Restless legs syndrome (RLS) is one of those conditions where the name itself is part of the problem. It sounds trivial — like fidgeting during a long meeting. The reality for the estimated 5-10% of adults who experience moderate to severe symptoms is vastly different: an overwhelming urge to move the legs that strikes primarily in the evening, disrupting sleep onset and sometimes making rest impossible for hours.

RLS is a neurological sensorimotor disorder, not a minor annoyance. And despite its prevalence, it remains widely underdiagnosed.

What It Feels Like

The core symptom is an uncomfortable sensation in the legs accompanied by an irresistible urge to move them. Patients describe it as crawling, tingling, pulling, or a deep-seated restlessness that defies easy description.

The defining diagnostic features, established by the International Restless Legs Syndrome Study Group, are: the urge to move worsens during rest, is partially relieved by movement, is worse in the evening or night, and isn’t solely attributable to another condition.

That last criterion is the tricky one, because RLS overlaps with peripheral neuropathy, nocturnal leg cramps, and anxiety-related restlessness.

The Iron Connection

The most well-established biological factor is brain iron deficiency. A patient’s blood iron levels can be within the standard reference range while brain iron concentrations are significantly reduced.

Iron is a cofactor for tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. When brain iron is low, dopamine production is impaired. Since dopaminergic activity naturally decreases in the evening, the combination creates conditions for RLS symptoms to emerge at night.

Current clinical guidelines from the Sleep Health Foundation recommend checking serum ferritin in all RLS patients and considering iron supplementation when ferritin is below 75 micrograms per litre — well above the standard laboratory lower limit of around 30.

Oral iron supplementation works slowly and unpredictably. Intravenous iron infusion produces faster, more reliable results but requires specialist referral and is underused.

The Dopamine Agonist Problem

For decades, dopamine agonists (pramipexole, ropinirole) were first-line treatment for RLS. They’re effective short-term. The problem is augmentation — a phenomenon where long-term use paradoxically worsens symptoms. The urge to move begins earlier in the day, spreads to the arms, and becomes more intense. Higher doses accelerate the worsening.

Augmentation rates range from 30-70% of patients over five years. This has driven a major shift in treatment guidelines. The American Academy of Sleep Medicine now recommends alpha-2-delta ligands (gabapentin, pregabalin) as first-line pharmacotherapy ahead of dopamine agonists. These work through a different mechanism and don’t carry augmentation risk, though sedation and weight gain are common side effects.

Why Diagnosis Takes So Long

The average time from symptom onset to RLS diagnosis is estimated at 10-15 years internationally.

Patients don’t raise it. Many assume the symptoms are normal or trivial. The sensation is hard to describe, and patients worry about sounding vague.

GPs don’t screen for it. When a patient reports poor sleep, the typical workup covers anaemia, thyroid function, and depression. The specific question — “Do you get an uncomfortable urge to move your legs when resting?” — is rarely asked.

Mimics cause confusion. Nocturnal leg cramps, peripheral neuropathy, and anxiety-related fidgeting can all look like RLS from a brief clinical description. Distinguishing them requires detailed symptom history that may not be collected in a ten-minute appointment.

What You Can Do

If you suspect RLS, practical steps worth taking:

Track the pattern. Log when symptoms start, what you’re doing, whether movement helps, and how they affect sleep. This information is enormously helpful for clinical evaluation.

Get ferritin checked. Discuss the result in the context of RLS-specific thresholds — below 75, not the lab’s standard reference range.

Ask for a sleep medicine referral. Complex cases benefit from specialist assessment. Sleep physicians are familiar with current treatment algorithms and can navigate the dopamine agonist versus alpha-2-delta ligand decision.

Be cautious with dopamine agonists. If prescribed pramipexole or ropinirole, ask about augmentation risk and what the monitoring plan will be.

RLS is common, treatable, and far more disabling than its name suggests. Getting the right diagnosis requires patients and clinicians to take the symptoms seriously enough to investigate properly.