title: Effect of water deprivation on cognitive-motor performance in healthy men and women.
abstract: Whether mental performance is affected by slowly progressive moderate dehydration induced by water deprivation has not been examined previously. Therefore, objective and subjective cognitive-motor function was examined in 16 volunteers (8 females, 8 males, mean age: 26 yr) twice, once after 24 h of water deprivation and once during normal water intake (randomized cross-over design; 7-day interval). Water deprivation resulted in a 2.6% decrease in body weight. Neither cognitive-motor function estimated by a paced auditory serial addition task, an adaptive 5-choice reaction time test, a manual tracking test, and a Stroop word-color conflict test nor neurophysiological function assessed by auditory event-related potentials P300 (oddball paradigm) differed (P > 0.1) between the water deprivation and the control study. However, subjective ratings of mental performance changed significantly toward increased tiredness (+1.0 points) and reduced alertness (-0.9 points on a 5-point scale; both: P < 0.05), and higher levels of perceived effort (+27 mm) and concentration (+28 mm on a 100-mm scale; both: P < 0.05) necessary for test accomplishment during dehydration. Several reaction time-based responses revealed significant interactions between gender and dehydration, with prolonged reaction time in women but shortened in men after water deprivation (Stroop word-color conflict test, reaction time in women: +26 ms, in men: -36 ms, P < 0.01; paced auditory serial addition task, reaction time in women +58 ms, in men -31 ms, P = 0.05). In conclusion, cognitive-motor function is preserved during water deprivation in young humans up to a moderate dehydration level of 2.6% of body weight. Sexual dimorphism for reaction time-based performance is present. Increased subjective task-related effort suggests that healthy volunteers exhibit cognitive compensating mechanisms for increased tiredness and reduced alertness during slowly progressive moderate dehydration.
authors.affiliation: Division of Endocrinology, Diabetes & Clinical Nutrition, Department of Internal Medicine, University Hospital, CH 4031 Basel, Switzerland.
authors.forename: Gabor
authors.initials: G
authors.lastname: Szinnai
authors.forename: Hartmut
authors.initials: H
authors.lastname: Schachinger
authors.forename: Maurice J
authors.initials: MJ
authors.lastname: Arnaud
authors.forename: Lilly
authors.initials: L
authors.lastname: Linder
authors.forename: Ulrich
authors.initials: U
authors.lastname: Keller
mesh_terms: D000328:Adult; D001288:Attention; D001826:Body Fluids / Q000378:metabolism; D003071:Cognition / Q000502:physiology*; D018592:Cross-Over Studies; D003681:Dehydration / Q000209:etiology / Q000503:physiopathology / Q000523:psychology; D018913:Event-Related Potentials, P300; D005072:Evoked Potentials, Auditory; D005221:Fatigue / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009318:Natriuresis; D009483:Neuropsychological Tests; D009994:Osmolar Concentration; D012016:Reference Values; D012727:Sex Characteristics; D012964:Sodium / Q000097:blood; D013894:Thirst; D014868:Water Deprivation / Q000502:physiology*
chemical_list: D012964:Sodium