Losing 2% fluid of body weight may take toll on cognition: Research

While the effects weren't huge at 2 percent, they increased with increasing dehydration

Researchers found that athletes who lost fluid equal to 2 per cent their weight took a hit to their cognition. Even this mild to moderate level of dehydration- the loss of 2 pounds for someone who weighs 100 pounds and four pounds for someone weighing 200 — led to attention problems and impaired decision making, according to the report in Medicine & Science in Sports & Exercise.

In particular, dehydration led to impairment in tasks requiring attention, motor coordination, and so-called executive function, which includes things like map recognition, grammatical reasoning, mental math, and proofreading, for example.

“We’ve known that physical performance