Fonctions cognitives et hydratation

A clinical association exists between severe dehydration and cognitive performance. Army physiologists attempt to optimize physical and cognitive performances of personnel in hostile environments. Using rapid and severe water loss induced either by intense exercise and/or heat stress, initial studies have suggested alteration in short term memory and cognitive function related to vision. More recent studies have not all confirmed these data. Some studies argue that water loss is not responsible for the observations made, and studies compensating water losses have failed to prevent the symptoms. Studies in children suggest that drinking extra water helps cognitive performance. These data however rely on a small number of children. In older adults (mean age around 60 years) data are not strong enough to support a relationship between mild dehydration and cognitive function. Data in frail elderly and demented people are lacking. Methodological weaknesses in these studies prevent from concluding on a relationship between mild dehydration and cognitive performance.