Lung sounds; Breathing sounds
Breath sounds are the noises produced by the structures of the lungs during breathing.
The lung sounds are best heard with a stethoscope. This is called auscultation.
Normal lung sounds occur in all parts of the chest area, including above the collarbones and at the bottom of the rib cage.
Using a stethoscope, the doctor may hear normal breathing sounds, decreased or absent breath sounds, and abnormal breath sounds.
Absent or decreased sounds can mean:
- Air or fluid in or around the lungs (such as pneumonia, heart failure, and pleural effusion)
- Increased thickness of the chest wall
- Over-inflation of a part of the lungs (emphysema can cause this)
- Reduced airflow to part of the lungs
There are several types of abnormal breath sounds. The 4 most common are:
- Rales. Small clicking, bubbling, or rattling sounds in the lungs. They are heard when a person breathes in (inhales). They are believed to occur when air opens closed air spaces. Rales can be further described as moist, dry, fine, or coarse.
- Rhonchi. Sounds that resemble snoring. They occur when air is blocked or air flow becomes rough through the large airways.
- Stridor. Wheeze-like sound heard when a person breathes. Usually it is due to a blockage of airflow in the windpipe (trachea) or in the back of the throat.
- Wheezing. High-pitched sounds produced by narrowed airways. Wheezing and other abnormal sounds can sometimes be heard without a stethoscope.
Wheezing can be a normal healthy response to an unhealthy environment. Or, wheezing can be a sign of asthma. I'm Dr. Alan Greene and I want to talk with you for a moment about how to tell the difference, what causes wheezing anyway, and when is it healthy and when is it not. Well to understand that, first let's all take a deep breath together (inhales). When you breathe in, the air comes through your nose or mouth, through the big windpipe and breaks into 2 big bronchi, one into each lung. And from there they break into a whole bunch of little, smaller bronchioles. It's almost like a tree's branches branching out. And those bronchioles are where the wheezing happens. Let's look at a bronchiole. Here's one of those small airways. Now if you happen to walk into a cloud of something that's toxic, your body is going to respond instantly to try to protect you. The first thing that will happen is the muscles around the bronchioles will tighten, will constrict down almost like a boa constrictor, and you get the tight airways. If that toxic cloud is still there, to protect your delicate tissues deep in your lungs, swelling of the lining will happen. Inflammatory stuff to help protect you from those toxins. And if it's still there, still irritating, mucus will begin to be secreted to be able again to capture and protect you from those toxins. That's wheezing. Asthma happens when your airways are hyper-responsive. When they're twitchy. When they're hyper-alert and they respond to something that's not truly dangerous. The problem with that is when your bronchioles are constricted and swollen and has mucus in them, that narrow little opening is hard to breathe through. You have to work to breathe, especially to breath out. And that hard breathing through a narrow passageway is what creates the sound we know as wheezing.
When to Contact a Medical Professional
Seek immediate medical care if you have:
- Cyanosis (bluish discoloration of the skin)
- Nasal flaring
- Severe trouble breathing or shortness of breath
Contact your health care provider if you have wheezing or other abnormal breathing sounds.
Your provider will do a physical exam and ask you questions about your medical history and your breathing.
Questions may include:
- When did the breath sound start?
- How long did it last?
- How would you describe your breathing?
- What makes it better or worse?
- What other symptoms do you have?
The provider discovers abnormal breath sounds in most cases. You may not even notice them.
The following tests may be done:
Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW. Chest and lungs. In: Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW, eds. Siedel's Guide to Physical Examination. 9th ed. St. Louis, MO: Elsevier; 2019:chap 14.
Kraft M. Approach to the patient with respiratory disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 83.
Last reviewed on: 5/6/2019
Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.