Next time before completing the eighth glass of water, remind yourself that hydration doesn't alone depend upon the amount of plain water you drink! It can also be absorbed from the different kinds of food that you consume. For example, if you eat fruits like watermelons, oranges, strawberries, and other citrus fruits that are comparatively high in water contents, your body will absorb a distinct amount of water. You can drink according to the total body water (TBW), It can be calculated using the Watson formula which is different for both men and women. So you don't have to rigorously drink water to follow the '8 glass rule'.
Fact
Everybody is familiar with this 8*8 rule of drinking! This misconception is evolved from the belief that a person will consume one ml of water per each calorie of food consumed. Thus, an average diet of 1,900 calories per day would dictate an intake of 1,900 ml (approximately 64 ounces) of water. However, people interpreted this as a recommendation to drink 1,900 ml of pure water, forgetting the fact that water is also found in abundance in the other liquids and foods that we consume. Drinking too much water can cause water intoxication, a severe electrolyte imbalance in which cells swell with excess fluid, and even death can occur.