Even mild dehydration can impair a person’s ability to think, according to a study from Swansea University, UK. More than 100 people were subjected to hot temperatures for four hours with or without access to water. Changes in body mass, urine output, body temperature, and thirst were monitored. Memory, focused attention, mood, and perceived difficulty in doing tasks were measured on three occasions. Results showed that even mild dehydration, equivalent to losing 1% of body mass, impaired memory and focused attention. In the short term, thirst was associated with poorer memory. After an hour and a half, thirst also was linked to a higher incidence of depression and anxiety. Those participants who drank water during the experiment managed, both physically and mentally, far better. The level of dehydration noted in this study easily develops during everyday living. The researchers conclude that this is the first time mild dehydration has been linked to impaired cognitive functioning.
Elizabeth Somer, M.A.,R.D.
Benton D, Jenkins K, Watkins H, et al: Minor degree of hypohydration adversely influences cognition. American Journal of Clinical Nutrition 2016;104:603-612.