According to a recent article (and I apologize for not having retained the source) approximately 75% of Americans are chronically dehydrated. Also, lack of adequate water is the #1 trigger of daytime fatigue. The author of this article also noted that a mere 2% drop in body water can trigger fuzzy short-term memory, trouble with basic math, and difficulty focusing on the computer screen or on a printed page.
Early signs of dehydration include fatigue, muscle weakness, poor concentration, fogginess, headaches, stiff joints, dry eyes or nasal passages, and dry mouth. Further dehydration may lead to depressive symptoms like moodiness, apathy, sleep disturbance, anxiety, tension, hypertension, overeating, and higher blood cholesterol.
The message here is simple and obvious. Increased energy and less mental confusion make increased water consumption an easy and excellent way to contribute to your overall mental well-being.