Restless Legs at Night: Causes and What Helps

Restless legs syndrome (RLS) is one of the most common neurological conditions affecting sleep, affecting roughly 5 to 10% of adults, yet it is frequently misunderstood, dismissed, or misdiagnosed. The urge to move the legs that comes on in the evening or at night, often accompanied by uncomfortable sensations, is not just restlessness. It is a neurological condition with specific mechanisms and specific responses to treatment.

What Restless Legs Syndrome Actually Is

RLS is diagnosed based on four criteria: an urge to move the legs, usually accompanied by uncomfortable sensations; the urge worsening at rest; temporary relief from movement; and symptoms that are worse in the evening or night. The sensations people describe vary: crawling, itching, throbbing, pulling, or an electric sensation deep in the legs. Some people feel it in the arms as well.

The diagnosis is clinical, meaning there is no single test that confirms it. A doctor evaluates whether the four criteria are met and rules out other causes of similar symptoms.

A related condition called periodic limb movement disorder (PLMD) involves involuntary jerking of the legs during sleep, often without the person's awareness. Many people with RLS also have PLMD. A bed partner may notice the leg movements before the person themselves does.

Why It Happens

Dopamine Signalling

The core mechanism in RLS is a dysfunction in dopamine signalling in the brain circuits that control movement. Dopamine levels in the brain follow a daily rhythm, declining toward evening. In people with RLS, this natural decline in dopamine activity in the evening is exaggerated enough to trigger the movement urge.

This explains why dopaminergic medications, drugs that either boost dopamine or mimic its activity at receptors, are highly effective for RLS, and why symptoms reliably worsen at night.

Iron Deficiency

Iron deficiency is the most important modifiable risk factor in RLS. Iron is essential for the production and function of dopamine in the brain. Low iron stores, even without clinical anaemia, are associated with more severe RLS symptoms. In some cases, correcting iron deficiency alone substantially improves or resolves the condition.

Ferritin is the blood marker used to assess iron stores. Most conventional medicine considers ferritin above 30 nanograms per millilitre normal, but sleep specialists treating RLS typically aim for ferritin above 75 to 100, as symptoms often improve significantly at these higher levels.

Genetics

Primary RLS has a strong genetic component. It runs in families and several genetic variants have been identified that increase risk. People with a family history of RLS are significantly more likely to develop it themselves.

Secondary Causes

RLS can be triggered or worsened by pregnancy (particularly in the third trimester), kidney disease, peripheral neuropathy, and certain medications including antidepressants (particularly SSRIs and TCAs), antihistamines, antipsychotics, and some antinausea drugs. When a medication is contributing, adjusting or switching it often improves symptoms.

What Helps

Iron Supplementation

For people with low or borderline ferritin, iron supplementation is often the most impactful intervention. Oral iron supplementation with ferrous sulphate or ferrous gluconate, taken with vitamin C to improve absorption and away from food to maximise uptake, can raise ferritin to the therapeutic range over several months. The improvement in RLS symptoms is gradual but significant in many people.

Intravenous iron infusion is used in cases where oral supplementation is insufficient or poorly tolerated, and has shown particularly good results in research trials.

Magnesium

Magnesium has a role in neuromuscular function and may modulate the dopaminergic pathways involved in RLS. The evidence for magnesium specifically in RLS is less robust than for iron, but several studies show symptom improvement with supplementation, particularly in people with mild to moderate symptoms and suspected deficiency. For more on magnesium and sleep, see our article on magnesium for sleep.

Lifestyle Factors

Several behaviours consistently worsen RLS symptoms: caffeine, alcohol, smoking, and physical inactivity. Eliminating or reducing caffeine and alcohol, particularly in the evening, is often helpful. Regular moderate exercise, particularly stretching, yoga, and lower body strengthening, reduces symptom severity in a number of studies.

Reducing screen time and stimulating activity in the hours before bed helps for the same reasons it helps with any sleep problem: it reduces the overall arousal level that tends to amplify RLS symptoms.

Warm baths or leg massages before bed provide temporary relief for many people by altering peripheral circulation and sensory input to the affected limbs.

Medications

For moderate to severe RLS that does not respond adequately to lifestyle and supplementation approaches, several medication classes are effective. Alpha-2-delta calcium channel ligands, including pregabalin and gabapentin, are currently recommended first by most sleep medicine guidelines, having largely replaced older dopaminergic agents due to a better side effect profile over time.

Dopamine agonists (pramipexole, ropinirole) were historically the mainstay of RLS treatment and remain effective, but carry a risk of a phenomenon called augmentation: over time the symptoms can worsen in severity, spread to earlier in the day, or affect the arms. This has shifted prescribing practice toward the calcium channel agents for most new patients.

Opioids at low doses are sometimes used for severe, refractory cases when other treatments have failed.

RLS and Sleep

The impact on sleep is significant. The urge to move and the accompanying discomfort make it very difficult to fall asleep or remain still enough to stay asleep. People with RLS often describe lying in bed, feeling the sensations build, and eventually needing to get up and walk to get relief. This repeated pattern can cause significant sleep restriction and the associated daytime consequences of fatigue, mood changes, and cognitive difficulty.

For more on the broader picture of difficulty falling asleep and what causes it, see our article on can't sleep at night.

What This Means for Your Sleep

Restless legs syndrome is a physiological condition with real mechanisms and real treatments. The most important first step is checking ferritin, since iron deficiency is both common and correctable. Lifestyle changes to reduce caffeine, alcohol, and physical inactivity help most people to some degree. For symptoms that do not respond to these measures, current medications are highly effective. This is one sleep problem that responds well to the right treatment once identified.