Lung sounds are one of the things your provider listens for when they use a stethoscope on your chest or back. Air flowing smoothly through your airways creates normal (vesicular) lung sounds. Swelling, blockages or mucus in your airways can create abnormal lung sounds. These include rhonchi, wheezing, stridor, crackles (rales) and pleural rub.
Lung sounds, or respiratory sounds, are the noises your healthcare provider can hear in your airways (passages in your lungs) when you breathe in and out. When a provider examines you, they often use a stethoscope to listen to and evaluate (or auscultate) your lungs.
When your lungs are clear — without swelling, mucus or blockages — your breathing sounds smooth and soft. Many diseases and conditions can cause abnormal, or adventitious, lung sounds. These might be crackling, whistling, gurgling or other noises.
A provider can’t diagnose you based only on lung sounds. They’ll use other information, like your other symptoms, health history and additional tests, to understand what might be causing the sounds. Causes of abnormal lung sounds can be temporary and minor, like bronchitis, or potentially serious, like pneumonia.
You might hear providers describe lung sounds as:
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Lungs that are functioning normally create a smooth, soft sound you can hear when you breathe in and out. They’re also called vesicular lung sounds. Vesicular lung sounds usually mean nothing is blocking your airways, and they’re fully open (not narrowed or swollen).
The most common abnormal (adventitious) lung sounds include:
Rhonchi (plural of the word rhonchus) are continuous, low-pitched sounds that are best heard when you’re breathing out (also called “expiration”). The sound might move around to different parts of your chest when you cough, moving mucus around. The sound is sometimes described as snoring or gurgling. It’s sometimes called “sonorous rhonchus.”
A wheeze is a continuous, high-pitched hissing sound. It’s sometimes called “sibilant rhonchus.” It’s more commonly heard when you breathe out, but sometimes you can hear a wheeze both when you’re breathing in and out, especially if you have asthma.
Stridor is a continuous, harsh, high-pitched whistle or squeaking sound. Providers usually hear it when you breathe in (also called “inspiration”).
Crackles, also called rales, are described as discontinuous, interrupted or explosive sounds. They might sound like rattling, bubbling or clicking. Fine crackles, or “crepitation,” are short, high-pitched sounds. Coarse crackles are a lower pitch and last longer. A provider is more likely to hear crackles when you’re breathing in.
Pleural rub is a rough, grating sound of the lining of your lungs (pleurae) rubbing against each other. Providers hear it both when you breathe in and breathe out.
Anything that narrows or blocks your airway can cause abnormal lung sounds. This keeps the air from flowing smoothly, creating vibrations and other noises. The most common causes of abnormal lung sounds include:
Diseases and conditions that can cause abnormal lung sounds include:
The types of sounds your healthcare provider hears can help them diagnose diseases or learn more about your condition. For instance, they’re more likely to hear wheezing if asthma narrows your airways. But they’re more likely to hear stridor in a child with croup or if you have an airway blocked by swelling, a foreign object or a tumor.
Where mucus or a blockage is located in your airways can also cause different sounds. For instance, mucus in your larger airways can cause rhonchi. Mucus in your small airways is more likely to cause crackles.
A provider will use your symptoms and any abnormal lung sounds they hear to help make a diagnosis. They may also need to order additional tests. How they treat you will depend on what’s causing the abnormal sounds. Some treatments might include:
If an ongoing condition, like asthma or allergies, causes abnormal lung sounds, you may be able to prevent them by managing your condition. You can reduce your risk of respiratory infections by washing your hands and taking other steps to prevent the spreading of infectious diseases. Some causes of abnormal lung sounds can’t be prevented.
Talk to a healthcare provider if you have concerns about sounds you hear when you breathe. If you have noisy breathing and are having trouble breathing, go to the nearest emergency room.
A note from Cleveland Clinic
Crackling, rattling, clicking or whistling — there are lots of words to describe lung sounds. Their differences can give your provider important clues about what’s happening inside your chest. Some causes of abnormal lung sounds are temporary and not cause for concern. Others can be serious. Your provider will use your other symptoms and, sometimes, additional tests to understand what abnormal sounds might mean. Then you can make a plan together to treat or manage the underlying condition.
Last reviewed by a Cleveland Clinic medical professional on 08/04/2023.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy