Drinking plenty of water is essential to staying hydrated, but sometimes, H20 alone doesn’t cut it, says Dr. Matthew Sedgley, a physician specializing in sports medicine at MedStar Health. Those who do strenuous exercise, have a labor-intensive job or spend long periods in the heat may also need to replenish their electrolytes. “Electrolyte is a fancy word for minerals like sodium, potassium and magnesium, and they’re substances our bodies need to function,” he says. “Your body uses them as you do physical activity, which makes replacing them important.” Mixing electrolyte powder into your water is a fast and convenient way to do that, says Amy Goldsmith, a registered dietitian specializing in sports nutrition who owns Kindred Nutrition & Kinetics. These powders often come in pre-measured packets, so you know exactly how much of each mineral you’re getting, and they’re available in various flavors, so they taste good.…