If you’re reading this: Drink a glass of water. You likely need it, as 75 percent of Americans are described as “chronically dehydrated.” While achieving a state of hydration might seem enviable and impossible, fret not because it’s doable. And the health benefits are not only encouraging, but they are also downright inspiring in the immediate short term, but especially in the long run. “Long-term hydration is the single best thing we can do to prevent chronic illness,” says Dr. Dana Cohen, an integrative medicine specialist in New York and coauthor of Quench: Beat Fatigue, Drop Weight, and Heal Your Body Through the New Science of Optimum Hydration.