The feeling is worse when you're sitting down or in bed, can disturb your sleep and be accompanied by a maddening ‘creeping’ or ‘crawling’ sensation.
Although the cause of RLS is unknown, there's evidence to suggest that it may be linked to the production of the brain chemical dopamine, which is needed for normal movement and muscle control.
Around one in four people with RLS have an iron deficiency and, because iron is needed for dopamine metabolism, experts have suggested people with RLS may not metabolise iron normally, triggering symptoms.
20 per cent of pregnant women suffer from RLS, though it occurs mostly in the last trimester, and usually goes away after giving birth. As a result, experts say this may indicate a hormonal influence.
Other than an intense urge to move your limbs, RLS can also cause tingling, burning, itching, pins and needles, creeping and crawling sensations or cramping symptoms. Between 30 and 50 per cent of sufferers say RLS is painful.
Symptoms are known to be much worse in the evenings and at night, and can disrupt sleep.
The International Restless Legs Syndrome Study Group’s diagnostic criteria lists five main symptoms that must be fulfilled in order to be diagnosed with RLS. These include: a frequent urge to move the legs; periods of inactivity making symptoms worse; movement relieving symptoms; symptoms being worse at night; and symptoms not attributable to different health or behaviour conditions.
Before a diagnosis is made you may also need blood tests to rule out other potential causes for your symptoms, such as iron deficiency.
Who gets RLS?
RLS is estimated to affect around five per cent of the population, though this figure rises to 10 per cent in the over 65s. It is also twice as common among women than men. Explanations for this include hormonal influences, and iron and folate deficiencies often found in pregnant women.
Although RLS is far less common in children, 70 per of children who do get it will have a parent with the condition, suggesting there's a genetic element to the disease.
Underlying health conditions can increase your risk of getting RLS. Up to a quarter of patients on kidney dialysis have RSL. Diabetes is also associated with RLS, as it can lead to nerve damage in the feet and legs.
Some prescription drugs - particularly antidepressants - may cause RLS symptoms or make them worse. Studies have found common antidepressants including, sertraline, fluoxetine and citalopram directly caused RLS in nine per cent of patients. The drug mirtazapine was found to affect up to 28 per cent of patients.
Your doctor can address underlying, causes such as iron deficiency or prescription drug side effects, by prescribing iron supplements or changing your medication.
Lifestyle changes such as avoiding caffeine and alcohol in the evenings, giving up smoking and taking regular exercise may also help.
Drugs that increase the level of dopamine in the brain are sometimes prescribed to reduce symptoms and should be taken at night to get the best effect. Other drugs called pregabalin or gabapentin can also be prescribed, while benzodiazepines and Z drugs (e.g. zopiclone) can be used to help improve quality of sleep and relax the body.
Red vine leaf extract is a natural supplement made from the grape vine, and is often used to help with circulation problems. Not only can this improve symptoms of varicose veins, it also ease the aches and discomfort of RLS. Other supplements to try include: iron, magnesium, folic acid, and vitamin B12.
Although exercise relieves symptoms, the effect is temporary and they will eventually return during rest periods.
Positional release manipulation, an osteopathic technique where you hold your limbs and body in different positions, may relieve the pain of RLS.