Respiratory sounds

Air makes sounds when you breathe.

You can hear these sounds. They can be soft or loud. Some sounds are high. Other sounds are low.

Doctors use a tool to listen. This tool is a stethoscope. It helps them hear your lungs well.

Sometimes, breaths sound different. A breath might sound like a whistle. It might sound like a click. It could even sound like a snore.

These sounds happen when air moves. Air moves through your tubes. It moves through your lungs.

Listening helps doctors know you are well. It is a way to check your body.

Air makes sounds as it moves through your body. These are called respiratory sounds. You can hear them with your own ears. Doctors also use a tool called a stethoscope. This tool helps them listen to your lungs.

Doctors look at two things. They check the pitch. Pitch is how high or low a sound is. They also check the intensity. Intensity is how loud or soft a sound is. Normal sounds change based on where they are heard. Some are very loud and high. Others are soft and low.

Sometimes, people make extra sounds. We call these added sounds. A wheeze is a high whistling sound. It often happens when airways are narrow. Crackles are small clicking or rattling sounds. These happen when air opens tiny parts of the lungs. Some sounds can sound like snoring. We call these rhonchi. Other sounds might sound like a gasp or a whoop. Doctors listen closely to find these sounds. This helps them learn how your lungs are working.

Every time you breathe, air moves through your body. This movement creates specific noises called respiratory sounds. You can hear these sounds with your own ears. Doctors often use a stethoscope to listen more closely. This tool helps them hear sounds deep inside the lungs.

Listening to these sounds helps doctors learn about health. They look at the pitch of the sound. Pitch is how high or low a sound is. They also check the intensity. This means they note if a sound is soft or loud.

Doctors listen to two parts of the breath cycle. They listen when you breathe in and when you breathe out. They check the pitch using numbers called hertz. A low pitch is 200 hertz or less. A high pitch is 400 hertz or more. The sounds change based on where they are heard. For example, tracheal sounds are very loud. These are heard over the trachea. Bronchial sounds are loud and high pitched. They are heard over the manubrium.

Sometimes, the body makes added sounds. These are not part of normal breathing. One type is a wheeze. A wheeze is a high whistling sound. It happens when airways are narrow. Another sound is called a crackle. Crackles sound like small clicks or rattles. They happen when air opens tiny parts of the lungs. Some sounds are called rhonchi. These sound like snoring. They are caused by secretions in the airways.

Other sounds include stridor or a loud gasp.

People have studied these sounds for a long time. In 1957, two people named Robertson and Coope studied them. They suggested two main groups for added sounds. They called them "continuous" and "interrupted." Later, in 1976, the International Lung Sound Association helped. They made the categories even simpler. They grouped sounds into wheezes, rhonchi, and crackles. This helped doctors use the same names.

This work makes it easier to understand lung health.

Doctors use special tests to check these sounds. They might use a test called egophony. In this test, a person says a long "E" sound. If the lungs have fluid or a tumor, the sound changes. The "E" sound might sound like an "A" sound instead. They also use a test called whispered pectoriloquy. A person whispers a two-syllable number. Normally, a doctor cannot hear this over the lungs. If they do hear it, it shows something is different.

These tests show how sound moves through the body.

Respiratory sounds are the specific noises made by air moving through the respiratory system. These sounds are often called lung sounds or breath sounds. Clinicians listen to these sounds to understand how a person's breathing is functioning. They can hear these sounds directly with their ears or through auscultation. Auscultation is the medical act of listening to sounds from the body. This is usually done using a stethoscope over the lung fields. By studying the spectral characteristics of these sounds, medical professionals can learn a great deal about health.

When assessing these sounds, clinicians focus on two main properties: pitch and intensity. Pitch describes how high or low a sound is. It is measured in hertz (Hz). A low pitch is typically 200 Hz or less, while a high pitch is 400 Hz or more. Intensity describes the volume, ranging from soft and medium to loud or very loud. Doctors also observe the breath cycle. They listen during the inspiratory phase, which is breathing in, and the expiratory phase, which is breathing out. Noting the duration of the sound during these two phases provides vital information.

Normal breath sounds are categorized by where they are heard in the body. Tracheal sounds are heard over the trachea and are very loud. In these sounds, the expiratory duration is equal to the inspiratory duration. Bronchial sounds are heard over the manubrium and are loud and high-pitched. For these, the expiratory phase lasts longer than the inspiratory phase. Bronchovesicular sounds are heard between the first and second intercostal space or between the scapulae. These have an intermediate intensity and similar durations for breathing in and out. Finally, vesicular sounds are heard over most of the lungs. These are soft, low-pitched, and the expiratory phase is shorter than the inspiratory phase.

Sometimes, the body produces adventitious sounds, which are added or abnormal sounds. These are often divided into continuous and discontinuous types. Continuous sounds last approximately 250 ms or longer. Examples include wheezes, which are high-pitched whistling sounds caused by narrowed airways. Rhonchi are lower-pitched, coarse rattling sounds that resemble snoring. These are often caused by secretions in the bronchial airways. Stridor is another continuous sound that is high-pitched and whistling. It usually occurs due to a blockage in the trachea or the back of the throat. An inspiratory gasp, like the "whoop" in pertussis, is also a continuous high sound.

Discontinuous sounds are also common and are defined as discrete sounds lasting less than 250 ms. Crackles, or rales, are a major type of discontinuous sound. They can be fine or coarse and often sound like clicking, bubbling, or rattling. These may occur when air opens the alveoli, which are tiny air sacs in the lungs. A pleural friction rub is another discontinuous sound. It consists of many repeated rhythmic sounds caused by inflammation of the lung linings. There is also Hamman's sign, which is a discontinuous crunching or rasping sound. This is related to the heartbeat and occurs during pneumomediastinum or pneumopericardium. Grunting is a low-pitched, continuous expiratory sound often linked to surfactant deficiency.

The way we classify these sounds has changed over time. In 1957, researchers Robertson and Coope proposed two main categories for adventitious sounds. They called them "continuous" and "interrupted" sounds. Later, in 1976, the International Lung Sound Association simplified these categories. They established that wheezes are continuous sounds above 400 Hz. They defined rhonchi as continuous sounds below 200 Hz. They also categorized crackles into fine and coarse types. This standardized system helps clinicians communicate clearly about what they hear.

Clinicians also use special tests involving vocal resonance to find disease. Vocal resonance is how sound travels through different tissues. In whispered pectoriloquy, a patient whispers a two-syllable number. Normally, a doctor should not hear this over the lungs. If the whisper is audible, it may indicate pulmonary consolidation, where lung tissue becomes denser. In egophony, a patient says a long "E" sound. If the lungs contain fluid or a tumor instead of air, the sound changes. The high frequencies diminish, making the "E" sound appear to be an "A" sound. These tests show how sound moves differently through air versus solid or fluid media.