

It is never too late to quit. Even with severe chronic bronchitis, symptoms can improve.

The lung damage from emphysema cannot be reversed. However, quitting smoking can decrease the risk of additional harm to the lungs.

Additional Info

American Lung Association

National Heart, Lung, and Blood Institute (NHLBI)


Learn more about Chronic Obstructive Pulmonary Disease

Treatment options

Care guides guides (external)

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.