Does your brain filter out the sound of your own heartbeat?

Question

Accepted Answer

The Mechanism of Sensory Gating

Yes, the brain performs an incredible process known as sensory gating to actively filter out the constant sound of the heart. This survival mechanism allows human consciousness to focus on external stimuli rather than being overwhelmed by internal physiological noise.

Why This Happens

Efficiency: The brain prioritizes novelty over constant, predictable signals.
   Focus: By suppressing the heartbeat, it frees up cognitive bandwidth for complex environmental processing.
   Predictability: Because the heartbeat is a rhythmic, constant signal, the brain classifies it as background noise or 'non-event' stimuli.

Can Humans Ever Hear It?

While the brain usually mutes this sound, it becomes audible during intense physical exertion, extreme quiet, or specific medical conditions. When the brain fails to dampen these sounds, it can lead to pulsatile tinnitus, a fascinating phenomenon where the rhythm of the heart becomes a persistent, audible beat in the ears. Ultimately, this silent rhythm remains a testament to the complex, automated brilliance of human neurology.