Hypnic Jerks: Why Do We Twitch In Our Sleep?

Twitching in your sleep. We’ve all been there. You’re about to drift off into the land of nod when suddenly your body twitches or jumps, and your limbs, for some reason, jerk in random directions. Formally called hypnic jerks, they may cause confusion or even amusement, but have you ever wondered what causes this bizarre phenomenon? We look into scientific theories to find out what causes jerking and twitching in sleep.

Also known as hypnagogic jerks, “sleep starts”, or commonly sleep twitching, are involuntary muscle contractions that some people experience when falling asleep. These are also a type of sleep myoclonus, which scientifically is the name for the jerking movements your body makes during sleep.

They got the name because these twitches usually occur while you are in the hypnagogic state, between being awake and asleep. They tend to occur in stage 1 or 2 of sleep and disappear in REM sleep when you are fully sleeping.

According to the BBC, hypnic jerks are most common in children and are unconscious muscle spasms that occur as you drift off to sleep. They can be completely random or induced by specific triggers, such as sound or light.

Sleep expert Dr. Natalie Dautovich states:

As we transition from wakefulness to sleep, we experience a hypnagogic state of consciousness. During this state, we can experience unique phenomena including a hypnic jerk that accompanies a falling sensation. During sleep, restlessness centered in the legs, or periodic jerking of the legs can be symptoms of sleep disorders.

Sleep jerking can be mild and hardly noticeable; other times, it can wake you up. Don’t worry if you or a partner experiences sleep twitching, as these are common, occur randomly, and aren’t dangerous. Alongside hypnic jerks, you might also feel the common sensation of falling or tripping, a sensory flash, or a vivid dream which causes you to jerk.

Although these movements can correlate with certain dreams, such as falling or tripping up, hypnic jerks do not usually reflect what is happening in the dream world. Instead, your brain builds dreams based on what is happening in the real world. In other words, as you jerk or twitch in your sleep, your brain corresponds with your body’s movements, and you conjure up a falling scenario in your head. This is similar to when your alarm clock goes off, and you incorporate the sounds into your dreams.

Everyone experiences involuntary muscle contractions that cause twitching during the first stage of sleep when their muscles are relaxing. However, it is more common for men to twitch in their sleep than for women.

Researchers from Innsbruck, supported by the FWF, closely examined 100 individuals while sleeping. 60 women and 40 men participated. They found that “during REM sleep and non-REM sleep, several muscle twitches per hour were recorded in healthy individuals – with a greater number in men than in women.”

Whilst studies prove twitching in sleep is more common in men, there is no definitive answer as to why. It could be sleep deprivation, stress, anxiety, dreams, or just their body coming to a rest.

The BBC suggests that random hypnagogic jerks are your last attempts at regaining control as your body drifts off to sleep, stating:

‘As sleep paralysis sets in, remaining daytime energy kindles and bursts out in seemingly random movements. In other words, hypnic jerks are the last gasps of normal daytime motor control.’

One interesting hypothesis behind hypnagogic jerks claims that they occur when nerves ‘misfire’ during the body’s transition from being awake to asleep. Another idea links them back to an ancient primate reflex, suggesting the brain misinterprets the body’s relaxation as a cue that the sleeping primate is about to fall out of a tree and thus causes the muscles to react immediately.

While there still isn’t enough research to know the exact reasons or clear causes of sleep twitching, there are some theories. Sleep jerking occurs in most people and can be random or consistent without any underlying explanation. But they may be caused by:

• Extreme tiredness or sleep deprivation
• Sleeping in an uncomfortable position
• Having stimulants before going to bed (these may also increase the frequency of twitching while asleep)
• Stress and anxiety

While there is no clear explanation for what causes twitching in sleep, a few lifestyle changes might help to reduce them. Start by avoiding additional light or sound in your bedroom, and try to wake up naturally without an alarm clock. You can also try the following tips to help you sleep at night and reduce twitching:

1. Try to get at least 8 hours of sleep

To avoid being overtired or sleep-deprived, aim to get at least 8 hours of rest a night. To help, ensure that your room is dark, quiet, and comfortable.

2. Create a routine

Give yourself an hour before bed to wind down, away from screens, as blue light will naturally keep you awake longer. Create a bedtime routine to help you relax and reduce stress before sleeping. It will also help if you get into a habit of doing this consistently every night.

You can also create a morning routine to make getting out of bed easier. Try to wake up at the same time each morning and start your morning off without screens, as that will only kickstart your stress levels for the day.

3. Avoid late-night exercise

Exercising too close to bedtime can stop your body from relaxing when it’s time to sleep. Here’s what Healthline had to say on the matter:

In general, if you’re going to exercise at night, it’s best to do light to moderate-intensity activity. This level of activity may help you fall asleep faster and get better quality sleep. It’s also important to complete your workout at least 1 hour before bedtime. If possible, aim to finish at least 90 minutes before you head to bed. This will give your body enough time to wind down.

3. Avoid caffeine

Caffeine (and other stimulants) are great for keeping you awake, so we recommend eliminating caffeine later in the day. Here’s what CNBC had to say:

Caffeine can disrupt your sleep up to six hours after consuming it, leading to an hour or more lost in rest, one study found.

So if you want to start winding down and going to bed at 9 p.m., drinking coffee after 3 p.m. is a bad idea. Some health experts recommend people stop drinking coffee as early as 2 p.m.

4. Reduce stress

A highly stressful lifestyle can play havoc with your sleep. You are likely to be more alert, which makes you much more prone to jerks and involuntary muscle twitches. If you’re struggling to reduce stress, check out our podcast on how to sleep when you’re stressed.

If you struggle with stress or anxiety, addressing this issue may help reduce sleep twitching. Try to destress during the day and use affirmations and calming techniques to take away any anxious thoughts. Guided meditation, breathing exercises, or relaxing medication can help you wind down and sleep.

Random hypnic jerks and twitches in sleep are completely normal and quite common. They usually don’t indicate an underlying health issue and are simply muscle contractions during sleep that range from mild to intense. You can take many steps to help relax before bed, and a few changes to your bedtime routine can help you stop twitching in sleep and leave you feeling well-rested. Try some of the above suggestions or check out our podcast on how routine affects sleep for advice and tips from Dr. Pixie Mckenna and Professor Kevin Morgan, a Professor of Psychology.