We all know that we should drink more water, but a 2012 study from two London universities shows that staying well-hydrated can actually improve exam scores by up to 10%.

The study looked at 447 psychology students attending the University of East London. Among those students, 71 of them were in their foundation year, 225 were first-year students and 151 were second-year students.

Only 25% of students entered the exam hall with a bottle of water. The students in their second year of study were more likely to bring water with them (31% vs 21% for foundation and first-years).

The researchers found that foundation students who stayed hydrated could see grades improve by up to 10%. First-year students could see an improvement of up to 5% and second-years up to 2%.

Water-drinking students could expect to see an average of 4.8% improvement in their grades.

Need more proof that staying hydrated improves your exam performance?

A study from 2010 helps prove the opposite side of the spectrum. The small study found that dehydration decreased exam performance. During the study, 10 students with the average age of 17 completed an intense cycle ride to simulate dehydration before taking an exam.

Participants were mildly dehydrated when going in for the exam, and took the Tower of London test. Those who were dehydrated had to exert more effort to achieve the same results as those who were well hydrated.

An article, originally published in Nutrients in 2011, took a look at four small studies that demonstrated the importance of staying hydrated. The studies found that children between the ages of 7 and 9 had longer attention spans and better memory function when they were properly hydrated.

Other studies have shown that dehydration can affect cognitive function, increase anxiety, and lead to fatigue or depression. In fact, there is evidence that sipping water during an exam can ease anxiety. Along with helping improve cognitive function, drinking water can break the chain of negative thoughts and help ease anxiety.

In adults, research has shown that restricting fluids – to the point of losing 1% of body weight – can decrease alertness and concentration.

Research and studies have helped prove the beneficial effects of staying hydrated when taking exams. But drinking water in general is important for the human body. After all, we are made up of 75% water. There’s no greater reason to start drinking more water each day.

About the Author: After spending a number of years in the plumbing industry, Mark Fear decided to create Softer H2O in an attempt to help improve drinking water quality across America. If you wish to find out more about water quality then check out SofterH2O.com.