You're describing what's known as restless legs syndrome, a common condition that affects up to one in 12 of the population. For most people, it's mild and improves with simple measures, although some need more intensive medical therapy.

There are four characteristic features in restless legs syndrome. These include:

• An irritating, non-painful sensation in your legs that gives you an overwhelming urge to move them. Occasionally, this sensation also occurs in the arms.
• Symptoms occur (or are worse) when you're resting. They improve when you move your legs around.
• Symptoms are worse from evening onwards, especially when you lie down, but you don't have to be in bed or going to sleep.
• Little movements of the toes, feet or legs may be visible when you rest, which may look like nervous fidgeting.

You may also find you have repeated jerky leg movements while you're asleep that can wake you up or disturb your partner. If this is persistent, it's hardly surprising you feel tired during the day.

The cause of restless legs syndrome isn't yet known, but an inherited tendency does seem to be a contributing factor in many cases. It often becomes more of a problem in older age, but can also occur in young people where it's often misdiagnosed as growing pains.

Many women develop the problem in the last term of pregnancy yet it usually disappears after delivery. Anaemia and iron deficiency may also be linked, while restless legs may be a sign of more serious chronic conditions such as diabetes, kidney failure, Parkinson's disease and rheumatoid arthritis. Some drugs, such as antidepressants, can make the condition worse.

However, simple lifestyle changes can alleviate your symptoms. Caffeine and alcohol can aggravate the condition so cut out caffeine-containing drinks (such as coffee, tea, hot chocolate and soft drinks) and any other product that has caffeine as an ingredient, and avoid alcohol, at least until you see if your symptoms improve.

Another common trigger is a lack of sleep (it's a bit of a vicious circle, I'm afraid). Follow good sleep habits such as a regular bedtime at a reasonable hour, a cool, comfortable and quiet bedroom, and regular moderate exercise during the day (several hours before you go to bed). You should also start and end the day with a routine of gentle exercise to stretch out the muscles.

If these simple steps don't help, you should see your doctor. They will want to rule out any more serious underlying causes, and then may consider treatment with one of several possible medicines, which might help.

This article was last medically reviewed by Dr Trisha Macnair in June 2008