Experts explain 'distressing' exploding head syndrome as millions experience it before falling asleep

'Exploding head syndrome' is on the rise - 6 signs of the terrifying condition

A hypnic jerk (also called a sleep start) is a sudden, involuntary muscle twitch or jolt that happens just as you are about to fall asleep. Here’s what you need to know: When it happens: Usually during the transition from wakefulness to light sleep. What it feels like: A quick jerk of the arms, legs, or whole body, sometimes accompanied by the sensation of falling, a dream-like flash, or even a gasp. Why it happens: The nervous system misfires as the brain shifts from wakefulness to sleep. Stres

What is exploding head syndrome? - Stuff You Should Know