An episode of Keeping Up with the Kardashians saw model Kendall Jenner reveal her fear of going to sleep because of a condition called sleep paralysis. “I wake up in the middle of the night and I can’t move,” she said in the reality TV show.
It can be frightening. “Sleep paralysis renders a person unable to speak or move just as they are about to fall asleep, or while they are transitioning to the wakeful state,” says Dr Cheryl Kam, a family physician at Mint Medical Centre, who has an interest in sleep disorders.
But sleep paralysis is actually a fairly common sleep disorder, affecting four in 10 people. There are others with less obvious symptoms, which make them harder to spot.