There you are, lying down at last. Fresh sheets, soft pillow, your body slowly gives way, your thoughts become more blurred... when suddenly, a strange sensation of freefall tears you from your ...

Have you ever jumped just as you were about to fall asleep, with the sudden sensation of falling into a void? This phenomenon, although surprising, is actually very common and has a name: hypnic jerk.

Sign up for CNN’s Sleep, But Better newsletter series. Our seven-part guide has helpful hints to achieve better sleep. When Dr. Luc Beaudoin was an undergraduate ...