According to the U.S. Centers for Disease Control and Prevention, more than 12 million Americans are living with chronic obstructive pulmonary disease (COPD), a progressive lung disease that causes breathing difficulties and can turn fatal. Another 12 million people may have COPD but don’t even know it.

Chronic Obstructive Pulmonary Disease (or COPD) often results from smoking, or a common cold, or flu-like illness. COPD occurs when the airways in your lungs become inflamed due to excess mucus build-up. As a result the airways become blocked and oxygen intake is depleted.

An awareness of the early warning signs of COPD can be the first step to prevent the condition from worsening. If left untreated, COPD can turn into a viral or bacterial lung infection, or result in the complete loss of lung function.

If you have one or several of the following COPD symptoms, seek medical attention immediately:

Shortness of breath—particularly following physical activity


Do you avoid some everyday activities for fear of becoming short of breath? Shortness of breath is an early COPD symptom. In fact, it’s the major COPD warning sign, says pulmonologist Barry Make, MD, professor of medicine in pulmonary sciences and critical care medicine at the University of Colorado Denver and director of respiratory care at National Jewish Medical and Research Center. Breathlessness occurs when it takes more work for your lungs to move air in and out. You might find yourself running out of breath when you’re climbing stairs or walking to your car, but it’s also possible to be short of breath when you’re not doing anything at all. Even if it happens only occasionally, talk to your doctor.

You Notice Changes in Your Mucus


Producing lots of mucus (also called sputum or phlegm) that comes from your lungs, not your sinuses, could be a warning sign of COPD, Dr. Make says. Your lungs need mucus to keep your airways moist, but noticeable changes in your mucus could be a COPD symptom. Look for an increase in the amount of mucus produced, or a change in its texture or color — especially if it’s yellow or green, and you see blood in it.

You Cough for No Apparent Reason

Mandatory Credit: Photo by Garo/Phanie / Rex Features (714239bu) Model released - Woman coughing. Various - 2007

Another common COPD symptom is a worsening cough — one that doesn’t go away or doesn’t seem to have a cause like a respiratory infection. If you’ve been coughing constantly for a few weeks or longer, talk to your doctor about it. A constant cough or a cough with no other signs of a cold or flu could be attributed to either of the two primary COPD diseases, chronic bronchitis and emphysema.

You Wake Up With Head Pain

Senior woman suffering from neck pain with eyes closed in the medical office

Is your head pounding when you get up in the morning? That could be a warning sign of COPD. When your lungs don’t work properly, you don’t get enough oxygen while you are asleep, and carbon dioxide builds up in your blood. Waking up feeling lightheaded or dizzy could also be a sign of COPD.

Your Ankles Swell


Swollen ankles, feet, or legs can also be a red flag. With COPD, your blood vessels don’t get the oxygen they need to stay healthy, putting a strain on your heart. This strain can cause fluid to build up, making your ankles, feet, or legs swell up. The swelling can also be caused by damage to your lungs. Watch for this COPD warning sign and bring it to your doctor’s attention right away if you see it.

You’re Having Trouble Sleeping


Sleep problems are another early COPD warning sign. Breathing difficulties caused by COPD can be so severe that they wake you up several times through the night. Coughing alone can disrupt your sleep, but so can other conditions that tend to co-occur with COPD, such as sleep apnea and gastric gastroesophageal reflux disease (GERD).

You’re Tired All the Time


Fatigue or exhaustion can be another early COPD warning sign, says pulmonologist Fernando Martinez, MD, professor in the department of internal medicine and director of pulmonary diagnostic services at the University of Michigan Health System in Ann Arbor.Fatigue goes hand-in-hand with breathlessness, so much so that some people may not be able to tell whether they’re fatigued or breathless. If your fatigue is keeping you from doing your regular activities, it could be a COPD symptom, and you should talk to your doctor, says Dr. Martinez.

You Lose Weight for No Reason


Have you lost weight without trying? Unexplained weight loss could be due to COPD. When you have COPD, your lungs have to work harder to allow you to breathe, which requires more calories, Martinez explains. Breathing can burn up to 10 times the calories it does for people without the condition. COPD can also lead to a loss of appetite, which can result in weight loss.

It’s Hard to Breathe When Lying Down


Do you find that you spend nights sleeping in your favorite armchair rather than your bed? Or that, when you are in bed, you need to use more pillows to prop your head and chest up to breathe? If you avoid your bed because breathing is harder when you’re lying flat, you could be experiencing a COPD symptom, and you should talk to your doctor about the discomfort.