Have you ever woken abruptly with a jerk or falling sensation? There’s a name for that: hypnic jerks.
Hypnic jerks can be unpleasant and even a bit alarming. If you’re ever concerned about the severity or frequency of hypnic jerks, don’t hesitate to discuss it with your doctor.
But the good news is that they’re usually a harmless, normal part of falling asleep. Only in rare cases do hypnic jerks lead to bigger issues such as injury or insomnia.
We talked to a sleep physician to find out everything you need to know about hypnic jerks, including what causes them and how to prevent them.
What is a hypnic jerk?
“Hypnic jerks, also known as sleep starts, are brief muscle contractions that occur at sleep onset,” says Stephanie Stahl, MD, sleep medicine physician at Indiana University Health.
For up to 70% of people, hypnic jerks are a part of everyday life. These involuntary muscle contractions can happen to adults of all ages and health levels.
What does a hypnic jerk feel like?
Hypnic jerks vary in severity and frequency. You might feel a fast jerking motion, a series of involuntary twitches, or even a stomach-churching falling sensation.
Sometimes your hypnic jerks wake you up-and sometimes they wake your bed partner instead. Because some hypnic jerks are only minor twitches, you might not rouse enough to know you’re experiencing them.
Hypnic jerks can also be multisensory. Stahl says some people think they heard a loud bang or saw flashing lights. “Some people may have multiple jerks or even cry out,” she adds.
What causes hypnic jerks?
It’s difficult to pinpoint the exact cause of hypnic jerks. Experts are still uncertain how to explain or predict them. Stahl says disruptions to your sleep-to-wake transition might contribute.
Here are some potential causes of hypnic jerks:
Are hypnic jerks dangerous?
Hypnic jerks alone aren’t considered dangerous. However, a hypnic jerk can make you accidentally kick your bed partner or stub your toe on the footboard. Frequent hypnic jerks might also trigger stress or anxiety about falling asleep, leading to restlessness and insomnia.
True hypnic jerks occur only during the transition between waking and sleeping. Consult a medical professional if you start experiencing sudden involuntary muscle contractions (myoclonus) during the day. Myoclonus can sometimes indicate an underlying neurological condition or adverse reaction to a medication.
How to stop hypnic jerks
Because hypnic jerks aren’t dangerous, there’s no medical reason to try to prevent them. And because the cause of hypnic jerks is still unknown, there’s no surefire prevention method.
That said, maintaining a consistent sleep schedule might reduce the frequency of these sleep starts, says Stahl. Here are some other tips to help prevent startling yourself awake while falling asleep:
FAQs
What are the symptoms of hypnic jerks?
The symptoms of hypnic jerks include involuntary muscle twitches or clenching. Some hypnic jerks are also accompanied by a falling sensation, visualization of flashing lights, or auditory hallucination similar to a loud bang.
Is a hypnic jerk a disorder?
Hypnic jerks alone don’t indicate a medical disorder. They aren’t considered dangerous or alarming. In fact, about 70% of adults experience sleep starts.
Is a hypnic jerk anxiety?
Hypnic jerks might be exacerbated by anxiety, but experiencing a hypnic jerk doesn’t necessarily mean you have anxiety. “Anxiety and stress are potential causes of hypnic jerks,” explains Stahl.
Sleep talking is another phenomenon that’s fairly common. Learn more about what causes sleep talking and how to stop doing it.
