RESTLESS legs is a mysterious syndrome characterised by unpleasant tickling, burning, prickling or aching sensations in the muscles. Symptoms tend to come on at night in bed, and are most common in middle-aged women.

No one knows the cause, but recently researchers have discovered that sufferers may be deficient in iron. A group of 18 patients with the syndrome had lower iron levels in their blood than 18 adults of the same age and sex without the condition, they report in Age and Ageing. Fifteen out of the 18 found their symptoms improved when they were given iron supplements.