Health
Fact-checked

At WiseGEEK, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.

Learn more...

What are Korotkoff Sounds?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

Korotkoff sounds are distinctive sounds that can be distinguished when a blood pressure cuff is applied and adjusted. They were first described in 1905 by Russian physician Nikolai Korotkoff. Listening for these sounds with a stethoscope while using a blood pressure cuff allows a health practitioner to take a blood pressure reading. Many people are familiar with the process of manually taking blood pressure in clinical settings, as blood pressure is a vital sign commonly tested at doctor visits.

Under normal conditions, the movement of blood through the artery in the arm is not audible. This is because the flow of blood is not turbulent. In people with artery disease, sounds can be heard as the flow is disrupted. When a blood pressure cuff is applied, it disrupts the flow of blood in a stable and predictable fashion, and this can be used to generate information about the patient's blood pressure.

Improper placement of a stethoscope may interfere with Korotkoff sounds.
Improper placement of a stethoscope may interfere with Korotkoff sounds.

When a blood pressure cuff is inflated above the systolic blood pressure, no sounds can be heard. The flow of blood is occluded and thus it is not moving through the artery in the arm at all. As pressure is lowered, the first phase of the Korotkoff sounds, a sharp tapping noise, is heard as the blood starts to woosh back into the artery. The reading on the cuff at this point is equal to the systolic blood pressure. As the pressure falls, the blood moves into the second stage, a swishing noise, followed by the third stage, characterized by pounding as blood moves through the vessel.

Under normal circumstances, the movement of blood through the arm's artery is inaudible.
Under normal circumstances, the movement of blood through the arm's artery is inaudible.

The fourth phase in the Korotkoff sounds is a blowing noise, followed by silence in the fifth phase as the pressure equals that of the diastolic pressure. The flow of blood returns to normal without the pressure of the blood pressure cuff, and silence resumes. A skilled practitioner can get an accurate blood pressure reading with one session, while others may take a second reading to confirm. Completely electronic blood pressure reading machines are programmed to listen for the Korotkoff sounds and take readings as appropriate.

In people with artery disease, sounds can be heard as the flow of blood is disrupted.
In people with artery disease, sounds can be heard as the flow of blood is disrupted.

Things which can interfere with the Korotkoff sounds can include placing the stethoscope improperly or being in a noisy environment. Patients also need to follow directives from the health care provider, including staying still and relaxed to avoid accidentally increasing their blood pressure. Talking or moving during the test can disrupt the readings and force the health care provider to repeat the test.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon329392

@panda: Your heart is a bit weak. Just letting you know. D you have a tendency to faint? You say your normal blood pressure is pretty low? What is it?

billr

When I was told that one shouldn't talk while using an automatic blood pressure reading machine, I thought -- mistakenly, according to the article -- that the "activity" of talking might raise one's actual blood pressure and thereby result in a too-high BP reading. It was very interesting to find out from this article the real reason for the "ban" on talking.

anon189506

@panda2006: Make certain that there is a prominent note in your medical records that you have low blood pressure. The medical community can misunderstand your condition in an emergency or otherwise if that information is missing.

When I had an operation over 30 years ago, the nurses almost "called a code" on me because my normally low blood pressure was even lower in the middle of the night after the day of anesthesia and pain medications. I had to assure them that I would not be responding to them by conversation if I were in dire straits.

panda2006

When doctors or nurses try to take my pulse or blood pressure on my wrist, they often have trouble hearing the sounds. I think this probably is because I have pretty low blood pressure, both naturally and even more now that I am a runner.Usually once they can find it, it's fine and I don't have any other signs of a serious problem, but it still can be a little creepy when someone at the doctor's office can't find my pulse.

Post your comments
Login:
Forgot password?
Register:
    • Improper placement of a stethoscope may interfere with Korotkoff sounds.
      By: Iurii Sokolov
      Improper placement of a stethoscope may interfere with Korotkoff sounds.
    • Under normal circumstances, the movement of blood through the arm's artery is inaudible.
      By: Monkey Business
      Under normal circumstances, the movement of blood through the arm's artery is inaudible.
    • In people with artery disease, sounds can be heard as the flow of blood is disrupted.
      By: Alexandr Mitiuc
      In people with artery disease, sounds can be heard as the flow of blood is disrupted.