We drool when we sleep mainly because during sleep, especially in deep stages, the muscles around the mouth and face relax, causing the mouth to sometimes fall open. This allows saliva, which we continuously produce, to escape instead of being swallowed. Additionally, our sleeping position plays a significant role: lying on the side or stomach lets gravity pull saliva out of the mouth more easily than lying on the back. Other factors that can increase drooling include nasal congestion (which forces mouth breathing), certain digestive issues like GERD that increase saliva production, and some neurological or health conditions affecting swallowing reflexes.
Here's a brief overview of the main causes:
- Relaxed facial and jaw muscles during deep sleep cause the mouth to open, letting saliva escape.
- Sleeping on the side or stomach pulls saliva out due to gravity.
- Nasal congestion from colds, allergies, or infections promotes mouth breathing, increasing drooling.
- Conditions like GERD can lead to excess saliva production.
- Neurological or dental issues may impair swallowing, causing more drool.
In most cases, drooling during sleep is normal and harmless, but excessive drooling or new onset drooling might warrant medical attention if linked to other symptoms.
