To ask the Secretary of State for Health what assessment his Department has made of the effect of mild dehydration on mental performance in (a) children and (b) adults. (151141)

The Government have not assessed the effect of mild dehydration on mental performance.

The Government do, however, advise that 6-8 glasses (about 1.2 litres) of water, or other fluids, should be consumed every day to prevent dehydration. This is based on physiological studies and this amount should be increased when the weather is warm or when exercising.