The Influence of Hydration on Mood
Written By: William M. Adams, MS, ATC and Douglas J. Casa, PhD, ATC
Summary of Findings • Scientific Definition: For the purposes of this review we will define mood as the
psychological and emotional states that involve tension/anxiety, depression/dejection, anger/hostility, vigor/activity, fatigue/inertia, and confusion/bewilderment. Total mood disturbance is defined as the estimate of overall affective state that is estimated from the above six subscales.
• Hydration status has been shown to adversely affect mood with increasing levels of dehydration and has been seen with levels of dehydration as low at 1.3-‐1.5%.1–5
• Both men and women have been shown to experience disturbances in mood during both rest and exercise while mildly dehydrated. Comparatively, women seem to be affected more by dehydration than men in regards to total mood disturbance.1,2
• Total mood disturbance increases with increasing levels of dehydration and has been shown to increase with increasing impairments in cognition.7
• Dehydration can act as an additive factor to increased total mood disturbance when other factors (environmental stress, sleep loss, increased workload, and impaired nutritional status) are involved. 8,9
• Exposing soldiers to the stress of simulated combat has deleterious effects on mood, especially with increased percent of body mass loss that occurs during dehydration.10
References 1. Armstrong LE, Ganio MS, Casa DJ, et al. Mild dehydration affects mood in healthy young women. J. Nutr. 2012;142(2):382–388. 2. Ganio MS, Armstrong LE, Casa DJ, et al. Mild dehydration impairs cognitive performance and mood of men. Br. J. Nutr. 2011;106(10):1535–1543. 3. Lieberman HR, Castellani JW, Young AJ. Cognitive function and mood during acute cold stress after extended military training and recovery. Aviat Space Environ Med. 2009;80(7):629–636. 4. Gopinathan PM, Pichan G, Sharma VM. Role of Dehydration in Heat Stress-‐Induced Variations in Mental Performance. Archives of Environmental Health: An International Journal. 1988;43(1):15–17. 5. D’anci KE, Vibhakar A, Kanter JH, Mahoney CR, Taylor HA. Voluntary dehydration and cognitive performance in trained college athletes. Percept Mot Skills. 2009;109(1):251–269. 6. Ely BR, Sollanek KJ, Cheuvront SN, Lieberman HR, Kenefick RW. Hypohydration and acute thermal stress affect mood state but not cognition or dynamic postural balance. Eur. J. Appl. Physiol. 2012. 7. Lieberman HR, Bathalon GP, Falco CM, Kramer FM, Morgan CA 3rd, Niro P. Severe decrements in cognition function and mood induced by sleep loss, heat, dehydration, and undernutrition during simulated combat. Biol. Psychiatry. 2005;57(4):422–429. 8. Moore HG, Galloway JL. We Were Soldiers Once...and Young: Ia Drang -‐ the Battle That Changed the War in Vietnam. Random House Digital, Inc. 2004. 9. Meyerhoff J, Hebert M, Huhman K, Mougey E, Oleshansky M, Potegal M. Operational stress and combat stress reaction: Neurobiological approaches toward improving assessment of risk and enhancing intervention. In: Friedl K, Lieberman H, Ryan D, Bray, eds. Countermeasures for Battlefield Stressors. Baton Rouge, LA: Louisiana State University Press; 2000:27–87. 10. Lieberman HR, Tharion WJ, Shukitt-‐Hale B, Speckman KL, Tulley R. Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-‐Air-‐Land. Psychopharmacology (Berl.). 2002;164(3):250–261.
Practical Applications • Maintaining an appropriate level of hydration is essential in preventing an increase in
total mood disturbance. • Since mood and cognitive function are interrelated, maintaining a euhydrated state will
ensure optimum levels of cognitive processing and associated mood. • Since dehydration has been shown to affect mood during both rest and exercise, it is
recommended that one maintain an appropriate level of hydration throughout the day.
Looking Ahead • While evidence shows that total mood disturbance is affected by dehydration, there
have been no studies done to date looking at changes in mood with increasing levels of dehydration over time.
• Future research looking at soldiers in the military to identify the magnitude effect that hydration has on mood disturbance when soldiers experience multiple stressors at once (during a combat simulation for example).
• Additional research looking at military soldiers to see how real combat situations may affect mood, especially when they are in situations where appropriate hydration is impossible to maintain.
The Profile of Mood States (shown left in abbreviated form) is one of the valid tools that are used to assess mood. It is comprised of 65 items that asks the participant to rate their feelings based on the words provided.