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 four 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, and 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. They are most often heard when a person breathes out (exhales). Wheezing and other abnormal sounds can sometimes be heard without a stethoscope.
When to Contact a Medical Professional
Seek immediate medical care if you have:
- Nasal flaring
- Cyanosis (bluish discoloration of the skin)
- Severe trouble breathing or shortness of breath
Contact your health care provider if you have wheezing or other abnormal breathing sounds.
Your health care 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 health care provider usually discovers abnormal breath sounds. You may not even notice them.
The following tests may be done:
Lung sounds; Breathing sounds
Kraft M. Approach to the patient with respiratory disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 83.
Update Date 5/13/2013
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.