Most people, especially teenagers, struggle with the balance of drinking water, with most people either drinking too much water and having to use the bathroom constantly or drinking too little water and feeling dry and thirsty constantly. When trying to get their drinking into shape, most people follow the classic idea that they should drink 8 glasses of water a day. Though 8 glasses may be enough for children or tween, adolescents and adults actually need to drink much more than that for optimum hydration. If 8 cups isn’t enough, then what is? 

According to MDLinx, no scientific study has ever concluded that we must drink 8 glasses of water per day. The likely origin of the oft-quoted advice may be a 1945 publication from the National Research Council’s Food and Nutrition Board that stated that an “ordinary standard” of water for adults is 1 mL for each calorie of food. So, a person who eats 2,000 calories per day would require 2,000 mL of water, or roughly 8 cups. In later years many studies contradicted and eventually disproved this theory. Some studies established a similar standard which was just “drink when you are thirsty!”. On the basis, this makes sense, but according to the Mayo Clinic, thirst isn’t a helpful indicator of hydration. In fact, when you’re thirsty, you could already be dehydrated, having lost as much as 1 to 2 percent of your body’s water content. 

Americans get nearly 20% of their fluid intake from food, according to the What We Eat in America component of the National Health and Nutrition Examination Survey. The remaining 80% of fluid intake comes from beverages, of which only a little more than one-third is plain water. Other beverages include soft drinks, coffee, and alcohol. The U.S. National Academies of Sciences, Engineering, and Medicine determined that an adequate daily fluid intake is: About 15.5 cups (3.7 liters) of fluids a day for men. About 11.5 cups (2.7 liters) of fluids a day for women. To help you establish a baseline, you can use the following rule-of-thumb equation described in the U.S. News & World Report. In short, the equation tells you to take half your body weight, and drink that amount in ounces of water.