In fact the suggestion
that adults need to drink more liquid has been questioned. Valtin
(2002) reviewed the influence of drinking more water on a range of
medical parameters. He concluded that ‘‘no scientific studies were
found in support’’ of the suggestion that we should drink eight
glasses of water a day; at least in healthy individuals in temperate
climates living a sedentary lifestyle. The literature on the effect of
dehydration on cognition in adults can be seen as consistent with
this view