If you don't like water or just don't drink much water, you may be dehydrated. Mild dehydration is defined as 1.5% loss in normal water volume in the body. And two recent studies with men and women find that beyond affecting your body, mild dehydration can impact your mood. Researchers evaluated 51 healthy men and women three times in three months. All the subjects walked on a treadmill to induce dehydration. The researchers then tested the subjects' alertness, concentration, reaction time, learning, memory, reasoning, and mood level. And they found that dehydration in men caused difficulty in memory and alertness. In women, dehydration caused little reduction in cognitive ability but did cause significant fatigue, tension, and anxiety. Such changes in mood occurred regardless if the subject was exercising or at rest. The results of the study with male participants were published in the "British Journal of Nutrition" and the women's results were in the "Journal of Nutrition," an American publication. So, you don't need to be performing in a triathlon even if you're desk-bound, and especially if you're a woman. Your body and your brain might need a shot of H20.