Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a progressive lung condition that makes breathing increasingly difficult over time. It stems from damage to the airways and lung tissue, which restricts airflow and reduces how efficiently oxygen moves from the lungs into the blood. The disease develops slowly, and while there is currently no cure, treatments and lifestyle adjustments can help manage symptoms and slow its advance. Early detection and prompt care are advised.

COPD actually encompasses two related disorders: chronic bronchitis and emphysema. Chronic bronchitis involves long-term inflammation of the airways, leading to excess mucus, coughing, and chest discomfort. Emphysema damages the tiny air sacs in the lungs, impairing their ability to transfer oxygen to the bloodstream.

Most people with COPD experience shortness of breath, a persistent cough, wheezing, and reduced ability to exercise. These symptoms can worsen suddenly during flare-ups, often triggered by viral or bacterial infections or exposure to irritants. Individuals with COPD typically have a mix of these symptoms and are prone to other health problems.

The condition arises from several factors, most commonly long-term exposure to lung irritants. The strongest risks include tobacco smoke, air pollution, and workplace dust or chemical fumes.

In some regions, smoke from cooking and heating fuels is a major risk factor, especially for women and young children. Early-life factors—such as respiratory infections, poor nutrition, and physical inactivity—can also increase the likelihood of developing COPD later. Genetics may play a role as well.

Diagnosis is usually confirmed with lung function tests that measure airflow. Although COPD cannot be cured, treatment can greatly improve quality of life. Common approaches include inhaled medications to open the airways, pulmonary rehabilitation to boost fitness and breathing control, and oxygen therapy for advanced cases. Quitting smoking is strongly urged, along with reducing exposure to other lung irritants.

As of 2021, about 213 million people worldwide had COPD. It typically appears after age 35–40, and risk rises with age.

In 2021, it was the fourth leading cause of death, accounting for roughly 5% of all deaths. Nearly 90% of COPD deaths in people under 70 occur in low- and middle-income countries. Death rates are expected to climb due to ongoing exposure to risk factors and an aging population.

Signs and symptoms

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines COPD as a lung condition with multiple causes, marked by long-lasting respiratory symptoms—shortness of breath, cough, and mucus—that can flare up periodically. These symptoms stem from problems in the airways (bronchitis, bronchiolitis) or the small air sacs (emphysema), causing persistent, often progressive airflow obstruction.

Shortness of breath

Shortness of breath is a key symptom, chronic and worsening over time. It is often the most distressing aspect, leading to anxiety and disability. Wheezing and chest tightness may come and go, and chest tightness often follows exertion. People in distress may instinctively sit forward with hands on knees—the tripod position—which can ease breathlessness by stabilizing the shoulders.

Those with advanced COPD may also breathe through pursed lips to improve breathing. Breathlessness frequently reduces physical activity, and low activity levels are linked to worse outcomes. Many people seek treatment only after noticing increased breathlessness and frequent colds. In severe cases, constant tiredness, weight loss, muscle wasting, and loss of appetite can occur.

Cough

A chronic cough is often the first symptom, sometimes producing thick mucus (sputum or phlegm). Coughing up mucus can be intermittent and hard to assess; fewer than 30% of cases have a productive cough. Occasionally, airflow limitation develops without a cough. Symptoms tend to be worse in the morning.

Depending on habits, mucus may be swallowed or spat out. A chronic productive cough lasting more than three months a year for at least two years is called chronic bronchitis, which can appear before airflow restriction is diagnosed. People often downplay symptoms, mistaking them for short-term irritation. In severe COPD, vigorous coughing can cause rib fractures or brief loss of consciousness.

Exacerbations

An acute exacerbation is a sudden worsening of symptoms lasting from days to two weeks. It may involve increased breathlessness, more mucus, a change in mucus appearance, or altered cough or wheeze. A common sign is air trapping—difficulty fully exhaling.

Flare-ups are often driven by inflammation from viral or bacterial infections or airway irritants. Viral infections like the common cold cause about 70% of flare-ups, which are more frequent in winter but can occur anytime. Bacterial respiratory infections also play a role.