The impact of asking children to drink water during their school days, and its possible influence on school
performance, has been little considered using intervention studies. Therefore in the afternoon the
cognitive functioning of 40 children (mean of 8 years and 7 months) was assessed twice, once after
drinking 300 ml of water and on another day when no water was provided. Memory was assessed by the
recall of 15 previously presented objects. Recall was significantly better on the occasions when water had
been consumed. The ability to sustain attention was measured by asking the child to respond to a light
that followed an auditory warning after a delay of either 3 or 12 s. The ability to sustain attention was not
significantly influenced by whether water had been drunk