What even are those pre-sleep body jerks—and can you shake them for good?

Have you ever experienced that completely terrifying moment when you’re falling asleep and suddenly twitch yourself to a startling state of alertness? Well, while the experience might be disruptive (and alarming!), the sudden body jerks are actually super normal—and there are a few different reasons why they may happen.

According to Time, the phenomenon—called hypnic jerks—happens to 60 to 70 percent of Americans, whether they actually wake you or not. But despite the involuntary movement being so common, there’s no precise explanation; rather, sleep behavior expert James Wilson has some compelling hypotheses.

It turns out being sleep-deprived, anxious, drinking caffeine, or exercising near your bedtime makes you more likely to experience jerks, which occur when one part of the brain tries to doze off faster than the others.

“The complexity of going to sleep and waking up is incredible, and sometimes—particularly when we are sleep deprived—our brain doesn’t shut down normally, which means we get this sort of jerking movement when we’re in a light sleep.” —James Wilson, sleep expert

“The complexity of going to sleep and waking up is incredible, and sometimes—particularly when we are sleep deprived—our brain doesn’t shut down normally, which means we get this sort of jerking movement when we’re in a light sleep,” Wilson said. And when the brain tries to figure out what’s happening, that’s when “we imagine ourselves falling off the sidewalk, a cliff, or in a hole.”

The whole falling-off-a-cliff thing isn’t a pleasant way to go to sleep, but, phew, there are some things you can do to prevent pre-sleep body jerks from happening. And according to Wilson, they start with the foundation of a proper bedtime.

“Wake up at the same time every day, and wind down properly before going to bed, making sure the activities you do in the hour before going to sleep are relaxing to you,” Wilson said. “Like most issues surrounding sleep, preventing hypnic jerks is all about trying to solve that sleep deprivation.”

So grab your sleep-inducing essential oils, turn off your phone, and wind down in the most peaceful way possible. Doing so will increase your odds of waking up after a good night’s rest to your pleasant chime alarm—rather than minutes later, while you’re mentally free-falling off Mount Everest.

Stay away from these foods before bed for better sleep. Also, here’s an expert-approved way to finally get some sleep on a plane.