It is actually NOT a fact. The idea that we eat or swallow spiders while we sleep is actually an urban myth.
This myth seems to have come from a PC Professional article published in 1993 in which columnist Lisa Holst made up fake “facts” to demonstrate how gullible people can be. Ironically, her article seems to have helped spread one of the most widely believed misinformation found on the internet.
In actual fact we probably don't eat any spiders at all while we sleep. Spiders have no interest in going into our mouths and probably sense danger from vibrations caused by a sleeping person’s breath, heartbeat and snoring and will do all they can to avoid us.
The chances of a spider falling into your mouth AND you not spitting it out AND it not trying to get away AND you swallowing it are minute.
