The symptoms of restless legs syndrome sound like the plot of a horror movie. If you have this condition, you might sink into bed at the end of each day aching for a good night’s sleep. Then it begins. An irresistible urge to move your legs won’t allow you any peace. You feel creeping, crawling, tingling, aching, or twitching sensations in your lower extremities, making it almost impossible to sleep. If you don’t have restless legs syndrome (RLS for short), this may sound unimaginable. But for people with intense cases of RLS, this might be just another typical night.
In 1685, a doctor named Sir Thomas Willis recorded the first written case about RLS, according to a 2012 review in Sleep Medicine Reviews. Fast forward to 1945, when a doctor named Karl-Axel Ekbom came up with the name restless legs syndrome. Though both milestones happened some time ago, doctors are still searching for a definitive cause and cure for this condition, alternatively called Willis-Ekbom disease. Here are nine facts explaining what doctors know so far about this baffling disorder and which mysteries still need investigating.
1. Restless legs syndrome causes unusual physical sensations and movement.
RLS is a neurological disorder involving a powerful impulse to move body parts, usually because of uncomfortable sensations, according to the National Institute of Neurological Disorders and Stroke (NINDS). Although this condition nearly always affects the legs—they’re right there in the name, after all—it’s also possible for RLS to affect areas like the arms, chest, and head, according to the NINDS.
Sometimes RLS sensations are so weird that people have trouble describing them, according to the Mayo Clinic. With that said, the following descriptions are generally agreed upon to come pretty close:
- Aching
- Crawling
- Creeping
- Electric feelings
- Itching
- Pulling
- Throbbing
These symptoms may affect up to 7 to 10 percent of people in the United States, according to NINDS estimates. It can begin at any age, but RLS becomes more common as people get older, the Mayo Clinic says. If symptoms start before age 40, it’s more likely that there’s a genetic component involved (more on that later).
It’s possible to experience these symptoms at varying levels of severity every night, a few times a week, or even less often than that, according to the NINDS. However, RLS typically becomes more frequent and severe with age.
2. Moving the legs can temporarily tame these odd feelings.
It’s only natural that if you have an uncontrollable urge to move your legs, you’re going to do just that. Interestingly enough, moving the body parts affected by RLS can get rid of or lessen the symptoms temporarily, according to the Mayo Clinic.
This is why many people with RLS will do things like pace, tap their feet, stretch, and generally move their legs as much as possible when they have symptoms. But the sensations return once the motion stops, which is a huge reason why this condition can be so life-disrupting depending on its severity.
3. RLS can make it almost impossible to sleep well.
In a cruel twist, symptoms are most likely to strike when you’re most desperate for rest: as you try to go to sleep. Since most people work during the day and sleep at night, symptoms tend to arise in the late afternoon and evening, becoming exacerbated at night when a person is at rest, the NINDS explains. (This is because RLS appears to follow a person’s circadian rhythm.)
As such, RLS can lead to issues like excessive daytime sleepiness that can put stress on relationships and work. It can also harm mental health. Feelings of frustration and helplessness are only to be expected when your own body robs you of sleep, and that can eventually contribute to conditions such as depression and anxiety.
This chronic lack of sleep is part of why there’s fervent interest around whether or not RLS may increase the risk of physical health issues such as cardiovascular disease. Although the existence of an association is still up for debate, some researchers believe that the connection lies, at least in part, in a lack of sleep. (This could be due to a constellation of factors, like how a lack of sleep is a risk factor for obesity, which can then contribute to heart disease.)
4. RLS can cause another sensory issue called periodic limb movements of sleep.
In addition to the (sometimes literal) pain associated with falling asleep, it’s estimated that more than 80 percent of individuals with RLS also experience periodic limb movements of sleep (PLMS), the NINDS says. These are basically involuntary leg and/or arm spasms that can happen as often as every 15 to 40 seconds all night long, causing constant disruptions that might further harm your sleep.
It appears as though blood pressure and heart rate spike temporarily during these jerky movements, which is why some experts posit that PLMS and, relatedly, RLS may raise a person’s risk of heart issues over time.
5. Primary RLS happens with no known cause.
“When you’re dealing with the brain, it’s very complex,” John Winkelman, M.D., Ph.D., chief of the Sleep Disorders Clinical Research Program at Massachusetts General Hospital, tells SELF. “There are no simple explanations.”
With that in mind, let’s talk about possible causes of primary (or idiopathic) RLS, which is when doctors can’t pinpoint an underlying reason why someone has this condition.
One major theory revolves around the neurotransmitter dopamine, which is necessary for creating and maintaining normal muscle movement, according to the NINDS. Some experts think malfunctions in the dopamine pathway can create the uncontrollable movements involved in disorders like RLS.
It also appears that there is a hereditary element. A 2017 study in The Lancet Neurology analyzed DNA from 428,534 people, concluding that there are at least 19 genetic risk variants for RLS. Additional research is needed to understand the link between these genes and the biological component of RLS.
6. Secondary RLS is tied to specific risk factors.
For instance, doctors believe that an iron deficiency may predispose a person to RLS. One theory is that low levels of iron can impact dopamine signaling; another is that RLS genetic risk variants may affect iron stores.
This iron connection may be part of why pregnancy is a major risk factor for RLS. Pregnant people are more at risk of iron deficiency because their blood volume increases by 20 to 30 percent, calling for more iron to create hemoglobin that can send oxygenated red blood cells all over the body. Rising hormones in pregnancy, such as estrogen and progesterone, may also contribute by impacting dopamine production, though the scientific jury is still out. In any case, if someone develops RLS during pregnancy, the symptoms typically subside after giving birth, according to the NINDS.
Taking specific medications is yet another risk factor. Some antidepressants that increase serotonin (including the popular antidepressant class selective serotonin reuptake inhibitors, or SSRIs), anti-nausea drugs, and antihistamines may bring about or worsen RLS, the NINDS says. All of these mechanisms appear to be tied to those critical dopamine pathways.
7. RLS diagnosis primarily hinges on symptoms.
There is no lab test to detect RLS, the Mayo Clinic explains. Instead, RLS is diagnosed based on a set of symptoms defined in 2003 guidelines published in Sleep Medicine:
- A strong urge to move the legs, which typically occurs with additional unpleasant sensations (but doesn’t always)
- The need to move, which happens during periods of rest or inactivity
- Temporary relief with movement
- Worse symptoms in the evening and at night (or symptoms only in the evening and at night)
Your doctor may also perform medical exams like a blood test to check for an iron deficiency, according to the Mayo Clinic.
8. Treatment for RLS revolves around relieving symptoms.
To start, your doctor may recommend non-pharmaceutical tactics to ease your RLS. Here are some ideas from the Mayo Clinic and the NINDS:
- Cutting out or reducing caffeine, nicotine, and other substances that can affect your sleep
- Exercising (but not too soon before bed, when it might energize you)
- Taking a warm bath and massaging your legs to loosen up your muscles
- Applying heat and cold packs to your legs
- Trying to stick with a regular sleep schedule if at all possible
It may also help to try to organize your day around your symptoms when possible, like by scheduling sedentary activities such as traveling or watching a movie during the times when your RLS tends to be least active. (Since RLS appears to follow circadian rhythms and most people work in the day and rest at night, this may be in the morning for you. However, for those who, say, do shift work, RLS could actually be worse in the morning and better at night.)
Then there are the medical treatments. Some drugs work to raise dopamine levels in the brain, the NINDS says, although they may actually intensify symptoms in the long-term. Anti-seizure drugs that can calm muscle movements are also gaining prominence in RLS treatment. And people with proven iron deficiencies may find some relief in doctor-approved supplementation.
Sometimes doctors prescribe opioids for RLS as they tend to be successful in alleviating some of the discomfort, but with stricter regulations and the growing concern over addiction, this option is becoming more of a last resort. The same goes for the class of sedatives known as benzodiazepines, which can help you sleep but can counterintuitively also cause problems like daytime sleepiness, the NINDS says.
Finally, there are devices approved by the U.S. Food and Drug Administration (FDA) to relieve RLS symptoms. Relaxis is a vibration pad that goes under the legs, and Restiffic is a pressure wrap that goes around the legs or feet.
9. There’s hope on the horizon for people with RLS.
In the past, many people with RLS had no idea what was happening, Dr. Winkelman says. Those with this condition often feared what others would think if they tried to explain these strange phantom resting pains, he explains.
Now, Dr. Winkelman says, awareness continues to increase due to more research and newer treatments. Although scientists haven’t fully figured out this condition, there’s less mystery surrounding RLS, so more people are seeking—and hopefully getting—the help they need.
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