Everything You Need to Know About Sleep-Related Movement Disorders

Do you have difficulty falling asleep at night? Perhaps your legs or another part of your body always seems to want to move but if you don’t move, it’s almost painful. If so, you could have a sleep-related movement disorder, like restless leg syndrome.


What are sleep-related movement disorders?

Sleep movement disorders include any type of condition in which a person is moving or feels the desire to move significantly during sleep or before falling asleep. This makes it difficult to fall and stay asleep. One of the most common conditions, restless leg syndrome, occurs in about 7 to 10 percent of the U.S. population, according to the National Institute of Neurological Disorders and Stroke. Below are some of the most common types of sleep movement disorders.

Restless Leg Syndrome (RLS)

A person with restless leg syndrome, or RLS, has an overwhelming and uncomfortable urge to move their legs while resting, especially at night. Moving the legs on purpose or walking will resolve the sensation, but it will return upon trying to rest again. This often makes it difficult  to get comfortable enough to fall asleep. Sometimes, people with RLS will not be aware that they move their legs during their sleep as well.

Restless Leg Syndrome Causes

Though not fully understood, people with this neurological condition tend to have relatives who are also affected. People with iron deficiency or kidney disease also can develop RLS. It often develops in adults after the age of 45 but can occur at any time.

Risks if Left Untreated

For some people, RLS symptoms may come and go or resolve over time. However, the symptoms are less likely to improve for those with severe RLS, a family history of RLS, or who developed RLS at an older age without treatment. If left untreated , it can impact sleep quality which can impact overall health, concentration, mental clarity, and reaction times.

Treatment Options

There’s no cure for this condition, however, it can be treated to improve symptoms. Iron supplements and neurological medications are commonly used to treat restless leg syndrome.

Sleep-Related Leg Cramps

Sleep-related leg cramps, or nocturnal leg cramps, are sudden, painful muscle cramps in the calf, thigh, or foot that disrupt sleep. Most cramps last several seconds, but some can last several minutes, making them difficult to ignore. Some people with nocturnal leg cramps suffer from this type of sudden, uncontrollable cramping nightly, while others may only have it a few times a year. This condition becomes more common with age.

Sleep-Related Leg Cramps Causes

In most cases of sleep-related leg cramps, no known cause is found. These cramps are more common in people who have structural changes (like flat feet), prolonged periods of sitting, dehydration, low potassium or magnesium, hormone imbalances like diabetes or hypothyroidism, or muscle fatigue from exercise.

Risks if Left Untreated

Pain is the most common problem associated with sleep leg cramps, but they can also lead to soreness that limits mobility and poor sleep quality.

Sleep-Related Leg Cramp Treatment Options

Correcting the underlying cause is the best treatment. It may also be important for a person to stretch before bed and to take medications  that minimize muscle pain.


Bruxism is grinding or clenching of the teeth during sleep. A person may not know they are doing this, but feel jaw pain and discomfort once they wake up.  Some people will produce a strong sound as they grind their teeth. Bruxism is more common in childhood and becomes less common with age.

Bruxism Causes

It’s not fully understood why this condition occurs, though people with other sleep disorders such as obstructive sleep apnea or parasomnias are more likely to have bruxism.

Risks if Left Untreated

 If left untreated, damage to tooth surfaces can occur. In severe cases, head and neck pain, dental fractures, or other mouth injuries are possible.

Bruxism Treatment Options

The immediate solution to protect tooth health is to use a device placed in the mouth to minimize tooth-on-tooth contact, such as a mouthguard.

Rhythmic Movement Disorder

Sleep-related rhythmic movement disorder, or rhythmic movement disorder, is a condition that primarily affects  children by causing them to experience involuntary rhythmic body movements when tired or falling asleep. These movements, which may include body rocking, head rolling, or leg banging, are a normal development in early childhood. However, if the movements cause self-harm or disrupt normal sleep, then they are classified as rhythmic movement disorder.

Rhythmic Movement Disorder Causes

In children, these actions can feel soothing, often related to the rocking they felt as a baby.

Risks if Left Untreated

There are usually no risks to rhythmic movements unless it prevents a child  from sleeping or causes self-injury. Almost all childhood cases will self-resolve over time.

Rhythmic Movement Disorder Treatment Options

If there is a concern for injury, maintaining a safe and protected sleep environment is necessary.

Periodic Limb Movement Disorder (PMLD)

Periodic limb movement disorder (PMLD) is defined by frequent uncontrollable movements of a limb, usually the leg, which disturbs sleep. These tend to be simple, repetitive movements every 20 to 40 seconds in  one leg, both legs, or alternating between the left and right legs. Because these movements disrupt the person’s sleep, and possibly their bed partner’s sleep, people with PMLD often have excessive daytime fatigue. PMLD can only be diagnosed when other sleep-related movement disorders are not present, including RLS.

Periodic Limb Movement Causes

The cause of PMLD is not well understood, but some medications, stress, iron deficiency, and high caffeine intake can increase the risk for PMLD  symptoms.

Risks if Left Untreated

As PMLD causes poor sleep and daytime fatigue, when left untreated sufferers may experience poor concentration and memory, depression, and attention-deficit hyperactivity disorder (ADHD).

Periodic Limb Movement Treatment Options

Reducing caffeine consumption and treating any iron deficiency may help reduce the frequency of PMLD episodes. Antidepressant medications may  worsen this condition, which means doctors may try to limit their use if possible. Neurological medications may also be used to help reduce symptoms.

If you suspect you have a sleep-related movement disorder, see a doctor

Sleep-related movement disorders may not be common, but can impact quality of life. For that reason, they should be investigated, properly diagnosed, and treated by a sleep specialist. Doing so can improve overall health and well being, especially through improved quality of sleep.

Sabina Hoque, MD MPH

Medically Reviewed

Sabina Hoque, MD MPH is a board-certified internal medicine physician with 10 years of clinical experience. In addition, she holds a masters in Public Health and has significant experience in teaching and biostatistics. She enjoys distilling complex medical information for audiences of varying levels of health literacy.

All content published on the HealthySleepGuide.com website is credited for informational purposes only. The information should not substitute as medical advice, diagnosis, or treatment. Always consult your doctor or qualified health professional with any questions regarding your health.