Water may zap brain power - warn scientists

by JAMES CHAPMAN, Daily Mail

IT could have been the moment Steve Devlin lost the chance to win Who Wants To Be A Millionaire?

With the £1million question hanging on his reply, the 53-year-old contestant reached over for a glass of water - and made possibly a crucial mistake.

In gulping it down at a moment of stress, Mr Devlin was zapping his brain power, according to a team of scientists who have just researched the subject.

Their findings may explain why Mr Devlin failed to answer the crucial question on Saturday's show - and why countless others may perform worse than expected in tests and exams.

The scientists believe it could be the temperature of the water which impairs mental performance.

'We like our drinks hot or cold,' said psychologist Professor Peter Rogers, who led the research. 'The body has to divert resources to deal with the local cooling effect in the gut.'

To test the theory, Prof Rogers and his team at the University of Bristol put 60 volunteers through a two-hour test in which they had to press buttons in response to prompts on a computer screen.

Before starting, the volunteers were asked how thirsty they felt - and either drank nothing or had a 330ml cup of tap water which had been chilled to 10C.

People who were thirsty at the beginning of the trial and took a drink performed ten per cent better than those who drank nothing.

But the most marked difference came in the performance of those who were not thirsty to start with. After having a drink during the tests, their scores dropped by 15 per cent - with the effect lasting up to 50 minutes.

Prof Rogers believes the findings, published today in the New Scientist and the medical journal Appetite, show that a cool drink might not be the best thing to have before undertaking an intellectually demanding task.

It could even impair people's driving ability, he says.

'These results show that mental performance is affected by water intake,' he said.

'When thirst was low, the impact of water intake was detrimental, showing that mental performance can be very sensitive to physiological perturbation.'

Scientists already know that eating food can have an impact on mental performance. Substantial physiological resources are deployed by the body in digesting a meal and storing the rush of nutrients that follows in the blood.

This accounts for the 'post-lunch dip' experienced by many people.

Separate research by Prof Rogers also suggests that a cup of coffee or tea at breakfast-time does not improve mental agility, as is popularly believed.

Instead, it simply reverts caffeine drinkers to the level of alertness of non-drinkers, he says.

Dr Nick Neave, lecturer in psychology at the University of Northumbria, said: 'If your performance is changing by 15 per cent, that's quite a big effect.'

All of which will be of little comfort to Steve Devlin, who thought he knew that former U.S. president Theodore Roosevelt had stood for the Bull Moose party in 1912 before host Chris Tarrant planted a seed of doubt in his mind.

But the unemployed Belfast man at least had the thought of the £500,000 he did win to carry him home.

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