You’ve likely heard the rule that you should drink eight glasses of water a day, but did you know that doing so could also make you a more pleasant person to be around?
According to two studies recently conducted at the University of Connecticut’s Human Performance Laboratory, even mild dehydration can alter a person’s mood, energy level and ability to think clearly. The study tested separate groups of young women and men, all of them healthy and active individuals – neither high-performance athletes nor sedentary – who typically exercised for 30 to 60 minutes per day.
Each of the participants took part in three tests to induce dehydration. After each test, they took cognitive tests that measured vigilance, concentration, reaction time, learning, memory and reasoning. The tests showed that it didn’t matter if a person had just walked for 40 minutes on a treadmill or had been completely at rest – the adverse effects from mild dehydration, defined as an approximately 1.5 percent loss in normal water volume in the body, were the same. In other words, says Lawrence E. Armstrong, one of the study’s lead scientists, by the time you feel thirsty, you’re already experiencing dehydration.
In the tests involving the young women, mild dehydration caused headaches, fatigue and difficulty concentrating, according to one of the studies, which appeared in the February issue of The Journal of Nutrition. Women also perceived tasks as more difficult when slightly dehydrated, although there was no substantive reduction in their cognitive abilities.
The tests involving young men (published in the British Journal of Nutrition in November 2011) bore similar results, with mild dehydration causing some difficulty with mental tasks, particularly in the areas of vigilance and working memory. While the young men also experienced fatigue, tension and anxiety when mildly dehydrated, adverse changes in mood and symptoms were substantially greater in females than in males, both at rest and during exercise, according to the study.
For many, these findings probably seem intuitive, but what do you think? Do the mood-boosting effects of staying hydrated make you more likely to drink those eight glasses of water a day? Or do you feel that studies such as these are overly prescriptive? Sound off here.