This Is Why Your Body Jerks Right After You Sleep

One moment we’re drifting away to deep unconsciousness in sleep, and another our body being jolted back into reality! Has this ever happened to you? Turns out this jerks happened to most of us; for some people, it occurs on an all-too-frequent basis. If you’re like most, you’ve probably wondered why this happens. Indeed, it is a strange spectacle.

This phenomenon is called a hypnagogic jerk. The name is derived from the hypnagogic state – the transitional period between wakefulness and sleep. Hypnagogic jerks are often simply referred to as hypnic jerks.

Hypnic jerks generally involve sudden, erratic movement (i.e., twitches or spasms) of the arms, legs or the entire body. Most often, hypnic jerks occur while trying to drift off to sleep. Interestingly, many people experience the sensation of falling immediately prior to sudden muscle twitches and abrupt awakening.

Researchers are not entirely certain as to the physiological rationale of hypnic jerks, although there are plenty of accepted theories. Most scientists and physicians believe that these jerks simply result from the brain transitioning to a lower frequency. Our brains produce high levels of activity from the moment we awake to the time we begin to “unwind” in the evening; hence, it seems plausible that the brain will, at times, attempt to regain this natural state of activity.

Another common theory is how the brain responds to an exhausted body. More specifically, when we’re extremely fatigued, the brain will sometimes transition to the first stage of sleep too quickly instead of following a slower and more natural progression. Normally, in the first stage of sleep, respiratory activity and heart rate slow down; the body “stills,” and our state of sleep is quite light. According to the defense mechanism theory, when our bodies reach this state too quickly due to exhaustion, the brain may interpret it as a threat and initiate a jerking response.

Can Hypnic Jerks Be Avoided?

The simple answer: yes and no. Apologies, as that isn’t really a simple answer. Here’s some elaboration. The human brain is a remarkably complex organ, producing stimuli that are sometimes unexpected (thus unexplainable). As is common knowledge, the brain normally operates at frequencies within certain ranges depending upon the activity at hand. These predictable range frequencies allow us to maintain a normal sleep cycle.

Sometimes, though, the brain involuntarily produces signals that are beyond normal, expected ranges of frequency. We experience these anomalies in a number of ways (e.g. daydreaming, losing track of time), including in our sleep cycles. Jet lag is another common sleep disruptor caused by involuntary, erratic brain activity.

That said, there are a few things scientists do know. First, sleep deprivation is a trigger of hypnic jerking. Not getting the recommended amount of sleep (7-9 hours) on a frequent basis can lead to hypnic jerking. Pulling an all-nighter for work or studying is counterproductive and can result in jerking awake. Excessive consumption of alcohol or nicotine, especially before bedtime, can have us twitching ourselves awake.

The Answer: Good Sleep Habits

Granted, this is a humdrum and bland answer…but it’s very true. Practicing good sleep habits: going to bed and waking at the same time; abstaining from alcohol and nicotine; getting 7-9 hours regularly; putting the phone away; tackling difficult tasks early; limiting the amount of light during sleep time; etc. will help limit those jerking episodes. More importantly, we’ll be our most productive selves.

In summation, hypnic jerks are frightening, but they’re not dangerous. They’re not even a sleep disorder. The preeminent organization of sleeping behaviors – the National Sleep Foundation (NSF) – estimates that nearly 70 percent of people experience hypnic jerks at some point.

Now, should these twitching episodes become a regular occurrence, it may be indicative of a disorder such as chronic insomnia. Of course, a doctor’s appointment would be wise in such cases. However, a sleep disorder originating from hypnic jerks is very rare.

As NSF says: “There are no serious consequences, it won’t give you a heart attack or anything – the worst that can happen is you jerk so hard that you fall out of bed.”

So, if you should tumble from your delightful resting place, just jump back under the covers and shut those eyes. You needn’t worry your little sleeping head about it.

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