Drifting off to dreamland isn’t always smooth sailing. Maybe you’ve had this experience: Just as you’re drifting off to sleep, you suddenly feel like you’re falling off a cliff. Your muscles clench, jerking you back awake.
It’s far from a relaxing feeling, but it’s nothing to be worried about — or lose sleep over. Those muscle spasms are called hypnic jerks, and they’re a natural phenomenon.
“They occur when your muscles contract involuntarily on the cusp between wakefulness and falling asleep,” says Dr. Ingemaud Gerber, medical director for Evolve Retreats. “They are caused by sudden muscle contractions or muscle relaxation.”
Here are a few answers to frequent questions about this strange feeling some of us experience as we’re falling asleep.
Are Hypnic Jerks Normal?
Hypnic jerks are common. Most people — as many as 70 percent — have felt them at some point. “It involves a total body experience where your muscle contracts therefore your limbs jerk or your body twitches,” James K. Walsh, executive director and senior scientist at St. Luke’s Sleep Medicine and Research Center in St. Louis, told NBC.
What Causes Hypnic Jerks?
Scientists still don’t quite know what causes them, psychologist Tom Stafford reported for the BBC. And though we’re usually paralyzed while we sleep, “Hypnic jerks seem to be a sign that the motor system can still exert some control over the body as sleep paralysis begins to take over,” he wrote.
Can You Prevent Hypnic Jerks?
Sleep deprivation, as well as poor sleep habits, will make you more susceptible to hypnic jerks. “While the physiology of these involuntary movements remains unknown, we do know that you’re more likely to experience hypnic jerks if you have poor sleeping patterns or have been sleep deprived,” Dr. Andrew Weil shared on his website.
Meditation or other relaxation techniques and avoiding caffeine before bedtime can help you avoid experiencing hypnic jerks. “Anxious thoughts or stress may keep your brain active even as your muscles try to relax as you drift off to sleep,” Gerber said.
So, as long as you follow better sleep hygiene, you’ll be able to calmly drift into dreamland every night.