Legs kick while sleeping

The symptoms of restless legs syndrome (RLS) are often difficult to put into words, as each person’s experience with RLS is different. Some people use comparisons, such as “like ants crawling through my legs” or “like soda running through my veins” to try to describe the symptoms and feelings to their heath care professionals. If you answer “yes” to many of the following questions,8 you may have RLS and should talk to your health care professional about your symptoms:

  • When you sit or lie down, do you have a strong desire to move your legs?
  • Does your desire to move your legs feel impossible to resist?
  • Have you ever used the words unpleasant, creepy-crawly, creeping, itching, pulling, or tugging to describe your symptoms?
  • Does your desire to move often occur when you are resting or sitting still?
  • Does moving your legs make you feel better or slow down the symptoms?
  • Do you have more of these symptoms at night?
  • Have you kept your bed partner awake with jerking movements in your legs?
  • Do you ever have involuntary leg movements while you are awake?
  • Are you tired or unable to concentrate during the day?
  • Do any of your family members have similar symptoms?
  • Has a trip to the health care professional not revealed any physical cause for your discomfort?

If you do have RLS, you are not alone! Up to 10 percent of the U.S. adult population may have RLS.1 Many people have a mild or moderate form of the condition, but RLS severely affects the lives of millions of individuals.8 In 2003 the International Restless Legs Syndrome Study Group (IRLSSG), in collaboration with the National Institutes of Health (NIH), identified four main characteristics of RLS that help to make a diagnosis.14 When you go to your health care professional, he or she may use the following criteria to help determine whether or not you have RLS:

  1. You have an urge to move your legs usually accompanied by uncomfortable leg sensations. These sensations are different from muscle cramps and numbness, and are often described as burning, creeping, crawling, aching or tugging. Usually starting in the lower legs, symptoms can spread to other parts of the body, such as the feet, chest, and arms. While often described as uncomfortable or irritating, some people experience pain with these sensations.
  2. Your symptoms are partially or totally relieved by movement. By moving or stretching, the unpleasant sensations can be partially or totally relieved. The kinds of movements that help are often repetitive, such as pacing, rocking or shaking.
  3. Your symptoms begin or worsen during rest such as lying or sitting. Often people will experience RLS symptoms when inactive or not moving around. Lying down, traveling in a plane, or sitting through a movie are examples of situations when RLS may occur. While moving the affected limb can lessen the symptoms, once at rest the symptoms can intensify again.
  4. Your symptoms are worse in the evening or night. There is a typical timing to the intensity or concentration of RLS symptoms. In the early morning, people with RLS often find some relief from the unpleasant sensations. However, as the day continues, symptoms get increasingly worse. Throughout the night, these irritating sensations and feelings often reach their peak.

In order to help you initiate a conversation with your health care professional, we have included an RLS Symptom Diary and RLS Symptom Diary Summary. Click here to record your RLS symptoms.

Pediatric Periodic Limb Movement Disorder (PLMD)

What is Pediatric Periodic Limb Movement Disorder (PLMD)?

PLMD is a neurological disorder (impacting the brain, spine and connecting nerves) that affects a child’s ability to lie still during the night and may impact the duration and quality of sleep. Formerly known as sleep myoclonus or nocturnal myoclonus, PLMD can affect any age or gender.

The brief movements typically occur in the legs every 20 to 40 seconds. They happen in clusters, which can last from a few minutes to a few hours. The PLMD motions can come and go and may not happen every night. The clusters’ time lengths may also vary.

Most children and adolescents are unaware that they are occurring, but stronger motions often wake a child up from sleep. The PLMD movements can be brief muscle twitches, jerking, leg kicks (jerky legs) or cause the foot to flex. Children with PLMD also often have restless leg syndrome (RLS), which is an uncontrollable need to move their legs while awake, typically in response to pain or discomfort.

PLMD and RLS are both unconscious and uncontrollable needs to move the lower limbs. The difference is when they occur – children with PLMD symptoms will be asleep and not aware that they are occurring. RLS symptoms occur when children are awake.

What are the signs and symptoms of Pediatric Periodic Limb Movement Disorder (PLMD)?

Children may wake up in the middle of the night or have chronic insomnia. They may also have difficulty staying asleep, which can cause extreme daytime tiredness and may also lead to other sleep disorders.

Additional symptoms for PLMD may vary and come and go, including the following:

  • Behavioral health issues, including anxiety, anger, depression, hyperactivity, irritability, impulsiveness and poor concentration
  • Erratic leg movements during unconscious sleep (kicking, jerky legs, twitching or flexing the foot)
  • Falling asleep during the day
  • Resisting bedtime
  • Restless sleep
  • Tossing and turning in bed

What are the causes of Pediatric Periodic Limb Movement Disorder (PLMD)?

The exact cause of PLMD is unknown. Experts have suggested the underlying sources may be related to low iron levels (with or without anemia) or problems with nerve conduction (the speed and strength of the nerve signal between cells) due to a chronic disease. Studies haven’t shown consistent reasons behind this neurological disorder.

Risk Factors

Some factors can increase the chances of being diagnosed with PLMD and can make the PLMD symptoms worse, including:

  • Caffeine
  • Chronic illnesses (cancer, diabetes and kidney disease/failure)
  • Genetics/inherited (passed down through generations)
  • Iron deficiency (with or without anemia)
  • Medications (anti-nausea, like metoclopramide/Reglan; antipsychotics like haloperidol/Haldol; Lithium; SSRIs – selective serotonin reuptake inhibitors – like Prozac or Zoloft; and tricyclic antidepressants, like Amitriptyline)
  • Multiple system atrophy (a rare neurological disorder that impacts a body’s involuntary, autonomic functions, including bladder function, blood pressure, breathing and muscle control)
  • Narcolepsy (excessive sleepiness, hallucinations and sleep paralysis)
  • Obstructive sleep apnea (OSA) causes shallow breathing or pauses in breathing during sleep due to an obstruction or block in the throat
  • REM sleep behavior disorder, also known as RBD, that causes the incomplete or absence of paralysis during REM sleep (which allows children to move during their dreams)
  • Restless legs syndrome (RLS)
  • Sleep-related eating disorder (also known as SRED, which are episodes of abnormal eating or drinking patterns during the night)
  • Spinal cord conditions (lesions or spinal blocks) or injuries
  • Uremia (waste products build up in the blood due to problems with kidney function)

Periodic Leg Movements during Sleep (PLMS) & Periodic Limb Movement Disorder (PLMD)

Medications Often Prescribed For PLMS & PLMD

If your symptoms are very frequent or severe, your medical provider may prescribe medications. The medications most frequently prescribed are dopamine agonists or benzodiazepines. Dopamine agonists are commonly prescribed for Parkinson’s disease to control the associated tremors. Benzodiazepines are a class of anticonvulsants, commonly prescribed for seizure disorders. Both of the types of medications work by suppressing abnormal central nervous system activity. Successful management of PLMS has been found with each of the classes of medication.

What Are Natural Treatments For PLMS?

Many people who suffer from mild or moderate PLMS Periodic Limb Movements during Sleep (Periodic Leg Movements during Sleep) can successfully manage their condition with out medication. People often report that relaxation exercises like yoga or meditation can help reduce their symptoms. Some times a hot bath or messaging ones legs before going to sleep will help with the movements as well.

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What Is Periodic Limb Movement Disorder?

It’s bad enough when a sleep condition causes fatigue and disrupted sleep; it’s even worse when that disease starts destroying household linens. Such was the case with a 65-year-old Swiss woman who frequently, and unknowingly, moved her legs while sleeping. In fact, she was so active at night that she rubbed threadbare spots in her bedsheets, where she normally positioned her feet, and had to replace these linens every three months.

Periodic Limb Movement Disorder: A Rough Night

Many people may have rumpled, worn-out bed sheets due to a condition called periodic limb movement disorder (PLMD), sometimes called periodic limb movements in sleep.

During sleep, people with PLMD move their lower limbs, often their toes and ankles and sometimes knees and hips. Periodic leg movements become more common with age — nearly one-third of adults over the age of 60 experience this condition.

Having periodic leg movements “only becomes a disorder if there are symptoms associated with it,” says Ritu Grewal, MD, a sleep physician and pulmonologist with the Jefferson Sleep Disorders Center in Philadelphia. “It only becomes a problem if it disrupts sleep.”

Periodic Limb Movement Disorder vs. Restless Legs Syndrome

Though periodic leg movement disorder shares some similarities with restless legs syndrome, there are also major differences.

Between 80 and 90 percent of patients with restless legs syndrome also have periodic leg movement disorder, Dr. Grewal says. The major difference is that restless legs syndrome occurs while patients are awake and aware of the leg movements; PLMD occurs while the patient is asleep and unaware of what’s going on.

Patients don’t realize what they’re doing at night — it’s their bed partners who usually complain about the leg movements, Grewal says. A clinician must monitor you while you’re asleep in order to diagnose PLMD, which isn’t the case for restless legs syndrome.

Periodic Limb Movement Disorder: Risk Factors

Aside from having restless legs syndrome, other factors that put you at greater risk for periodic leg movement disorder include:

  • Narcolepsy, a condition in which people suddenly fall asleep during the day, typically for a few seconds or minutes
  • Iron deficiency or conditions associated with low iron, such as pregnancy and kidney disease
  • Nerve damage, such as from diabetes
  • Certain medication, like antihistamines and antidepressants

Recent research suggests that left-handedness may also be a factor in the severity of PLMD. One study from the University of Toledo Medical Center in Ohio found that 94 percent of left-handed people with PLMD experienced movements on both sides of their body while sleeping, compared with just 69 percent of right-handed patients. The rest had unilateral, or one-sided, movements.

Periodic Limb Movement Disorder: Treatment

Doctors can treat PLMD with a variety of medication, including ropinirole (Requip) and pramipexole (Mirapex), which are also used for restless legs syndrome. Your doctor may also suggest iron supplements if necessary, as well as supplemental magnesium and folic acid.

Regular exercise may be helpful in treating PLMD and reducing symptoms. In addition, resting in an environment that’s conducive to good sleep may be beneficial, according to the American Sleep Association. Having a quiet room and a comfortable bed and pillow can help you quickly reach a stage of sleep in which leg movements are less likely to occur.

You may also ease your symptoms by avoiding caffeinated and alcoholic beverages, tobacco, and antihistamines, particularly late in the day.

If you suspect that you have PLMD, visit a doctor specializing in sleep disorders. Warning signs include sleeping the right amount of hours at night and still feeling tired the next day, and having a bed partner who complains that you continuously kick or twitch your legs, Grewal says. Of course, threadbare spots at the bottom of your sheets can also be a sign of PLMD.

Periodic Limb Movement Disorder (PLMD) in Adults

What is periodic limb movement disorder (PLMD)?

Periodic limb movement disorder (PLMD) is a condition that was formerly called sleep myoclonus or nocturnal myoclonus. It is described as repetitive limb movements that occur during sleep and cause sleep disruption. The limb movements usually involve the lower extremities, consisting of extension of the big toe and flexion of the ankle, the knee, and the hip. In some patients, the limb movements can occur in the upper extremities as well.

The limb movements occur most frequently in light non-REM sleep. The repetitive movements are separated by fairly regular intervals of 5 to 90 seconds. There can be significant night-to-night variability to the frequency of limb movements.

Who gets periodic limb movement disorder (PLMD)?

Many individuals have periodic limb movements in sleep (PLMS). This is observed in about 80% of patients with restless legs syndrome (RLS). PLMS can occur in over 30% of people aged 65 and older and can be asymptomatic. PLMS are very common in patients with narcolepsy and REM behavior disorder, and may be seen in patients with obstructive sleep apnea and during PAP therapy initiation.

True PLMD – the diagnosis of which requires periodic limb movements in sleep that disrupt sleep and are not accounted for by another primary sleep disorder including RLS – is uncommon.

PLMD has been less extensively studied than RLS. The exact prevalence is unknown. It can occur at any age; however, the prevalence does increase with increasing age. Unlike RLS, PLMD does not appear to be related to gender.

As with RLS, some medical conditions are associated with PLMD. These include uremia, diabetes, iron deficiency, OSA, and spinal cord injury.

What causes periodic limb movement disorder (PLMD)?

The exact cause of PLMD is unknown. However, several medications are known to make PLMD worse. These medications include some antidepressants, antihistamines, and some antipsychotics.

What are some of the symptoms of periodic limb movement disorder (PLMD)?

Most patients are actually not aware of the involuntary limb movements. The limb jerks are more often reported by bed partners. Patients experience frequent awakenings from sleep, non-restorative sleep, daytime fatigue, and/or daytime sleepiness.

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Periodic limb movements in sleep are repetitive movements, most typically in the lower limbs, that occur about every 20-40 seconds. If you have PLMS, or sleep with someone who has PLMS (also referred to as PLMD, periodic limb movement disorder), you may recognize these movements as brief muscle twitches, jerking movements or an upward flexing of the feet. They cluster into episodes lasting anywhere from a few minutes to several hours.

The exact cause of PLMS is still unknown. Scientists believe that the underlying mechanisms probably involve factors in the nervous system, although studies have not revealed any consistent abnormalites. PLMS are not considered medically serious. They can, however, be implicated as a contributing factor in chronic insomnia and/or daytime fatigue because they may cause awakenings during the night. Occasionally, PLMS may be an indicator of a serious medical condition such as kidney disease, diabetes or anemia.


Individuals with PLMS may also experience restless legs syndrome (RLS), an irritation or uncomfortable sensation in the calves or thighs, as they attempt to fall asleep or when they awaken during the night. Walking or stretching may relieve the sensations, at least temporarily. However, research also shows that many individuals have PLMS without experiencing any symptoms at all. It’s not unusual for the bed partner to be the one who’s most aware of the movements, since they may disturb his/her sleep.


A number of medications have been shown to be effective in treating PLMS, but treatment is only necessary when PLMS are accompanied by restless legs (RLS), insomnia or daytime fatigue.


Seek professional medical advice. You may wish to begin by consulting your family physician or find a sleep professional.

What the Feet and Legs Say About Us

Our feet and legs, often neglected in the study of body language, transmit a lot of valuable information about what we are sensing, thinking, and feeling. We pay so much attention to the face and other parts of the body, that we forget the importance of these vital appendages.

It’s a mistake most of us make, and we shouldn’t, because in many ways the feet and legs are the most accurate part of our body. They reflect our true emotions and intentions, in real time, unlike our face and other parts of the body, and they can be instrumental in the detection of deception.

Over millions of years, our limbic system made sure that our feet and legs reacted instantly to any threat or concern; their reliability has assured, in part, our survival. Someone walks up to us late at night while we are at the ATM machine and our legs tighten up, and our feet orient towards an escape route, preparing us to flee if necessary.

In the same way, our limbic brain tells our feet not to walk too close to the edge of the canyon, so we don’t. We cross our legs when we are comfortable in the elevator, yet when a group of dodgy strangers enter, we immediately uncross our legs so we are able to flee if necessary. We are talking to a good friend and suddenly we notice one of the feet is pointed down the street. No need to ask, they have to go, they are running late for an appointment. Want to know if two people talking in the hallway like you or want you to join them? If their feet don’t move to welcome you and they only rotate at the hips, just keep on walking by. When a relationship is turning sour, there will be less and less foot contact. They may hold hands in public but their feet simply avoid each other.

These are examples of limbic reactions, reflected in the feet and legs, to situations, feelings, and intentions. They are very timely and accurate.

Similarly, a child may be sitting down to eat, but if he wants to go out and play, notice how his feet sway, how they stretch to reach the floor from a high chair, even when he has not yet finished with his meal. You can try to hold him in place, but he will wiggle and his feet will turn towards the nearest desired exit—an accurate reflection of where his feet and he wants to go. This is an intention cue, and we have several that we use to reflect our needs to do something.

Because our feet and legs are so honest, I place special emphasis in what they communicate while assessing for deception. Most people focus on the face, but unfortunately, our faces are very good at deceit. From an early age we are told, “don’t make that face,” even though we hate what we are being fed. As we get older it continues, we put on a “party face” at the request of our significant other, or we smile because the culture we come from requires it. And so we fake what we feel or think with our faces (thus a “poker face”) for social harmony. We also do it to protect ourselves from being discovered when we are being dishonest. Our feet and legs, because they are necessary for survival, make no such concessions.

As I state in my book, What Every Body is Saying: “Nervousness, stress, fear, anxiety, caution, boredom, restlessness, happiness, joy, hurt, shyness, coyness, humility, awkwardness, confidence, subservience, depression, lethargy, playfulness, sensuality, and anger can all manifest through the feet and legs.” When I was doing interviews in the FBI, I focused on the feet and legs precisely because they do reveal so much information about what is in the mind and liars think about their facial displays but not their legs and feet.

In 25 years observing and cataloguing behavior for the FBI, I noticed that when people begin to lie, they often distance themselves (part of the flight-distancing response, see FBI-LEB article) by standing further away from you. Or, they point their feet away from you but turn towards you with their torso. It looks okay on first inspection, but these are distancing behaviors which reveal quite a lot about what is going on in their brain.

Liars tend not to emphasize. They know what to say, but not the emotions that go with what they are saying (see FBI-LEB article), so we see fewer gravity-defying behaviors when they speak. Truthful people tend to defy gravity by rising on the balls of their feet when they are emphasizing a point, or arching their eyebrows. Liars don’t do that, because gravity defying behaviors are limbically derived—emotional exclamations we express through our body language, which they lack.

When we are telling the truth, our feet tend to take a wider, sturdier stance. The minute we feel insecure about what we are saying or if we are lying, our feet tend to come together. Again, this is a limbic response tethered to how we feel (insecure) about what is being said. When we aren’t mentally sure, it is reflected in our legs and feet.

When lying, the deceiver is concerned about being detected and what you may observe is that concern sometimes drives what I have come to call the “Ankle Quiver.” Here, the ankle begins to twitch causing the person to rock the foot sideways back and forth (bottom side to edge of foot). A truthful person has no such need to pacify themselves by this repetitive rocking behavior, but a liar may find such “under the table” behaviors to be self-soothing.

Lastly, and these are obviously not all the foot and leg behaviors to note, look for the person who makes a statement and then does a leg cleanse. By rubbing his hands (sometimes multiple times) on the top of his legs while seated, this pacifies the individual who is deceptive or harboring guilty knowledge. This often occurs when very direct, poignant questions are asked, causing a high degree of discomfort.

For more insight into the importance of the feet and the legs in assessing for deception, Chapter three in What Every Body is Saying explains in greater detail how we can use the feet and legs to decipher human behavior. So as you ponder the behaviors of others to determine what they are thinking, feeling, or intending, remember that the feet and the legs are valuable in that quest because they don’t let us down in their accuracy.

As we give up our bodies to sleep, sudden twitches escape our brains, causing our arms and legs to jerk. Some people are startled by them, others are embarrassed. Me, I am fascinated by these twitches, known as hypnic jerks. Nobody knows for sure what causes them, but to me they represent the side effects of a hidden battle for control in the brain that happens each night on the cusp between wakefulness and dreams.

Normally we are paralysed while we sleep. Even during the most vivid dreams our muscles stay relaxed and still, showing little sign of our internal excitement. Events in the outside world usually get ignored: not that I’d recommend doing this but experiments have shown that even if you sleep with your eyes taped open and someone flashes a light at you it is unlikely that it will affect your dreams.

But the door between the dreamer and the outside world is not completely closed. Two kinds of movements escape the dreaming brain, and they each have a different story to tell.

Brain battle

The most common movements we make while asleep are rapid eye-movements. When we dream, our eyes move according to what we are dreaming about. If, for example, we dream we are watching a game of tennis our eyes will move from left to right with each volley. These movements generated in the dream world escape from normal sleep paralysis and leak into the real world. Seeing a sleeping persons’ eyes move is the strongest sign that they are dreaming.

Hypnic jerks aren’t like this. They are most common in children, when our dreams are most simple and they do not reflect what is happening in the dream world – if you dream of riding a bike you do not move your legs in circles. Instead, hypnic jerks seem to be a sign that the motor system can still exert some control over the body as sleep paralysis begins to take over. Rather than having a single “sleep-wake” switch in the brain for controlling our sleep (i.e. ON at night, OFF during the day), we have two opposing systems balanced against each other that go through a daily dance, where each has to wrest control from the other.

Deep in the brain, below the cortex (the most evolved part of the human brain) lies one of them: a network of nerve cells called the reticular activating system. This is nestled among the parts of the brain that govern basic physiological processes, such as breathing. When the reticular activating system is in full force we feel alert and restless – that is, we are awake.

Opposing this system is the ventrolateral preoptic nucleus: ‘ventrolateral’ means it is on the underside and towards the edge in the brain, ‘preoptic’ means it is just before the point where the nerves from the eyes cross. We call it the VLPO. The VLPO drives sleepiness, and its location near the optic nerve is presumably so that it can collect information about the beginning and end of daylight hours, and so influence our sleep cycles.

As the mind gives in to its normal task of interpreting the external world, and starts to generate its own entertainment, the struggle between the reticular activating system and VLPO tilts in favour of the latter. Sleep paralysis sets in. What happens next is not fully clear, but it seems that part of the story is that the struggle for control of the motor system is not quite over yet. Few battles are won completely in a single moment. 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.

Some people report that hypnic jerks happen as they dream they are falling or tripping up. This is an example of the rare phenomenon known as dream incorporation, where something external, such as an alarm clock, is built into your dreams. When this does happen, it illustrates our mind’s amazing capacity to generate plausible stories. In dreams, the planning and foresight areas of the brain are suppressed, allowing the mind to react creatively to wherever it wanders – much like a jazz improviser responds to fellow musicians to inspire what they play.

As hypnic jerks escape during the struggle between wake and sleep, the mind is undergoing its own transition. In the waking world we must make sense of external events. In dreams the mind tries to make sense of its own activity, resulting in dreams. Whilst a veil is drawn over most of the external world as we fall asleep, hypnic jerks are obviously close enough to home – being movements of our own bodies – to attract the attention of sleeping consciousness. Along with the hallucinated night-time world they get incorporated into our dreams.

So there is a pleasing symmetry between the two kinds of movements we make when asleep. Rapid eye movements are the traces of dreams that can be seen in the waking world. Hypnic jerks seem to be the traces of waking life that intrude on the dream world.

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