Lung Sounds: What Do They Mean?

Medically Reviewed by Zilpah Sheikh, MD on July 21, 2024
Written by Rachel Reiff Ellis, Lori M. King, PhD
8 min read

When you go for a sick visit or your annual checkup at your doctor's office, they will likely listen to your chest through a stethoscope. Part of what they're listening for is the sounds your lungs make as you breathe in and out. Listening to your lung sounds gives your doctor a clue about how well your lungs are working.

There are three types of normal lung sounds that are different depending on where in your chest your doctor is listening. The three normal lung sounds are bronchial, bronchovesicular, and vesicular.

Bronchial lung sounds

Your doctor can hear these most clearly when you breathe out. They'll listen high in your chest and over your windpipe for loud, rough, and high-pitched lung sounds. These sounds are normal in your bronchial area, but may be abnormal in other areas of your lungs.

Bronchovesicular lung sounds

Your doctor can hear these sounds when you breathe in and out. They'll listen in the middle part of your chest for sounds are lower-pitched than bronchial lung sounds but higher-pitched than vesicular lung sounds.

Vesicular lung sounds

Your doctor can hear these sounds best when you breathe in. They'll listen in your mid-back for soft, smooth, low-pitched sounds. These tell your doctor that nothing (like mucus) is blocking your airways, and there's no swelling or narrowing that's stopping you from taking a full breath.

Adventitious lung sounds

Adventitious sounds are ones that your doctor hears in addition to the normal sounds. These noises can help your doctor identify problems in your lungs. For instance, lung conditions like bronchitis or pneumonia can cause adventitious lung sounds. The five most common abnormal lung sounds are:

  • Wheezing
  • Rales (also called crackles)
  • Stridor
  • Rhonchi or rhonchus
  • Pleural rub

Read on to learn more about these common types of adventitious lung sounds and a few less common ones.

A wheeze (or sibilant rhonchus) is a continuous, high-pitched lung sound. Wheezing may be easier to hear when you breathe out, but sometimes you can hear it when you’re breathing in and out. You may even be able to hear wheezing without a stethoscope. Wheezing indicates you have a narrowed airway that limits the flow of air in and out of your lungs. 

Wheezing causes

The most common causes of wheezing include:

  • Asthma, which is a lung disease that makes your airways swollen, narrow, and blocked by excess mucus
  • Chronic obstructive pulmonary disease (COPD), which is a group of long-term, inflammatory lung conditions that limit airflow in your lungs. Some examples include emphysema and chronic bronchitis.
  • Cystic fibrosis, which is a condition where thick mucus clogs your airways and makes it difficult to breathe.
  • Upper respiratory infections, such as pneumonia or infections caused by bronchiolitis and respiratory syncytial virus (RSV)
  • Tumors in your lungs
  • Breathing something into your lungs or getting an object stuck in your windpipe.
  • Vocal cord dysfunction, which makes your vocal cords close instead of open when you breathe. This makes it harder to get air into and out of your lungs.
  • Chronic acid reflux can cause the valve that connects your esophagus and stomach to loosen. This lets stomach acid get into your esophagus and windpipe, which may cause wheezing.
  • Allergies and severe allergic reactions (anaphylaxis)
  • Sleep apnea, which is a sleep breathing disorder that may cause you to stop breathing periodically while you're asleep.

You can also start wheezing if you smoke or as a side effect of some medications (such as aspirin if you have asthma). 

 

Rales, or crackles, are discontinuous, interrupted, or explosive lung sounds. They may sound like pulling velcro open. The sounds can be short and high-pitched, or they may last a bit longer and be lower-pitched. Your doctor is more likely to hear crackles when you’re breathing in, but they may happen when you breathe out, too. Rales happen when your airway snaps open as you breathe in.

Rales causes

Common causes of short, high-pitched rales (fine crackles) include:

  • Pneumonia, which is an infection in your lungs. It causes your lung tissues to swell and may cause fluid or pus to build up in your airways.
  • Congestive heart failure, which is a long-term condition where your heart can’t pump blood well enough to meet your body’s needs. Because your blood isn't circulating fast enough, it builds up in other parts of your body, usually your lungs, legs, and feet.
  • Interstitial lung disease, which is a group of long-term, inflammatory lung conditions that cause scarring in your lungs. It can be caused by certain medications, radiation therapy, connective tissue diseases, or inhaling harmful substances, like asbestos.

Longer, low-pitched rales (coarse crackles) are caused by the same conditions as fine crackles but suggest a more advanced state of the condition. 

 

 

Stridor is a continuous, rough, high-pitched whistle or squeaking lung sound. Your doctor is more likely to hear it when you breathe in. Like wheezing, stridor suggests you have blocked airflow, but it happens more in your upper airway or throat than in your chest.

Stridor causes

Causes of stridor include:

  • An upper airway infection, especially in kids. Your doctor may call this viral croup.
  • Swelling in your throat from tonsillitis or epiglottitis, which is when the “lid” of cartilage that covers your windpipe swells and blocks your airflow.
  • An object stuck in your windpipe
  • Injury to your windpipe
  • A tumor in your voice box
  • An allergic reaction
  • A pocket of pus (abscess) in your throat
  • Vocal cord dysfunction or paralysis
  • Inhaling smoke or chemicals

Rhonchi (also called sonorous rhonchi) are loud, continuous, low-pitched, snoring, or gurgling lung sounds. Your doctor may be able to hear them best when you’re breathing out, but they may also hear them when you breathe in and out. The sound might move around to different parts of your chest when you cough as mucus moves around. These sounds happen because your larger airways are narrowed by mucus, and they flutter as air flows through.

Rhonchi causes

Wheezing and rhonchi have a similar cause (narrowed airways usually due to fluid buildup), so the causes are mostly the same. For instance, rhonchi is often caused by:

  • Pneumonia
  • COPD
  • Cystic fibrosis

Pleural rub is a rough, scratching, or grating lung sound. Your doctor will hear it when you breathe in and out. It's usually louder than other lung sounds since it's happening in your chest wall. You get pleural rub when the linings of your lungs (pleura) swell and rub against each other. 

Pleural friction rub causes

Possible causes of pleural rub include:

  • Viral or bacterial infections, such as those caused by the flu or pneumonia
  • Autoimmune diseases, such as lupus or rheumatoid arthritis
  • Lung or pleural conditions, such as mesothelioma, tuberculosis, or asbestosis
  • Chest surgery or trauma
  • A blood clot in your lung (pulmonary embolism)
  • Inflammatory bowel disease
  • Sickle cell disease
  • Certain medicines, such as hydralazine, isoniazid, or procainamide

Whooping is a loud, high-pitched gasp lung sound. You may make this noise when you gasp for air after a coughing fit. You will be able to hear this when you breathe in as you fill your lungs after expelling all your air when coughing. 

Whooping causes

The most common cause of whooping lung sounds is an infection with a bacteria called Bordetella pertussis, commonly called whooping cough. 

Hamman's sign is a crunchy or scratchy lung sound that happens in time with your heartbeat. This sound indicates that you have air trapped in the space between your lungs (a medical condition called pneumomediastinum). The sound is caused by shifting of the trapped air from the movement of your heart as it beats.

Hamman's sign causes

The most common causes of pneumomediastinum include:

  • Severe injury to your chest
  • Surgery to your chest
  • Rupture to the small structures in your lungs, called alveoli
  • A tear in your airway or your gastrointestinal (GI) tract
  • Infection in your chest from bacteria, fungi, or viruses
  • Things that suddenly increase the pressure in your chest, such as coughing, sneezing, or vomiting
  • Straining while pooping
  • Pushing during childbirth
  • Inhaling recreational drugs
  • Scuba diving
  • Mechanical ventilation, for instance during surgery

 

Infants with breathing problems may make persistent noises, such as:

  • A hoarse cry and a "barking" cough. This may mean your baby has croup, which is an infection of the voicebox, windpipe, and bronchial tubes.
  • Stridor. This may come from extra tissue around their voice box (laryngomalacia). It may be worse when your baby lies on their back. They usually grow out of this by the time they're 2 years old.
  • Rales. This may be an indication that your baby has pneumonia.
  • Wheezing and a deep cough. This may suggest that your baby has a block in their airway.

 

Your doctor can get important information about the health of your lungs by listening closely as you breathe. The easiest and most common way to do this is to hold a stethoscope to the skin on your back and chest. This is called auscultation.

As your doctor listens, they’ll ask you to take deep breaths through your mouth. They also may ask you to speak certain phrases and see how they sound through your chest or back. Some examples of this include:

Bronchophony

Your doctor will ask you to say “ninety-nine.” Normally, your lungs will muffle the words. If the words sound clear through the stethoscope, it may be a sign that your lungs are filled with blood, fluid, or mucus.

Whispered pectoriloquy

This involves whispering “ninety-nine” or “one, two, three.” Healthy lungs will dampen the sound and make the words faint, but they’ll be louder if your lungs are filled with fluid.

Egophony

If you have fluid in your lungs, your doctor uses this test to check for a collapsed lung. As you say an “e” sound, your doctor will listen to see if it’s muffled and sounds like “e” or if it’s louder and sounds like “a,” which means fluid is changing the sound.

 

If you notice you have abnormal or changes in your breathing sounds, you should go get checked out by your doctor.

And if you have any of the following symptoms, call 911 and get to the ER right away:

  • Bluish discoloration of your skin 
  • Nasal flaring
  • Severe trouble breathing or shortness of breath
  • You start wheezing suddenly after a bug bite or after eating a food you may be allergic to

 

As part of your physical exam, your doctor will listen to your lung sounds through a stethoscope. Part of what they are listening for is adventitious lung sounds, which are sounds your lungs make in addition to your normal breathing sounds. The five major adventitious lung sounds are wheezing, rales, stridor, rhonchi, and pleural rub. Various conditions cause different sounds, although there can be overlap. Lung sounds are one clue your doctor uses to help them figure out what is causing you to have breathing problems.

What lung sounds does pneumonia have?

This depends on whether you have viral or bacterial pneumonia. Bacterial pneumonia tends to be more severe than viral pneumonia. People with bacterial pneumonia can have wheezing, rales, rhonchi, and pleural rub. People with viral pneumonia may only have a dry cough.

What do congested lungs sound like?

Congestion in your lungs is usually due to mucus or swelling. If you have congestion, you may have wheezing, rales, rhonchi, and pleural rub.