New research from the University of East London and University of Westminster, suggests students who drink water during tests may improve their exam's results. One explanation might be due to the fact that water keeps the body hydrated.
Although researchers didn't take into account the details of their findings, Dr. Chris Pawson speculate that there might be several physiological and psychological effects which could possibly explain the findings of the study. One is that water might have an overall effect on the physiology of the brain's thinking capability and on the other, water might help relieve students from anxiety and stress which is known to lower exam performance.
The study included 447 undergraduate students which were monitored whether they took a drink during their exams or not. The type of drink was also taken into account. Although the research didn't determine whether the students actually drank, their research found that those students who had taken a drink during the exam had higher test results as compared to those who didn't.
No matter what the result is, Pawson still suggests students should drink during exams to keep them hydrated.