In what is called a metadata analysis, researchers have combed through the results of numerous studies, and come to the definitive conclusion that dehydration blunts concentration, with the effects manifesting themselves as dopiness in our normal, everyday behaviour.
The team behind the analysis, from the Georgia Institute of Technology, reported that attention, coordination, reaction speed and problem solving were all significantly affected by dehydration.
"The simplest reaction time tasks were least impacted, even as dehydration got worse, but tasks that require attention were quite impacted," said Mindy Millard-Stafford, a professor in Georgia Tech's School of Biological Sciences.
Repetitive, less stimulating tasks were found to be impacted highly in a majority of test subjects relating to the effects of dehydration on cognitive function.
"Maintaining focus in a long meeting, driving a car, a monotonous job in a hot factory that requires you to stay alert are some of them," said Millard-Stafford. "Higher-order functions like doing math or applying logic also dropped off."
According to the metadata analysis published in the journal Medicine & Science in Sports & Exercise, cognitive decline occurs when the body loses just 2 per cent of it’s body weight due to sweat or dehydration.
"There's already a lot of quantitative documentation that if you lose 2 percent in water it affects physical abilities like muscle endurance or sports tasks and your ability to regulate your body temperature," Millard-Stafford explained. "We wanted to see if that was similar for cognitive function."
The findings, based on the data from a whopping 6591 studies, indicate a danger for workers, particularly those who spend long periods of time in the sun and operate heavy machinery.
However, as with all great studies, there is also a frustrating flip side to the research. While hydration and adequate water intake is the obvious strategy to overcome dehydration and the associated drop in concentration, the researchers have also warned workers against over-hydration.
"You can have too much water, something called hyponatremia," Millard-Stafford explained. "Some people overly aggressively, out of a fear of dehydration, drink so much water that they dilute their blood and their brain swells."