Restless legs at night are not always neurological. In a meaningful share of patients, restless-legs-type symptoms are driven by venous insufficiency — blood pooling in the leg veins — and improve substantially once the reflux is treated. If the restlessness comes with heaviness, swelling or visible veins, a venous duplex ultrasound is the fastest way to find out which kind you have.

Act fast: sudden swelling of one leg, calf pain or cramping, warmth and redness can signal a blood clot (DVT) — seek urgent medical care the same day, at an emergency department rather than a clinic. If you also have chest pain, breathlessness, or cough up blood, call emergency services now — the clot may have traveled to the lungs.

Legs that burn, ache or throb at night but feel fine in the morning usually point to a circulation cause — most often chronic venous insufficiency. Blood that pooled in the leg veins during the day irritates nerves at night, when muscle movement no longer assists drainage. A venous duplex ultrasound confirms the diagnosis; treating the reflux typically resolves the night-time burning.