Uninterrupted Sleep

What is a hypnic jerk?

What does it mean when you twitch in your sleep? If you’ve ever experienced a significant twitch or sudden movement just before falling to sleep, you may have been having a hypnic jerk. Hypnic jerks is an involuntary muscle twitches or sudden movement as you’re falling asleep. Hypnic jerk can be called by other names as well. They can be called by any one of these names:

  • Sleep starts
  • Hypnagogic jerk (the term “hypnagogic” refers to a jerk that happens right before falling asleep or when in the process of falling asleep)
  • Night starts
  • Myoclonic Jerk (which can describe any type of involuntary muscle movement that can occur while awake or asleep at any time)

Hypnagogic jerk

Hypnagogic refers to a jerk that happens right before falling asleep or when in the process of falling asleep. In other words, it’s the time when you’re not fully awake, but are not quite asleep too.

Hypnic Jerk symptoms

This is what happens when you experience a hypnic jerk. You are usually lying down although it can occur when you have fallen asleep in a chair. Just before or as you are beginning to fall asleep, you experience a jolt that is similar to the experience of being startled by a noise or other interference. It often goes along with the sensation of falling and you might also notice the following symptoms:

  • Jerking of the extremities or of the whole body

  • Feeling as though you are falling down into a void

  • Rapid heart rate

  • Faster breathing

  • Sweating

It is believed to be an involuntary reflex that was evolutionarily built into our bodies when our primate ancestors slept in trees and needed to awaken themselves suddenly in order to avoid falling out of the tree. Now, of course, this is not the case and the reflex has very little use in modern man. It can occur in anyone at any age but is more common in people who do not keep a regular sleep/wake cycle.

What causes hypnic jerks?

In the majority of cases, no one knows exactly what causes hypnic jerks. It occurs in healthy people with no risk factors and occurs at random times in their lifetime. People are more likely to experience this phenomenon after strenuous activity, increased psychosocial stress, caffeine intake and anxiety.

Myoclonic Epilepsy

Hypnic jerks can look a lot like myoclonic epilepsy, in which the brain sends an epileptic spike that jerks the muscles. However, in hypnic jerks, there is no brain wave spike precipitating the jerking motion. It occurs only at the onset of sleep, which is another thing that differentiates it from myoclonic epilepsy.

Hypnic jerks occur during which stage of sleep?

Hypnic jerks occur during non-REM (non-rapid eye movement sleep). In it, the muscles are flexed and the jerk can be on one side of the body (unilateral) or both sides of the body (bilateral). Children are more likely to experience hypnic jerks, peaking particularly around the age of 8-12 years of age, who can have up to 7 hypnic jerks in a single hour. The incidence of hypnic jerks lessens with aging, so that people aged 65-80 tend to have fewer than 1-2 hypnic jerks per hour at the time of sleep initiation.

Having hypnic jerks sets up a nasty cycle that further interferes with sleep.   For example, you can have a high frequency of hypnic jerks that cause you anxiety and fear over falling asleep. This leads to further sleep deprivation and anxiety so that you cycle back toward having more hypnic jerks, etc. The more times you are jerked away from sleep, the more sleep you lose and the more prone you are to having more hypnic jerks. The cycle can only be broken by getting plenty of quality sleep and sleeping more regular hours.

How common are hypnic jerks?

Hypnic jerks are very common, affecting about 70 percent of the population at some point during their lives. As mentioned, they can occur at any age, with some people having these jerks nearly anytime they fall asleep.

An unofficial internet-based poll indicated that about 41 percent of all people had some type of hypnic jerk at least twice a week, while 38 percent of people stated they had these types of jerks nearly every day. Only 21 percent of people experienced hypnic jerks rarely, and nobody said they had never had this phenomenon happen to them.

What does a hypnic jerk feel like?

A hypnic jerk feels as though you are falling down into a void. Hypnic jerk is a myoclonic muscle spasm that occurs during the time of nearly falling asleep. It is the same jerking sensations you feel when someone has startled you and, if it happens while you are trying to fall asleep, you get the sense that you are falling out of bed or into a void. Like sleep paralysis, these jerks happen right before falling asleep—a time when your body is drifting into the sleep state from a state of wakefulness.

Is hypnic jerk dangerous?

Fortunately, hypnic jerks are not at all dangerous but they can be quite annoying if you get them often enough to interfere with sleep. When you are under stress is one of the times when these jerks are likely to happen, as psychosocial stress can be activating to the body’s nervous system. Unlike a seizure disorder, hypnic jerks do not mean you are prone to getting epilepsy with all of its complications. On the other hand, hypnic jerks can come and go and do not gradually get worse unless you become severely sleep deprived.

Hypnic jerks fall under the category of muscle twitches and do not appear to come directly from the brain like epilepsy. They are more similar to the muscle twitches seen in hiccups, which are muscle twitches of the diaphragm.

Hypnic jerk cure

There is no specific cure for hypnic jerks other than to have good sleep habits, getting at least 7-9 hours of sleep per night and falling asleep around the same time every night. If you are prone to hypnic jerks, you can lessen their frequency by avoiding alcohol, smoking, and stimulants like caffeine just before going to sleep. Exercise is good for hypnic jerks as long as you exercise at least 4-5 hours before trying to fall asleep.