Why We Drool in Our Sleep: What Your Brain Is Really Doing When You Rest

The scientific term for nighttime drooling is nocturnal sialorrhea. It occurs when the amount of saliva in your mouth exceeds what you can comfortably hold or swallow.

During the day, you swallow frequently—sometimes hundreds of times per hour—without even realizing it. Your brain constantly monitors saliva production and muscle activity in your mouth to keep everything balanced.

At night, that balance changes. As your body relaxes into sleep, your muscles loosen, including those around the mouth and face. That relaxation makes it easier for saliva to escape, especially if you sleep on your side or stomach, allowing gravity to do its work.

If you’ve ever woken up to find your pillow a little wet, it’s likely because your brain has temporarily “paused” its control over your swallowing reflex while still keeping the rest of your body functioning smoothly.

What the Brain Is Doing While You Sleep

Continue reading…