A Medical Daily news report examines the phenomena of sleep paralysis, which is thought to be connected to REM sleep.
For whatever reason — researchers still don’t have a concrete explanation — we can wake up right as we enter or exit REM sleep while our bodies remain rigid and unmoving. Even though we’re not in any danger of suffocating, the fact that we can’t breathe voluntarily leaves us petrified of that possibility, and the lingering traces of REM sleep also make us susceptible to auditory and visual hallucinations.
According to UK researchers Christopher C. French and Julia Santomauro, who have written about the phenomenon as a part of a chapter in the 2007 book Tall Tales about the Mind and Brain, SP can last anywhere from seconds to minutes and it most often occurs soon after we drift into sleep or right before we’re ordinarily supposed to wake up. Unlike the night terrors of our children, SP occurs most often in adults.