The key to exam success could be as simple - and as cheap - as a glass of water.
Children who have a drink of water before sitting tests fare up to a third better, researchers have found. The reason why isn't clear, but it could be that information flows more smoothly between brain cells when they are well hydrated.
In one of the first studies of its kind, researchers from the University of East London looked at the effects of water on the performance of almost 60 boys and girls aged between seven and nine.
Half were given a 250ml glass of water to drink, and 20 minutes later, both groups were subjected to a battery of tests. One test, designed to assess visual attention and memory, involved spotting the differences between two cartoons. The water-drinkers scored 34 per cent better, the research journal Appetite reports.
They also did 23 per cent better on a more difficult version of the test and 11 per cent better on a third task that required them to cross out specified letters from a sequence. In tests designed to assess short term memory there were no differences between the two groups. Researcher Dr Caroline Edmonds said: 'Children who had a drink of water performed significantly better on a number of tasks. Our findings suggest that consuming water benefits cognitive performance in children.'