Mild Hypohydration Increases the Frequency of Driver Errors During a Prolonged, Monotonous Driving Task

The aim of the present study was to examine the effect of mild hypohydration on performance during a prolonged, monotonous driving task. Eleven healthy males (age 22 ± 4 y) 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 120 min driving simulation task began. Driver errors, including instances of lane drifting or late breaking, EEG and heart rate were recorded throughout the driving task. 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). 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.


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  • Accession Number: 01609608
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 4 2016 10:43AM