Restless legs at night: causes, red flags and when to get it checked

Restless legs syndrome is a neurological sensory-motor disorder linked to how the brain handles iron and dopamine. Symptoms follow a circadian rhythm, peaking late in the evening. It is common, affecting a sizeable minority of adults and more women than men, and is often under-recognised.

• Primary (idiopathic) restless legs, often running in families, starting at any age.

• Iron deficiency, with or without anaemia, and heavy periods or poor diet.

• Pregnancy, particularly in the third trimester, usually settling after birth.

• Medicines: antidepressants (SSRIs and others), antihistamines, antipsychotics, metoclopramide and some cold remedies.

• Caffeine, alcohol, nicotine and sleep deprivation.

• Chronic kidney disease, diabetes and peripheral neuropathy.

• Underactive thyroid, rheumatoid arthritis and Parkinson disease.

• Spinal cord problems and venous insufficiency, which can mimic it.

Symptoms starting abruptly, weakness or numbness in the legs, symptoms in only one leg, leg swelling, severe tiredness or pallor, symptoms in a young child, neurological features such as tremor, and symptoms that rapidly worsen on dopamine-type treatment (augmentation) warrant specialist review.

• Call 999: sudden leg weakness with loss of bladder or bowel control, or with chest pain or breathlessness.

• Same-day GP: restless legs with a swollen, painful calf, or sudden severe leg pain.

• GP within weeks: symptoms most nights disrupting sleep.

• Routine: occasional mild symptoms after caffeine or a poor night.

The doctor asks about the urge to move, timing, relief with movement, effects on sleep, family history, pregnancy, caffeine, alcohol, medicines, diet, periods, kidney and thyroid conditions. They examine the legs, pulses, reflexes, sensation and look for signs of anaemia or neuropathy.

• Ferritin and full blood count: low iron stores are important, with treatment often aimed at ferritin above a threshold your clinician will advise.

• Kidney function, glucose or HbA1c, thyroid function, B12 and folate.

• Sleep study: if periodic limb movements or sleep apnoea are suspected.

• Nerve conduction studies: if neuropathy is suspected.

• Review of all medicines and substances.

Cut caffeine, alcohol and nicotine, keep regular sleep times, take moderate exercise earlier in the day, and try a warm bath, stretching or massage before bed. Review medicines with a pharmacist or GP rather than stopping them. Iron replacement is used if stores are low. Prescription options include certain nerve-pain medicines; dopamine drugs are used cautiously because of augmentation.

The NHS route is a GP, then neurology or sleep medicine if needed. Private neurology and sleep clinics offer direct access to assessment and testing.