There are a few possible reasons why people may flinch or move suddenly during sleep. These include:
Sleep starts or hypnic jerks: These are sudden, brief contractions of the muscles that occur as a person is falling asleep. They are not harmful and are considered a normal part of the sleep process.
Nighttime leg cramps: Leg cramps, especially in the calf muscles, can cause sudden movements or jerking during sleep. These cramps can be caused by a variety of factors, including dehydration, electrolyte imbalances, and certain medications
Nightmares or night terrors: These are vivid, disturbing dream experiences that can cause people to move or cry out in their sleep. They are more common in children but can also occur in adults.
REM sleep behavior disorder (RBD): This is a disorder in which people act out their dreams during REM sleep, which can involve flinching, twitching, or even getting out of bed.
Sleep disorders: Certain sleep disorders, such as restless legs syndrome (RLS) and periodic limb movement disorder (PLMD), can cause people to move or jerk during sleep. These disorders can disrupt sleep and cause fatigue and other symptoms during the day.
It's important to note that in most cases, flinching or moving during sleep is a normal part of the sleep process and is not harmful. However, if you are experiencing frequent flinching or movement during sleep that is disrupting your sleep, or if you have other symptoms such as daytime fatigue or difficulty staying asleep, it may be a good idea to talk to your doctor or a sleep specialist. They can help determine the cause and recommend appropriate treatment if necessary.
Periodic Limb Movement Disorder
The correct term for sudden flinching motions during sleep is ‘Periodic Limb Movement Disorder’ (PLMD). They are repetitive movements during sleep, that are most typically in the legs or feet, they tend to occur every 20-40 seconds. If you have PLMD, or sleep with someone who that has PLMD, you may recognise these movements as brief muscle twitches and jerking movements.
The exact cause of Periodic Limb Movement Disorder is still unknown. Scientists believe that it may have something to do with the nervous system, although studies have not revealed any consistent abnormalities. PLMD is not considered to be medically serious. Although it can be linked with chronic insomnia as well as daytime fatigue, because it may cause awakenings during the nighttime.
People with Periodic Limb Movement Disorder may also experience Restless Legs Syndrome (RLS) too. This is an irritation or uncomfortable sensation in the calf or thigh area, as they attempt to fall asleep or when they wake up during the night. Walking or stretching may relieve the sensations, but only for a temporary basis. Research has also shown that many individuals can suffer from PLMD without experiencing any symptoms at all.
A number of medications have been shown to be effective in treating PLMD, but treatment is only necessary when PLMD are accompanied by restless legs (RLS), insomnia or daytime fatigue. If you are finding that Periodic Limb Movement Disorder is heavily affecting your sleep, then you may want to consider consulting a doctor or sleep therapist.
Overall, Periodic Limb Movement Disorder is quite a common sleeping disorder and isn’t something to be too concerned about. But in some cases it can be more serious and may lead to other sleep related issues, like insomnia. So if PLMD is having a negative effect on your sleep, we would advise that you contact your doctor.
