Instead of other less desirable substitutes, drink water when you are thirsty. If you’re choosing water as your main source of fluids, you probably won’t need to worry about how many glasses or ounces you consume each day. Trying to drink gallons of water a day in no way adds additional benefits to your health regimen. In fact, this can actually disrupt the normal potassium and sodium balance in your cells. When such disruption occurs, you find yourself retaining fluids because potassium is being lost.
In addition, as you get older, your sense of thirst may diminish and you may find yourself taking insufficient water. Yet, if you’ve been paying attention to your water needs over time, this is unlikely to happen because you are more attuned to your real thirst.
General Rule: ½ your body weight in ounces daily