According to two new studies from University of Connecticut's Human Performance Laboratory, even mild dehydration can have a significant impact on a person's mood, energy levels and mental performance.
Water levels determine how good we feel
Test results show no difference between taking a 40 minute walk or sitting at a desk. Lawrence E. Armstrong, professor of physiology at University of Connecticut, lead study researcher and hydration expert with over 20 years experience, stressed on the importance of staying hydrated throughout the day, regardless of the level of physical activity one is engaged in.
"Our thirst sensation doesn't really appear until we are 1 or 2 percent dehydrated. By then dehydration is already setting in and starting to impact how our mind and body perform. Dehydration affects all people, and staying properly hydrated is just as important for those who work all day at a computer as it is for marathon runners, who can lose up to 8 percent of their body weight as water when they compete," said Dr. Armstrong.
Two distinct groups of young, healthy and active individuals were tested in the studies. 25 women with an average age of 23 years took part in one trial, while a separate group of 26 men, averaging 20 years of age, took part in the second trial. All participants were subjected to three evaluations that were separated by 28 days break. The participants were first asked to walk on a treadmill to induce dehydration, after having been properly hydrated the night before. Next, the research team measured the participants' cognitive skills, including vigilance, concentration, reaction time, learning, memory, and reasoning. These results were compared to test results obtained when the participants were not dehydrated.
Women shown more vulnerable to dehydration symptoms
Although no significant reduction in cognitive skills was noted, the women's group reported that mild dehydration caused fatigue, headaches and difficulty concentrating. This particular study is featured in the February issue of The Journal of Nutrition.
For the men's group, mild dehydration caused some difficulty with mental tasks that involved vigilance and working memory. Men also reported fatigue, tension and anxiety. However, the research team noted that dehydration symptoms were "substantially greater in females than in males, both at rest and during exercise". The study involving men has been published in the November 2011 issue of the British Journal of Nutrition.
Harris Lieberman, study co-author and research psychologist with the Military Nutrition Division of the U.S. Army Research Institute in Natick, explained that "Even mild dehydration that can occur during the course of our ordinary daily activities can degrade how we are feeling, especially for women, who appear to be more susceptible to the adverse effects of low levels of dehydration than men. In both sexes these adverse mood changes may limit the motivation required to engage in even moderate aerobic exercise. Mild dehydration may also interfere with other daily activities, even when there is no physical demand component present."
The scientists don't yet know why women are more vulnerable than men to the effects of mild dehydration. Researchers believe that it may be part of an ancient survival mechanism that alerts us that we need to rehydrate ourselves. //Michelle Bosmier, NN