Have you ever woken up with a sudden jolt just as you’re falling asleep? Maybe it felt like one arm or leg suddenly had a strong spasm or twitch?
Perhaps you’ve woken suddenly with the sensation of falling, bouncing or even an unpleasant shock sensation that left you feeling surprised or anxious.
It may have even been your partner experiencing it, and their own jolting movement startled you back to consciousness. If this sounds familiar, it could be that that you’ve experienced hypnic jerks.
A common occurrence
You’re certainly not alone in experiencing this strange nighttime sensation; it’s estimated that 60% to 70% of people experience hypnic jerks at some point in their lives, including me!
This article will help you understand what hypnic jerks are a little better, and hopefully help put your mind at ease if you’re worried about them. You’ll also find lots of advice for dealing with hypnic jerks, both from professionals and previous readers.
The terminology in the world of sleep can be confusing at time. So it’s worth bearing in mind that hypnic jerks are sometimes referred to by different names:
- Sleep starts.
- Night starts.
- Hypnagogic jerk – hypnagogic being a term used to describe the period of time when falling asleep.
- Myoclonus, or myoclonic jerk – this is the medical term to describe an involuntary muscle twitch.
What are hypnic jerks exactly?
The latest International Classification of Sleep Disorders manual describes hypnic jerks as follows:
Sleep starts, also known as hypnic jerks, are sudden, brief, simultaneous contractions of the body or one or more body segments occurring at sleep onset. Sleep starts (or hypnic jerks) usually consist of a single contraction that often affects the body asymmetrically. The jerks may be either spontaneous or induced by stimuli.
So hypnic jerks are the involuntary twitching of one or more muscles. They usually occur just as you’re falling asleep, during what’s known scientifically as the hypnagogic state of consciousness.
They usually occur asymmetrically, which is why it often feels like just one arm suddenly jolts. And they can occur independently or in response to an external stimuli in the bedroom, such as your partner moving or making noise.
Interestingly, the muscle twitching you experience also occurs in other situations, for example with hiccups.
Some people will only experience the physical muscle twitching; others might have a sensory component, which can be quite distressing:
- The feeling of falling.
- The sensation of pain or tingling.
- An unusual noise, such as a large bang or crackling.
- Flashing or unusual lights.
That strange time of the night
It’s during the phase of falling asleep that several unusual phenomenon may take place. For example, I discussed in a previous article the various sleep paralysis experiences people have. Those can be accompanied by bizarre or frightening hallucinations and even out-of-body experiences.
Even though hypnic jerks and those other strange sleep experiences aren’t dangerous, they can be disruptive to your sleep and quite unsettling.
So even though they aren’t technically anything to worry about, they can sometimes cause anxiety and insomnia if you worry about them and/or become afraid to go to sleep.
Hypnic jerks survey results
In 2016 I conducted a short survey for readers to share their experience of hypnic jerks. With thousands of people participating, the results provide an interesting insight into how hypnic jerks affect people.
In the graph below you can see how often people experience hypnic jerks. It’s interesting to note that many of the people who searched for this article experience them on a daily basis.
An interesting point arising from poll 2 is that many people find hypnic jerks affect their sleep quite badly. However, there are also many who only have some initial disruption, or none at all.
It appears clear in poll 3 that many people feel stress or anxiety makes their hypnic jerks worse.
This is a factor which appears many times in the hundreds of comments readers have left below. So it could be that tackling stress or anxiety is a good idea if you’re struggling with hypnic jerks.
What causes hypnic jerks?
So now you know that hypnic jerks are twitching of the muscles. But what causes the muscles to twitch in the first place?
As is often the case in the complex world of sleep, scientists still aren’t completely sure of the cause. However, they do believe that the following factors can all contribute to hypnic jerks happening:
- Caffeine or other stimulants
- Anxiety or stress
- Heavy physical exercise or work
- Sleeping in an uncomfortable position
- Being very tired or sleep deprived
In addition to these factors which can contribute to the likelihood of a hypnic jerk occurring, there are some theories as to why they happen:
1. The first theory is that they happen as your nervous system relaxes and slows down when transitioning from wakefulness to sleep. Your breathing slows down, temperature drops and your muscles relax. So hypnic jerks might happen when nerves misfire during this slowing down process, resulting in the muscular spasm.
Or as the International Classfication of Sleep Disorders states:
Hypnic jerks are hypothetically caused by sudden descending volleys originating in the brainstem reticular formation activated by the system instability at the transition between wake and sleep. However, the similarity between sleep starts and the startle response has led some to postulate that abnormalities of sensory processing are primary, with secondary motor manifestations involving the reticulospinal tract.
2. A second theory postulated by some is that hypnic jerks occur in response to the common occurrence of sleep hallucinations or the onset of dream imagery. Perhaps this explains why people sometimes feel like they are falling.
3. An evolutionary theory suggest that your brain wakes you up one last time, so you can check that you’ve take the necessary steps to keep yourself safe at night.
Is it another sleep disorder?
A 2015 review into hypnic jerks by researchers at the University of Alabama raised an important point – hypnic jerks could in some cases be a characteristic of another illness.
So although they are benign for most people, if you have them regularly and/or severely, you might want to raise it with your primary care doctor to be sure it’s not a sign of another condition. Some of the possibilities they suggest in the review are:
- Noctural seizures
- Nonepileptic seizures
- Other parasomnias
- Restless legs syndrome (RLS)
- Periodic limb movements in sleep (PLMS)
- Excessive fragmentary myoclonus
- Psychiatric diagnosis
How can you stop hypnic jerks?
The hypnic jerk is such a common occurrence that it may not be possible to prevent it happening completely. However, you can take steps to address some of the factors thought to increase the likelihood:
- Cut down on alcohol and caffeine, especially in the 3 to 4 hours before going to bed.
- Reduce how much heavy exercise or work you do in the evening.
- Ensure you’re getting sufficient magnesium and calcium in your diet – this can help with muscle and nerve spasms.
- Make sure you have a comfortable mattress and bedding, and that you sleep in a comfortable position.
- If you suffer from anxiety or stress, you can try doing some simple relaxation exercises and mindfulness exercises.
- Try not to allow yourself to get too tired or fatigued. You may understandably have a very busy and tiring lifestyle. But it’s important to give yourself enough time to sleep well.
Avoid the vicious cycle of worry
Hypnic jerks can trigger a vicious cycle of worry if you become fixated on them. This is a common thing that happens with many sleeping difficulties.
For example, people who have insomnia for a few nights might start worrying that they won’t be able to get to sleep. This worrying then becomes the thing that causes their insomnia, even if the original cause has long gone.
If you worry about hypnic jerks unnecessarily, you might start to get less sleep and become more fatigued. But both anxiety and fatigue are thought to contribute to the frequency of hypnic jerks, so the vicious cycle begins.
You now know that occasional hypnic jerks are very common, so hopefully you can relax about them. I know the earlier list of other possible illnesses might be a cause for concern now. If it is, talk to your doctor about it to get some reassurance and peace of mind.
But for the majority of people, the key is not to allow the occasional hypnic jerk to disrupt your sleep any more than it has to. Try to relax, forget about it and go back to sleep.
Readers’ tips and techniques to stop hypnic jerks
In the comments below, many previous readers have offered their own ideas on what can make hypnic jerks better or worse.
First of all, I’d like to acknowledge and thank everyone for such detailed comments and for sharing your thoughts.
Secondly, I’m going to start a list of ideas which people have provided. Please note that many of these have no scientific evidence to back them up. It’s simply a list of anecdotal ideas that may or may not help.
- Try to see the funny side. Many readers have said that they just laugh them off.
- Magnesium supplements have been helpful for many readers, as has rubbing magnesium oils or transdermal magnesium into the area where you most commonly twitch. One suggestion was to get a blood test to check if you have a deficiency. A reader reported that after several months of taking 2 x 500 mg magnesium citrate supplements every day, the hypnic jerks reduced significantly.
- Continuing with the theme of hypnic jerks being made worse by a mineral deficiency, it’s important to assess your current diet. Try to have a healthy, balanced diet. Eat less sugary and salty foods, and eat plenty of fresh fruit and vegetables.
- Don’t drink alcohol, coffee or energy drinks for a week and see if it improves.
- Don’t stress about it, as worrying makes it worse.
- Try to deal with major stress in your life – many people say hypnic jerks are much worse when they feel stressed.
- If you suffer from anxiety, take steps to tackle this in your daily life.
- Drink cayenne pepper tea (I suggest doing some research into this first).
- Try acupuncture.
- Make sure you get enough calcium in your normal diet, or take supplements.
- Stop working out for a while if you’re doing strenuous exercise and see if it improves.
- Try to see them as a sign that you must be falling asleep, and that it’s a positive thing as you know you’ll soon be asleep.
- Talk to your doctor about any medication you’re taking, including over the counter sleep aids to check if any could be increasing the frequency or strength of your hypnic jerks.
- In addition to the above, check that medication you’re taking doesn’t have a side-effect of myoclonus – a surprising amount do.
- Sleep aids and allergy medication containing the anti-histamine diphenhydramine can sometimes cause twitching. Try stopping them temporarily if you use them regularly.
- Try taking electrolyte pills or solutions which athletes use and are also given for fluid loss.
- Try to sleep in a different position from your back – one suggestion was that the fetal position can help.
- Don’t go to bed late at night.
- In terms of prescription medication, some people say clonazepam has helped them (benzodiazepines are not a long-term solution though).
- Film yourself sleeping or use a sleep monitor. One reader said he discovered through doing this that he was snoring, and that the hypnic jerks occurred while he was snoring heavily.
- Some female readers feel that it can be connected to hormonal changes.
- Ask for a referral to a sleep clinic if you’re able to and it’s particularly troubling.
- Ensure you have a quiet sleeping environment – it could be a sudden noise which startles you awake.
- Stay hydrated by drinking plenty of water during the day.
- If you’re being bothered by them repeatedly, get up and do something relaxing for 10-20 minutes, then try to sleep again.
- Have a light snack before bed. And if they’re occurring repeatedly, get up and have a light snack.
- Have a warm shower before bed, then do relaxation exercises before getting into bed or even while in bed.
- If you do exercise, it could be excess lactic acid contributing to hypnic jerks. So try looking into ways to reduce the lactic acid, and don’t do heavy exercise in the 3 to 4 hours before bed.
- Try apple cider vinegar. It’s used as a hiccup remedy, so might help with hypnic jerks too.
(please read before leaving a comment)
After nearly 4 years of replying to comments, I’ve decided to hand the discussion over to you, the reader. I’ll still personally read them all, and reply if necessary, but I won’t be able to reply in depth due to time constraints.
It’s always very interesting to hear your experiences, and I know many readers have benefited from reading the stories and advice of others.
So please keep your comments, tips and theories coming. And if you have any practical ideas for dealing with hypnic jerks, I’ll continue to add them to the list of readers’ suggestions.