Healthy hydration for cognition and mood state

Our brain is made of 75% water. It seems therefore logical that dehydration may have an impact on cognitive functions and mood.

Several studies, performed in healthy persons, looked at the effects of induced dehydration on cognitive performance and motor function: fatigue, mood, choice reaction time, short- and long-term memory, attention, arithmetics… It appears that a 2% dehydration is sufficient to impair functions and performances.1,2 Some studies have suggested that adverse effects may even be present at 1% dehydration.3,4

Young children and adolescents, in particular, may be at risk of impaired cognitive function (concentration, alertness and short-term memory) due to insufficient hydration.5,6


  1. Institute of Medicine (IOM). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington, DC: National Academies Press,2004.
  2. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary reference values for water. EFSA Journal. 2010; 8:1459-507. doi:10.2903/j.efsa.2010.1459. Available online:
  3. Gopinathan PM, Pichan G, Sharma VM. Role of dehydration in heat stress-induced variations in mental performance. Arch Env Health. 1998;43:15–7.
  4. Lieberman HR. Hydration and Cognition: A Critical Review and Recommendations for Future Research. J Am CollNutr. 2007;26:S555-61.
  5. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to water and maintenance of normal physical and cognitive function (ID 1102, 1209, 1294, 1331), maintenance of normal thermoregulation (ID 1208) and “basic requirement of all living things” (ID 1207) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal. 2011;9:2075-91. doi:10.2903/j.efsa.2011.2075. Available online:
  6. D'Anci KE, Constant F, Rosenberg IH. Hydration and cognitive function in children. Nutr Rev. 2006;64:457-64.
A young woman sitting a table working

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