Sneezes Don't Happen Asleep

Humans can't sneeze in their sleep because REM sleep switches off the body's motor responses. During this sleep stage, the brain dampens sensory input and blocks the reflex pathway, so normal nasal irritation never triggers a sneeze. A strong enough stimulus will wake you up, and only then will the sneeze start. The reflex stays offline until the brain lifts that REM paralysis.

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