Restless legs syndrome typically causes an overwhelming urge to move your legs and an uncomfortable sensation in your legs.

The sensation may also affect your arms, chest and face.

It's been described as:

• tingling, burning, itching or throbbing
• a "creepy-crawly" feeling
• feeling like fizzy water is inside the blood vessels in the legs
• a painful cramping sensation in the legs, particularly in the calves

These unpleasant sensations can range from mild to unbearable, and are usually worse in the evening and during the night. They can often be relieved by moving or rubbing your legs.

Some people experience symptoms occasionally, while others have them every day.

You may find it difficult to sit for long periods of time (for example, on a long train journey).

Periodic limb movements (PLM)

More than 80% of people with restless legs syndrome also have periodic limb movements (PLM).

If you have PLM, your leg will jerk or twitch uncontrollably, usually at night while you're asleep.

The movements are brief and repetitive, and usually occur every 20 to 40 seconds.

PLM can be severe enough to wake up both you and your partner. The involuntary leg movements can also occur when you're awake and resting.

In many cases, the exact cause of restless legs syndrome is unknown.

When no cause can be found, it's known as idiopathic or primary restless legs syndrome.

Research has identified specific genes related to restless legs syndrome, and it can run in families. In these cases, symptoms usually occur before the age of 40.

Dopamine

There's evidence to suggest restless legs syndrome is related to a problem with part of the brain called the basal ganglia.

The basal ganglia uses a chemical (neurotransmitter) called dopamine to help control muscle activity and movement.

Dopamine acts as a messenger between the brain and nervous system to help the brain regulate and co-ordinate movement.

If nerve cells become damaged, the amount of dopamine in the brain is reduced, which causes muscle spasms and involuntary movements.

Dopamine levels naturally fall towards the end of the day, which may explain why the symptoms of restless legs syndrome are often worse in the evening and during the night.

Underlying health condition

Restless legs syndrome can sometimes occur as a complication of another health condition, or it can be the result of another health-related factor.

This is known as secondary restless legs syndrome.

You can develop secondary restless legs syndrome if you:

• have iron deficiency anaemia (low levels of iron in the blood can lead to a fall in dopamine, triggering restless legs syndrome)
• have a long-term health condition (such as chronic kidney disease, diabetes, Parkinson's disease, rheumatoid arthritis, an underactive thyroid, or fibromyalgia)
• are pregnant (particularly from week 27 until birth; in most cases the symptoms disappear within 4 weeks of giving birth)

Triggers

There are a number of triggers that don't cause restless legs syndrome, but can make symptoms worse.

These include medications such as:

• antidepressants
• some antipsychotics
• lithium (used in the treatment of bipolar disorder)
• antihistamines

Other possible triggers include:

• excessive caffeine or alcohol
• smoking
• being overweight or obese
• stress

There's no single test for diagnosing restless legs syndrome.

A diagnosis will be based on your symptoms, medical history and family history, a physical examination, and test results.

Your GP should be able to diagnose restless legs syndrome, but they may refer you to a neurologist if there's any uncertainty.

There are 4 main criteria your GP or specialist will look for to confirm a diagnosis.

These are:

• an overwhelming urge to move your legs, usually with an uncomfortable sensation, such as itching or tingling
• your symptoms occur or get worse when you're resting or inactive
• your symptoms are relieved by moving your legs or stretching them
• your symptoms are worse during the evening or at night

Assessing your symptoms

Your GP or specialist will ask you about the pattern of your symptoms to help assess their severity.

For example, they may ask you:

• how often you have symptoms
• how unpleasant you find your symptoms
• whether your symptoms cause significant distress
• whether your sleep is disrupted, making you tired during the day

Keeping a sleep diary may help your doctor assess your symptoms.

You can use the diary to record your daily sleeping habits, such as the time you go to bed, how long it takes you to fall asleep, how often you wake during the night, and episodes of tiredness during the day.

Mild symptoms of restless legs syndrome can usually be treated by making lifestyle changes.

For example:

• establishing a regular sleeping pattern
• avoiding stimulants, such as caffeine, alcohol or tobacco, in the evening

If your symptoms are more severe, you may need medication to bring them under control.

Blood tests

Your GP may refer you for blood tests to confirm or rule out possible underlying causes of restless legs syndrome. 

For example, you may have blood tests to rule out conditions such as anaemia, diabetes and kidney function problems.

It's particularly important to find out the levels of iron in your blood because low iron levels can sometimes cause secondary restless legs syndrome.

Low iron levels can be treated with iron tablets.

Sleep tests

If you have restless legs syndrome and your sleep is being severely disrupted, you may be referred to a sleep clinic.

Occasionally, polysomnography may be recommended. This is a test that measures your breathing rate, brain waves and heartbeat throughout the course of a night.

The results of a polysomnography test will confirm whether you have periodic limb movements in sleep (PLMS).

Mild restless legs syndrome that isn't linked to an underlying health condition can be managed with just a few lifestyle changes.

If symptoms are more severe, medication may be needed.

Restless legs syndrome caused by an underlying health condition can often be cured by treating that condition.

For example, iron deficiency anaemia can be treated by taking iron supplements.

If it's associated with pregnancy, it usually disappears on its own within 4 weeks of the birth.

Lifestyle changes

A number of lifestyle changes may be enough to ease the symptoms of restless legs syndrome.

These include:

• avoiding stimulants in the evening (such as caffeine, tobacco and alcohol)
• not smoking (read more about quitting smoking)
• regular daily exercise (but avoid exercising close to bedtime)
• good sleep habits (tips to beat insomnia include going to bed and getting up at the same time every day, not napping during the day, taking time to relax before going to bed, and avoiding caffeine close to bedtime)
• avoiding medicines that trigger the symptoms or make them worse (if you think medication is causing your symptoms, continue to take it and make an appointment to see your GP)

During an episode of restless legs syndrome, the following measures may help relieve your symptoms:

• massaging your legs
• taking a hot bath in the evening
• applying a hot compress to your leg muscles
• doing activities that distract your mind, such as reading or watching television
• relaxation exercises, such as yoga or tai chi
• walking and stretching

Medicine

Dopamine agonists

Dopamine agonists may be recommended if you're experiencing frequent symptoms of restless legs syndrome.

They work by increasing dopamine levels, which are often low.

Dopamine agonists that may be recommended include:

• ropinirole
• pramipexole
• rotigotine skin patch

These medications can occasionally make you feel sleepy, so you should be cautious when driving or using tools or machinery after taking them.

Other possible side effects can include nausea or vomiting and dizziness.

Impulse control disorder (ICD) is a less common side effect sometimes associated with dopamine agonists.

People with ICD are unable to resist the urge to do something harmful to themselves or others.

For example, this could be an addiction to alcohol, drugs, gambling, shopping or sex (hypersexuality).

But the urges associated with ICD will subside once treatment with the dopamine agonist is stopped.

Painkillers

A mild opiate-based painkiller, such as codeine, may be prescribed to relieve pain associated with restless legs syndrome.

Gabapentin and pregabalin are also sometimes prescribed to help relieve painful symptoms of restless legs syndrome.

Side effects of these medications include dizziness, tiredness and headaches.

Medicines for aiding sleep

If restless legs syndrome is badly disrupting your sleep, a short-term course of medicine may be recommended to help you sleep.

These types of medicines are known as hypnotics, and include zopiclone and zolpidem.

Hypnotics are usually only recommended for short-term use (typically no longer than a week).

You may find you still feel sleepy or "hungover" the morning after taking your medicine.