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Mahesan Subramaniam: Fun Fact About the Sound of Your Heartbeat

Dato Capt. Dr. Mahesan Subramaniam/LinkedIn

Feb 10, 2026, 15:09

Mahesan Subramaniam: Fun Fact About the Sound of Your Heartbeat

Mahesan Subramaniam, Co-Founder of United Health Tourism, Founder and Chief Executive Officer at TRI International group, posted on LinkedIn:

“Fun fact: the sound of your heart beat is caused by your valves.

Your heartbeat’s iconic ‘lub-dub’ isn’t the muscle moving — it’s the rhythmic closing of the valves ensuring one-way blood flow.

Most people assume the rhythmic ‘lub-dub’ of a heartbeat is the sound of the heart muscle squeezing blood throughout the body. However, that iconic sound is actually the result of the heart’s four valves snapping shut in a perfectly timed sequence.

The first sound, the lower-pitched ‘lub,’ occurs when the atrioventricular valves—specifically the tricuspid and mitral valves—close simultaneously. This happens just as the heart’s lower chambers, the ventricles, finish filling with blood and prepare to pump it out to the rest of the system.

Following the ‘lub’ comes the sharper, higher-pitched ‘dub.’ This second sound is produced by the closing of the semilunar valves at the entrances of the aorta and pulmonary artery. As blood is ejected from the heart, these valves slam shut to prevent any backflow into the chambers.

This mechanical process is far more than just a biological soundtrack; it is the essential mechanism that maintains a strict one-way flow of blood, ensuring that oxygen and nutrients are efficiently delivered to every part of the human body.

Source:
Hall, J. E., & Hall, M. E. (2020). Guyton and Hall Textbook of Medical Physiology. Elsevier.”

Mahesan Subramaniam: Fun Fact About the Sound of Your Heartbeat