New research from Tufts University looks at how mild dehydration can affect mood and mental performance. The results of this study pose an interesting question: what happens when you don’t get enough water in your day? It turns out that mood and performance could suffer as a result of dehydration.
The Tufts researchers focused on mental performance—how dehydration impacts the mood and cognition of young athletes. They took student athletes and formed two groups, the dehydrated group and the control group, and tested them after exercise. In examining mental performance they discovered that dehydration was associated with negative mood and impaired attention.
According to the authors of the study, the mild dehydration witnessed by the student athletes could be similar to the mild dehydration experienced by people who don’t drink enough water.
The research was supported in part by the U.S. Agricultural Research Service (ARS).
Percept Mot Skills. 2009 Aug;109(1):251-69.
Voluntary dehydration and cognitive performance in trained college athletes.
D’Anci KE, Vibhakar A, Kanter JH, Mahoney CR, Taylor HA.
Tufts University Department of Psychology, Jean Mayer USDA Human Nutrition Research Center on Aging, Medford, MA 02155, USA.
Cognitive and mood decrements resulting from mild dehydration and glucose consumption were studied. Men and women (total N = 54; M age = 19.8 yr., SD = 1.2) were recruited from college athletic teams. Euhydration or dehydration was achieved by athletes completing team practices with or without water replacement. Dehydration was associated with higher thirst and negative mood ratings as well as better Digit Span performance. Participants showed better Vigilance Attention with euhydration. Hydration status and athlete’s sex interacted with performance on Choice Reaction Time and Vigilance Attention. In a second study, half of the athletes received glucose prior to cognitive testing. Results for negative mood and thirst ratings were similar, but for cognitive performance the results were mixed. Effects of glucose on cognition were independent of dehydration.
Nutrition in Clinical Care. Dec. 1, 2005 8(4):163-6.
Hydration status and cognitive performance in young adults.
D’Anci K.E. TUFTS/HNRCA
Technical Abstract: Adequate hydration levels are important for both mental and physical functioning. Research conducted in young adults suggests that mild levels of dehydration (2%-4%) can negatively influence cognitive performance in a variety of tasks, but these data are inconsistent. Dehydration may be relatively common in young adults, especially following athletic events, and hypohydration may persist for several hours following exercise. In healthy young adults, symptoms of confusion, cognitive impairment, and fatigue may be indicative of mild dehydration brought about by exposure to heat or by physical activity.
J Am Coll Nutr. 2007 Oct;26(5 Suppl):549S-554S.
Dehydration and cognitive performance.
Grandjean AC, Grandjean NR.
The Center for Human Nutrition, Room 1024 505 Durham Research Plaza, Omaha, Nebraska 68105, USA.
Human neuropsychology investigates brain-behavior relationships, using objective tools (neurological tests) to tie the biological and behavior aspects together. The use of neuropsychological assessment tools in assessing potential effects of dehydration is a natural progression of the scientific pursuit to understand the physical and mental ramifications of dehydration. It has long been known that dehydration negatively affects physical performance. Examining the effects of hydration status on cognitive function is a relatively new area of research, resulting in part from our increased understanding of hydration’s impact on physical performance and advances in the discipline of cognitive neuropsychology. The available research in this area, albeit sparse, indicates that decrements in physical, visuomotor, psychomotor, and cognitive performance can occur when 2% or more of body weight is lost due to water restriction, heat, and/or physical exertion. Additional research is needed, especially studies designed to reduce, if not remove, the limitations of studies conducted to date.