Snoring happens when air has to move through a narrowed upper airway during sleep.
That moving air can make soft tissues vibrate.
The vibration creates sound.
Sleep relaxes the airway
When you fall asleep, muscles throughout the body relax.
That includes muscles in the tongue, soft palate, and throat.
For some people, the relaxed tissues narrow the passage enough that airflow becomes turbulent.
Now the tissue can flutter.
Why is snoring louder in some positions?
Sleeping on your back can allow the tongue and soft tissues to fall backward more easily.
That can narrow the airway further.
For some people, side sleeping reduces snoring.
Why does congestion make it worse?
A stuffy nose increases resistance to airflow.
You may breathe more through the mouth.
The entire upper airway can become noisier.
That is one reason nasal congestion can turn a quiet sleeper into a temporary chainsaw.
Does everyone snore?
No.
Some people rarely snore.
Others snore frequently because of anatomy, weight, nasal obstruction, alcohol, sleep position, or other factors.
Age can also affect airway muscle tone.
Is snoring always harmless?
No.
Occasional snoring can be harmless.
Loud frequent snoring combined with pauses in breathing, choking, gasping, or severe daytime sleepiness can be a sign of obstructive sleep apnea.
That deserves medical evaluation.
Is snoring the same as sleep talking?
No.
Sleep talking involves speech-related brain activity during sleep.
Snoring is a mechanical airflow sound.
One comes from the airway vibrating.
The other comes from the sleeping brain producing speech.
So snoring is basically airflow turning relaxed throat tissue into an unwanted nighttime instrument.
And that’s the short explanation.
Related explanations: Why do we talk in our sleep?, Why does your nose get stuffy?, and Why do we sleep?