title: Mild dehydration impairs cognitive performance and mood of men.
abstract: The present study assessed the effects of mild dehydration on cognitive performance and mood of young males. A total of twenty-six men (age 20·0 (sd 0·3) years) participated in three randomised, single-blind, repeated-measures trials: exercise-induced dehydration plus a diuretic (DD; 40 mg furosemide); exercise-induced dehydration plus placebo containing no diuretic (DN); exercise while maintaining euhydration plus placebo (EU; control condition). Each trial included three 40 min treadmill walks at 5·6 km/h, 5 % grade in a 27·7°C environment. A comprehensive computerised six-task cognitive test battery, the profile of mood states questionnaire and the symptom questionnaire (headache, concentration and task difficulty) were administered during each trial. Paired t tests compared the DD and DN trials resulting in >1 % body mass loss (mean 1·59 (sd 0·42) %) with the volunteer's EU trial (0·01 (sd 0·03) %). Dehydration degraded specific aspects of cognitive performance: errors increased on visual vigilance (P = 0·048) and visual working memory response latency slowed (P = 0·021). Fatigue and tension/anxiety increased due to dehydration at rest (P = 0·040 and 0·029) and fatigue during exercise (P = 0·026). Plasma osmolality increased due to dehydration (P < 0·001) but resting gastrointestinal temperature was not altered (P = 0·238). In conclusion, mild dehydration without hyperthermia in men induced adverse changes in vigilance and working memory, and increased tension/anxiety and fatigue.
authors: Texas Health Presbyterian Hospital, Institute for Exercise and Environmental Medicine, Dallas, TX 75231, USA.
authors: Matthew S
authors: MS
authors: Ganio
authors: Lawrence E
authors: LE
authors: Armstrong
authors: Douglas J
authors: DJ
authors: Casa
authors: Brendon P
authors: BP
authors: McDermott
authors: Elaine C
authors: EC
authors: Lee
authors: Linda M
authors: LM
authors: Yamamoto
authors: Stefania
authors: S
authors: Marzano
authors: Rebecca M
authors: RM
authors: Lopez
authors: Liliana
authors: L
authors: Jimenez
authors: Laurent
authors: L
authors: Le Bellego
authors: Emmanuel
authors: E
authors: Chevillotte
authors: Harris R
authors: HR
authors: Lieberman
mesh_terms: D000328:Adult; D000339:Affect; D003071:Cognition; D018592:Cross-Over Studies; D003681:Dehydration; D015444:Exercise; D006801:Humans; D008297:Male; D010919:Placebos; D016037:Single-Blind Method; D013647:Task Performance and Analysis
chemical_list: D010919:Placebos