Restless legs syndrome (RLS) is a neurological condition that creates an irresistible urge to move your legs, usually accompanied by uncomfortable sensations that are hard to describe. It affects roughly 7% of adults worldwide, which translates to about 356 million people. The hallmark of RLS is that symptoms strike when you’re at rest and ease up when you move, making it especially disruptive at bedtime.
What It Feels Like
People with RLS describe the sensations in their legs as aching, throbbing, pulling, itching, crawling, or creeping. These aren’t the same as muscle cramps or the pins-and-needles feeling of a leg falling asleep. The discomfort sits deeper, often somewhere between the knee and ankle, and it comes with a compelling need to get up and move. Walking or stretching brings temporary relief, but the sensations typically return as soon as you sit or lie back down.
RLS most commonly affects both legs, though it can show up on just one side. Less often, it spreads to the arms, and in rare cases, the chest or head. The sensations almost always follow a predictable daily pattern: they’re worst in the late afternoon and evening, with a distinct symptom-free window in the early morning hours. This circadian rhythm is one of the defining features of the condition.
Why Nighttime Is the Worst
Because symptoms flare during inactivity and peak in the evening, RLS is often most noticeable right when you’re trying to fall asleep. Many people find themselves pacing the floor, tossing in bed, or constantly shifting their legs to chase relief. The result is difficulty both falling asleep and staying asleep, which can lead to daytime exhaustion, trouble concentrating, and mood changes over time. Long flights, movies, or any situation requiring you to sit still can also become genuinely difficult.
What Causes It
RLS has two core biological drivers: iron levels in the brain and the signaling chemical dopamine. These two systems are closely linked. Iron plays a direct role in how dopamine receptors function, and when iron levels drop in specific brain regions, dopamine signaling becomes impaired. This disruption in dopamine pathways, which are central to both movement and sensory processing, produces the hallmark sensory-motor symptoms of RLS.
Critically, brain iron levels can be low even when blood iron tests come back normal. Only 25% to 44% of people with RLS show iron deficiency on standard blood work. The iron level that matters most is in the brain itself, particularly in the region that produces dopamine. Studies using spinal fluid and brain imaging have confirmed reduced iron in this area among people with RLS, along with impaired dopamine receptor function. This is why treating iron levels is a first step in management, even when your numbers look “fine” by general population standards.
Primary vs. Secondary RLS
Primary RLS runs in families and has a strong genetic component. It tends to start gradually and worsen with age. Secondary RLS, on the other hand, is triggered by another condition or life stage and can sometimes resolve once that trigger is addressed.
Pregnancy is one of the most common triggers. RLS prevalence in pregnant women is two to three times higher than in the general population, with studies estimating that 20% to 27% of pregnant women experience it. The good news: symptoms disappear within days of delivery in about 97% of cases. End-stage kidney disease and peripheral neuropathy are other well-established causes of secondary RLS. Iron deficiency from any source can also trigger or worsen symptoms.
Common Triggers That Make It Worse
Several everyday substances and medications can aggravate RLS or push borderline symptoms into noticeable territory. Alcohol, caffeine, and nicotine are the most frequently cited lifestyle triggers. On the medication side, antihistamines (the kind found in many over-the-counter sleep aids and allergy pills), certain antidepressants that affect serotonin, and anti-nausea drugs that block dopamine can all worsen symptoms. If your RLS started or intensified after beginning a new medication, that connection is worth exploring.
Untreated sleep apnea is another factor that can amplify RLS. The American Academy of Sleep Medicine lists it as an exacerbating condition that should be addressed as part of any RLS treatment plan.
How It’s Diagnosed
There’s no blood test or scan that confirms RLS. Diagnosis is based on five clinical criteria, the most important being: an urge to move the legs accompanied by uncomfortable sensations, symptoms that begin or worsen during rest, relief with movement, symptoms that are worse in the evening or night, and ruling out other conditions that can mimic RLS (such as leg cramps, positional discomfort, or peripheral artery disease). That last criterion was added to improve diagnostic accuracy, since several other conditions can produce similar leg discomfort.
Your doctor will likely order iron studies, including ferritin and transferrin saturation, ideally drawn in the morning after avoiding iron-containing foods and supplements for 24 hours. The ferritin threshold that matters for RLS is different from the general population: supplementation is recommended when ferritin falls at or below 75 ng/mL, a level most labs would flag as “normal.”
Treatment Options
The first step in managing RLS is correcting iron levels if they’re low and removing anything that makes symptoms worse, including alcohol, caffeine, and aggravating medications. For many people with mild RLS, these changes alone bring meaningful relief.
When medication is needed, current guidelines from the American Academy of Sleep Medicine recommend a class of drugs that calm nerve activity (sometimes used for nerve pain and seizures) as the strongest first-line options. These have moved ahead of older dopamine-targeting drugs, which were once the go-to treatment but carry a significant risk of a problem called augmentation. With augmentation, the medication gradually makes the condition worse: symptoms start earlier in the day, become more severe, spread to other parts of the body, and require higher doses to control. This complication develops on average after about six years of dopamine-targeting treatment, though it can appear as early as six months.
Non-Drug Approaches That Help
Several non-medication strategies have evidence supporting their use. Regular exercise, particularly stretching the muscles in the back of the legs, can reduce symptom severity. Warm baths or applying heat packs to the legs before bed helps some people. Pneumatic compression devices, which use inflatable cuffs to rhythmically squeeze the legs, have shown benefit in clinical studies and are available for home use.
Light therapy and acupuncture have also been studied with promising results, though the evidence base is smaller. The consistent theme across non-drug approaches is that they work best as part of a broader strategy alongside iron optimization and trigger avoidance, not as standalone fixes for moderate to severe RLS.