People who have chronic obstructive pulmonary disease (COPD) usually have some symptoms of both chronic bronchitis and emphysema. Your symptoms will change depending on the severity of your COPD.

Key symptoms include:

• Long-term (chronic) cough.
• Chronic mucus (sputum) production when you cough.
• Repeated episodes of acute bronchitis.
• Shortness of breath that is persistent and gets worse, occurs during exercise, and gets worse during respiratory infections, such as colds.

You may have a rapid, sometimes sudden, and prolonged worsening of symptoms (cough, amount of mucus, and/or shortness of breath), especially if your COPD is mainly chronic bronchitis. This is called a COPD exacerbation. A COPD exacerbation can be life-threatening, and you may have to go to the hospital.

A number of medical organizations have classified COPD according to symptoms and lung function. Lung function is based on spirometry tests that measure how much air you can breathe out compared to a person without COPD (the predicted value). The specific tests used evaluate how much air you can breathe out in one second (forced expiratory volume, or FEV1) and the amount of air you can breathe out after taking a deep breath (forced vital capacity, or FVC).

The guidelines are all similar. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) uses the following classifications:

At risk for COPD

You are at risk for COPD if you have risk factors, such as smoking, and you have long-term (chronic) cough and mucus production. People at risk for COPD have normal lung function, as measured by FEV1.

Mild COPD (stage 1)

Symptoms of mild COPD include a usually, but not always, chronic cough that often brings up mucus from the lungs.

People with mild COPD have impaired lung function, as measured by a FEV1 of 80% or more of predicted value. You may have no shortness of breath and may not know you have impaired lung function until a lung test is done.

Moderate COPD (stage 2)

In moderate COPD, you have some of the symptoms of stage 1, plus you may have:

• A chronic cough that is getting worse and that brings up a large amount of mucus from the lungs.
• Shortness of breath and fatigue with exercise and strenuous daily activities.
• An occasional COPD exacerbation, which is a rapid, sometimes sudden, worsening in your usual shortness of breath or in other symptoms.

People with moderate COPD have a FEV1 of 50% to 79% of predicted value. Early symptoms of COPD often are overlooked or considered part of getting older.

Severe COPD (stage 3)

In severe COPD, you have some of the symptoms of stages 1 and 2, plus you may have:

• Shortness of breath with even simple daily activities, such as getting dressed and eating.
• Weight loss.
• Repeated and sometimes severe COPD exacerbations that have an impact on your life.