Acceso usuarios
Castle, Reino Unido
Introduction: The study of small changes in hydration status has been largely ignored.
Objective: To see if drinking water, when mildly hypohydrated (a loss of 0.7% of body mass), helps to maintain cognitive functioning and mood and to explore underlying mechanisms.
Method: 118 (61 male) young adults were exposed to a temperature of 30ºC for four hours and either did or did not drink two 150ml glasses of water during that time. On three occasions, once at baseline and once after each drink, they completed cognitive tests and rated their thirst, energy and task difficulty. Changes in body temperature and perspiration were monitored throughout and considered, along with thirst and ratings of difficulty, as potential mediators. Individual differences in habitual water consumption and baseline urine osmolality were also considered.
Results: Participants had better memory, attention and energy levels if they had drunk water but this depended upon habitual water consumption and baseline osmolality. Thirst mediated the effect of drinking on memory and energy levels, whereas perspiration mediated the effects on attention. Neither a change in temperature, nor gender, affected the results. Although participants found the tasks easier if they had drunk, these ratings of task difficulty were not found to mediate the effects on cognition.
Conclusions: Drinking water when hypohydrated improves cognition although the mechanisms involved vary with cognitive domain.
