title: Mild hypohydration increases the frequency of driver errors during a prolonged, monotonous driving task.
abstract: The aim of the present study was to examine the effect of mild hypohydration on performance during a prolonged, monotonous driving task.
  
  
  METHODS
  Eleven healthy males (age 22±4y) were instructed to consume a volume of fluid in line with published guidelines (HYD trial) or 25% of this intake (FR trial) in a crossover manner. Participants came to the laboratory the following morning after an overnight fast. One hour following a standard breakfast, a 120min driving simulation task began. Driver errors, including instances of lane drifting or late breaking, EEG and heart rate were recorded throughout the driving task
  
  
  RESULTS
  Pre-trial body mass (P=0.692), urine osmolality (P=0.838) and serum osmolality (P=0.574) were the same on both trials. FR resulted in a 1.1±0.7% reduction in body mass, compared to -0.1±0.6% in the HYD trial (P=0.002). Urine and serum osmolality were both increased following FR (P<0.05). There was a progressive increase in the total number of driver errors observed during both the HYD and FR trials, but significantly more incidents were recorded throughout the FR trial (HYD 47±44, FR 101±84; ES=0.81; P=0.006) CONCLUSIONS: The results of the present study suggest that mild hypohydration, produced a significant increase in minor driving errors during a prolonged, monotonous drive, compared to that observed while performing the same task in a hydrated condition. The magnitude of decrement reported, was similar to that observed following the ingestion of an alcoholic beverage resulting in a blood alcohol content of approximately 0.08% (the current UK legal driving limit), or while sleep deprived.
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK; Department of Human Physiology, Vrije Universiteit Brussel, Brussels B-1050, Belgium. Electronic address: pwatson@vub.ac.be.
authors.forename: Phillip
authors.initials: P
authors.lastname: Watson
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK; Sleep Research Centre, Loughborough University, Leicestershire LE11 3TU, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Whale
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Mears
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK; Sleep Research Centre, Loughborough University, Leicestershire LE11 3TU, UK.
authors.forename: Louise A
authors.initials: LA
authors.lastname: Reyner
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Maughan
mesh_terms: D000063:Accidents, Traffic / Q000523:psychology / Q000706:statistics & numerical data; D000293:Adolescent; D000328:Adult; D001334:Automobile Driving; D015992:Body Mass Index; D003072:Cognition Disorders / Q000209:etiology; D003681:Dehydration / Q000097:blood / Q000150:complications* / Q000652:urine; D004569:Electroencephalography; D004585:Electrooculography; D006801:Humans; D008297:Male; D009994:Osmolar Concentration; D011596:Psychomotor Disorders / Q000097:blood / Q000209:etiology* / Q000652:urine; D013997:Time Factors; D014556:Urine / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000502:physiology*; D055815:Young Adult
keywords: Cognitive function; Dehydration; Fluid balance; Road traffic accident