5. Sleep Paralysis

Have you ever been frozen stiff, unable to move or talk when falling asleep or waking up? If so, you have experienced sleep paralysis. The condition affects anywhere from 5 to 40 percent of Americans and occurs most often in teenagers. The condition isn’t dangerous – you can still breathe normally – but it can be triggered by a lack of sleep, changing sleep patterns or stress. It strikes most often when sleeping on the back. Being touched or spoken to usually ends the matter, as does making an intense effort to move. Source: American Academy of Sleep Medicine.
6. Exploding Head Syndrome

Sounds like science fiction, but exploding head syndrome really exists – and it’s most unpleasant. Sufferers imagine hearing a loud noise just before falling asleep – as if a bomb has gone off inside the head. Some people think they are having a stroke. Exploding head syndrome is most common in older people, though it has been reported in children under age 10. Source: American Academy of Sleep Medicine.