The Hydration Equation: Update on Water Balance and Cognitive Performance

ACSMs Health Fit J. 2013 Nov;17(6):21-28. doi: 10.1249/FIT.0b013e3182a9570f.


To become aware of the most practical measures of hydration status.To describe sources of water input and output and the basics of water balance.To understand how hydration status may impact daily cognitive performance.

Condensed version and bottom line: Water is a crucial nutrient and euhydration is necessary for optimal daily functioning. Water balance is precisely regulated within the body and many methods exist for assessing hydration status. Cognitive performance measures an individual's attentiveness, critical thinking skills, and memory. Traditionally a 2% or more body water deficit was thought to produce cognitive performance decrements; however, recent literature suggests that even mild dehydration - a body water loss of 1-2% - can impair cognitive performance. Counseling clients about their health and wellbeing should include conveying the importance of water for normal body functioning, as well as its effects on physical and cognitive performance.

Keywords: cognitive function; fluid; hydration assessment; mood; water intake.