Working outside without fluids (especially in the hot summer sun) for just two hours is enough to cause dehydration sufficient to impede concentration, according to a study from the Georgia Institute of Technology (Georgia Tech) in Atlanta.
or this study, the researchers analyzed data from 33 peer-reviewed research papers on dehydration and cognitive abilities, including attention, coordination, complex problem solving, and reaction times. They discovered that, while fluid loss has a minimal effect on reaction times, it can have a major impact on cognitive functions that require focus. As study participants became more dehydrated, they made more errors in repetitive tasks, as well as higher-order functions like complex problem solving.
The Georgia Tech researchers found that severe impairments in cognitive function begin at around 2 percent of body mass loss due to dehydration – a 4-pound fluid loss in a person who weighs 200 pounds. According to the researchers, most people feel poorly at a 4 percent fluid loss. Older adults and people who are severely overweight are at higher-than-normal risk for dehydration.
Sourced from: Medicine & Science in Sports & Exercise