The adult human body is made up of roughly 60% water, so it’s important to replenish water that is lost naturally throughout the day as we sweat, visit the restroom, and even breathe. All fluids can help the adult human body is made up of roughly 60% water, so it’s important to replenish water that is lost naturally throughout the day as we sweat, visit the restroom, even breathe. All fluids can help maintain a proper water balance in your body, but water — plain or sparkling — does so without providing extra calories or added sugar, so it’s a great idea to make it your first choice for daily hydration. maintain a proper water balance in your body, but water — still or sparkling — does so without providing extra calories or added sugar, so it’s a great idea to make it your first choice for daily hydration.