Why my ultimate exam tip is an exam sip!

As the Junior and Leaving Certificate exams kick off today, I want to wish you all good luck and to remind you not to forget to bring a bottle of water with you into your exams!

It’s that time of the year again when the two big state exams – junior and leaving certificates kick off for a generation of Irish youths.  The leaving cert is the hardest exam I’ve ever had to sit  – throughout my years as a student in University, and afterwards working in a laboratory as a neuroscientist, nothing really compared to the intensity of that exam.  

Drink water to improve your grade!

Scientists from the University of East London report that bringing a bottle of water with you into your exam boosts your grade. Students who brought water with them did better in the exam than those without water.  The researchers accounted for the 447 undergraduate students’ prior grades, so it’s not just a matter of smarter students being more likely to bring a bottle of water into the exam.

Drinking water makes you smarter

Controlling for ability from previous coursework results, scientists found those who drank water during the exam scored an average of 5% higher than those who did without.

The ultimate exam tip – is an exam sip!

Scientists explain that there may be a few reasons for this link between bringing water (and presumably drinking it) and better grades:

  1. Previous studies have shown that a dehydration level of just 1% of your body weight reduces your thinking functions, so it makes sense that drinking water improves mental performance.
  2. The desire to drink water (thirst) is driven by a small protein (a peptide) called vasopressin in the brain. Vasopressin has also been implicated in making new memories and with the positive feelings associated with social behaviour thereby leading to a better performance by reducing anxiety in an exam situation,
  3. By offering a momentary distraction – taking a sip of water – drinking water may also break a chain of thoughts and free the mind to focus on the task at hand, leading to better performance – thereby reducing anxiety during the exam.
  4. Drinking water might also just activate a placebo affect – if you believe water boosts your brain power, that belief alone could improve your performance.

The research continues – either way, don’t forget that bottle of water on your next exam.


Lim MM, Young LJ (2004). “Vasopressin-dependent neural circuits underlying pair bond formation in the monogamous prairie vole”. Neuroscience 125 (1): 35–45.