Why Do We Suddenly Jerk Awake?

Many individuals suffer from the same anomaly—just as they are dozing off at night, they get the sudden sensation they are falling, and a second later, their bodies will jerk, bringing them back awake.  For some, the feeling creates such anxiety that they have difficulty falling back to sleep.

According to sleep experts, this sensation is common and is not anything to worry about.  The feeling of falling and then being jerked awake is what is called a hypnic jerk.

Although the experience can be a somewhat alarming one, as it turns out is a normal occurrence and is not to be seen as any sign of an underlying problem.

As many as 60-70% of people have reported that they have experienced these hypnic jerks on occasion, according to a recent report in the International Classification of Sleep Disorders—which is a manual that is sourced for diagnosing sleep-related issues.

The hypnic jerk also referred to as sleep start, is an involuntary movement of our bodies, usually within a large muscle group.  The jerk usually happens when we are in the transition phase from being awake to falling asleep.

Image: University Health News

During this jerk, some have been known to swing their arms or to kick their legs.  If you are resting in an upright position, you may also be prone to snapping your head backward.

Because hypnic jerks are considered normal and benign, there hasn’t been much research done on them—and as a result, to this day are not very well understood.  Research has shown that the jerks are more likely to happen in those individuals who have been sleep-deprived.

When an individual is in this state, research has found that some regions of their nervous system are asleep, while at the same time, other areas remain awake. Because your nervous system has different means of control over the movement so your muscles when you are asleep rather than when you are awake, your limbs will tend to flail and twitch.