Remain thirsty if you want to do better on quiz shows

If you want to be a millionaire by getting the questions right in a television game show, then avoid sipping glasses of water nervously. Psychologists believe that drinking at the wrong time can damage your mental performance.

If you want to be a millionaire by getting the questions right in a television game show, then avoid sipping glasses of water nervously. Psychologists believe that drinking at the wrong time can damage your mental performance.

A study of the effects of sipping water while trying to perform the rigorous intellectual tasks required by the Chris Tarrants of the world shows just how important an effect drinking can have. Peter Rogers, an experimental psychologist at the University of Bristol, asked 60 volunteers to rate how thirsty they felt. Some were given a cupful of tap water to drink, while others were not allowed to drink anything.

Dr Rogers then asked them to do some mental tests. Not surprisingly, those that were thirsty and had something to drink performed about 10 per cent better than the volunteers who were not allowed to drink.

However, when those who were not thirsty drank water their performance tailed off, with some dropping by 15 per cent compared with non-thirsty people who refrained from drinking. Drinking too much water might affect a person's ability to drive or perform intellectually demanding tasks, Dr Rogers said in a paper published in the journal Appetite.

One explanation could be that a cold drink diverts blood from the brain to the gut in the same way as a heavy meal causes drowsiness. "We like our drinks hot or cold. The body has to divert resources to deal with the local cooling effect in the gut," Dr Rogers told the New Scientist magazine.