Have you ever woken up with a sudden jolt just as you were falling asleep? Maybe it felt like an arm or leg had an involuntary spasm?
Perhaps you’ve even woken up feeling like you were falling, or with a flash of light or loud noise. If this sounds familiar, it could be that that you’ve experienced hypnic jerks.
In most cases, a hypnic jerk or two is a harmless part of the process of falling asleep, and doesn’t mean you have a sleep disorder. But if they regularly disturb your sleep or happen very often, it might help to speak to a medical professional.
A common occurrence
You’re not alone in experiencing this strange sensation at night. Italian researchers suggest that between 60% and 70% of people experience hypnic jerks at some point in their lives – both men and women, and of all ages.
I regularly have hypnic jerks myself – especially when I’m extremely tired or stressed. I’ve also noticed that if I train hard in the gym late in the evening, they seem to happen more often and the movements are more pronounced.
Personally, I don’t worry about them, and see them as a sign that some much needed sleep is just around the corner.
If you research online about hypnic jerks, it’s worth bearing in mind that they are sometimes referred to by different names:
- Sleep starts.
- Night starts.
- Sleep jerks.
- Hypnagogic jerk.
- Myoclonic jerks (myoclonus is an involuntary muscle twitch – hiccups are another harmless example).
What are hypnic jerks?
Hypnic jerks are the sudden involuntary twitching of one or more muscles when you’re falling asleep. The International Classification of Sleep Disorders manual describes them 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 the fact that they often occur asymmetrically explains why it might feel that just one arm or leg jolts.
They can occur independently or in response to external stimuli in the bedroom, such as your partner moving or external noise.
The most common symptom is the sudden jolting sensation of one or more limbs. However, some people might also experience the following:
- The feeling of falling.
- A sensation of pain or tingling.
- Hearing a sudden noise, such as an explosion. This could also be what’s known as exploding head syndrome.
- Flashing or unusual lights.
In addition, some people might notice a physiological response, such as faster heartbeat or breathing, and sweating.
Reader survey results
Back in 2014, I conducted a short survey for readers to share their experience of sleep starts. The results will be biased because people voting were already searching for information about the topic.
But with thousands of people participating, the results still provide some interesting insights.
In the chart below you can see how often voters experienced hypnic jerks. It’s interesting to note that many readers had them on a daily basis.
2. How they affect your sleep
Question 2 shows that many people are able to sleep well after an episode. And that’s in line with the general medical advice – try not to stress about them, and go back to sleep.
3. The role of stress and anxiety
The final question shows that many people feel stress or anxiety makes their hypnic jerks worse. This is also a factor which appears many times in the comments below.
So it could be that tackling stress or anxiety in your life is a good idea if it’s relevant to you.
What causes hypnic jerks?
As is often the case in the complex world of sleep, the exact cause still isn’t completely understood.
The International Classification of Sleep Disorders manual offers this technical explanation:
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.
Or in layman’s terms, your brain and body are briefly a little bit out of sync as you relax and go from being awake to being asleep.
I regularly check for new research into hypnic jerks, and there has been very little published in the last few years. Since it’s historically been seen as benign, it doesn’t attract much attention and research. For that reason, there isn’t a clearer explanation as to exactly why it happens.
Researchers in 2018, for example, say that “the origin and physiology of hypnic jerks remain enigmatic.”
Factors that can increase the frequency and severity of hypnic jerks
Although the exact cause is still up for debate, sleep experts do suggest factors that might increase the severity or likelihood of them happening:
- Excessive caffeine or other stimulants, such as nicotine or drugs.
- Anxiety or stress.
- Intense physical work or exercise.
- Sleep deprivation due to sleep disturbance or poor sleep habits.
Is it caused by another condition?
A review of hypnic jerks literature by researchers at the University of Alabama raised an important point: hypnic jerks could in some cases be a characteristic of another condition.
Some of the possibilities they suggest include:
- Nocturnal seizures.
- Non-epileptic seizures.
- Restless legs syndrome.
- Periodic limb movements in sleep.
- Excessive fragmentary myoclonus.
- Psychiatric diagnosis.
In addition, Italian researchers in 2016 found that hypnic jerks are common in people with Parkinsonism. The Alabama team also suggested it could be helpful in diagnosing the condition.
Finally, don’t confuse sudden wakings from hypnic jerks with sleep apnea. If you, or someone you know, wakes suddenly gasping for breath, this should be discussed with a doctor.
Treatment for hypnic jerks
Do you need to see a doctor?
Most sleep experts advise that hypnic jerks are in most cases nothing to worry about. Try not to dwell on them, relax and go back to sleep again.
However, if you have them regularly and/or severely, you might want to raise it with your primary care doctor. If they think it’s a sign of another disorder, they might ask you to do a sleep study or further tests.
They might also offer to prescribe medication to reduce the frequency and give you advice about adopting more healthy sleep habits.
How can you stop hypnic jerks?
It might not be possible to totally stop them from happening. Accepting them as normal and harmless is perhaps your best option if they aren’t severe.
However, the following self-help ideas might help:
- Cut down on caffeine, nicotine and other stimulants – especially in the evening.
- Reduce how much intense work or exercise you do in the evening. Do exercise in the morning or afternoon instead.
- Eat a balanced, healthy diet.
- Use a comfortable mattress and bedding.
- Sleep in a comfortable position.
- If you suffer from anxiety or stress, do relaxation exercises in bed. One simple breathing exercise is to inhale for a count of 4, hold for 4, then exhale for a count of 4.
- Try not to allow yourself to get too tired. You may understandably have a 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.
If you worry about hypnic jerks, 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, and so a vicious cycle begins.
The key is not to allow the occasional sleep start to disrupt your sleep any more than it has to. Again, try to relax, forget about it and go back to sleep.
Readers’ tips for coping with hypnic jerks
In the comments below, many readers have offered suggestions for reducing their hypnic jerks. So I’ve compiled a list of the most common and interesting ideas.
These don’t all have medical backing, so please take them with a pinch of salt. But you might find the ideas useful if nothing else has helped.
- Try to see the funny side. I do this myself, and think it’s a great way to cope with them if they are particularly strong ones.
- Magnesium supplements have been helpful for some 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.
- Make sure you get enough calcium in your normal diet, or take supplements.
- Assess your current diet. Make sure it’s healthy and balanced. Eat less sugary and salty foods. Eat plenty of fresh fruit and vegetables.
- If you follow a special diet, such as being vegan, pay particular attention to your vitamin and mineral intake, such as the B vitamins. Ensure your diet includes the right quantity, and preferably get your B vitamins through food rather than supplements if possible.
- 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 properly deal with any major source of stress in your life.
- 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.
- Stop doing very intense exercise for a week and see if it improves.
- Try to see them as a sign that you must be falling asleep. So it’s a positive thing as you know you’ll soon be asleep.
- Ask your doctor if any medication you take could be causing it.
- Check if medication you’re taking has the side effects of myoclonus – a surprising amount do.
- Stop taking sleep aids or allergy medication containing antihistamines, which might cause twitches.
- 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.
- Film yourself sleeping or use a sleep tracker. 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 it’s particularly troubling.
- Ensure you have a quiet sleeping environment. It could be a sudden noise which startles you awake.
- Stay hydrated.
- 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 occur repeatedly, get up and have a light snack.
- Have a warm shower before bed. Then do relaxation exercises before getting into bed or 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.
- Try apple cider vinegar. It’s used as a hiccup remedy, so might help with hypnic jerks too.
It’s always 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.