Snoring is common during sleep, often disturbing others more than the snorer. We rarely hear our own snoring, despite its audibility to those around us. This phenomenon involves the physical origins of snoring, how humans perceive sound, and the brain’s auditory processes during sleep.
The Mechanics of Snoring
Snoring occurs when airflow through the mouth and nose is obstructed during sleep. As a person sleeps, muscles in the throat, tongue, and soft palate relax. This relaxation narrows the airway. When air passes through this constricted space, it creates turbulence that vibrates these relaxed tissues, generating the characteristic snoring sound.
The sound quality, whether soft or loud, varies depending on which throat parts vibrate, such as the soft palate, uvula, or tongue base. Snoring is a low-frequency sound, often below 500 Hz, with the soft palate’s flutter contributing to its harshness.
Internal Versus External Sound Perception
Humans perceive sound through two main pathways: air conduction and bone conduction. Air conduction is how we hear external sounds. Sound waves travel through the air, enter the ear canal, vibrate the eardrum, and transmit through the middle ear bones to the inner ear, where they convert into electrical signals for the brain. This is how a bed partner hears someone else’s snoring.
Bone conduction involves vibrations traveling directly through the skull bones to the inner ear, bypassing the outer and middle ear. When we speak, we hear our own voice largely through bone conduction, which is why our recorded voice often sounds different. Similarly, vibrations from our own snoring transmit through our skull bones to our inner ear. This internal perception makes the sound seem less loud or different, making it difficult to consciously register.
The Brain’s Auditory Filtering
During sleep, the brain actively filters sensory information, a process known as auditory gating or selective hearing. This mechanism allows the brain to prioritize certain sounds while suppressing others, enabling uninterrupted rest. Constant, familiar, or non-threatening sounds, such as one’s own breathing or internal bodily noises, are filtered out or muted by the auditory cortex. This explains why one’s own snoring is largely ignored.
The brain’s ability to filter sounds supports sleep quality, ensuring important external stimuli, like an alarm or a child’s cry, can still register while irrelevant noises are suppressed. While the primary auditory cortex remains somewhat responsive during sleep, higher brain regions show subdued responses, contributing to a lack of conscious awareness. This filtering system, alongside different pathways of sound perception, helps explain why snorers rarely hear themselves.