1. It will help you de-stress. Being sure to sip water throughout a stressful day can soothe stress-induced symptoms as diverse as headaches, tense muscles, fuzzy thinking, a pounding heart, and low energy. That's because stress taxes all your basic body systems -- and when you're dehydrated, the effects are magnified. Water won't wash your stressors away. But it can provide you with more energy, ease tension, slow breathing, and reduce the strain on your heart.