Your body puts the sneeze reflex on pause while you sleep—especially during REM sleep, when you're temporarily paralyzed to keep you from acting out dreams.

That pause also affects your trigeminal nerve, which detects nasal irritants. Its sensitivity drops, making it less likely to trigger a sneeze.

On top of that, the brain areas that control sneezing are less active during sleep. You might sneeze right after waking, but while you're asleep, your body hits the snooze button on sneezing.