Here’s How Much Water You Should Actually Be Drinking

Sixty-four ounces of water, eight 8-oz. glasses a day. It’s what we’re all supposed to be drinking, right? Wrong. Well, for some of us.

It turns out the eight glasses rule doesn’t exactly apply to everyone, and yet, many still believe in that magical number—perhaps because it’s easy to remember?

It is believed the “8×8” idea began in 1945 with a Food and Nutrition Board recommendation. There was one little sentence included with the recommendation, however, that said, “Most of this quantity is contained in prepared foods.” While many sources do say food and other beverages count, that last line in the original recommendation seems to have been left off as it was passed down throughout the years.

In actuality, the amount of water each person needs depends on the individual.

“Fluid needs are dynamic and need to be individualized from person to person,” Dr. Robert A. Huggins, of the University of Connecticut, told Health. “Factors such as sex, environmental conditions, level of heat acclimatization, exercise or work intensity, age, and even diet need to be considered.”

To put it simply—tuning into your thirst is the best way to figure out when to drink. A study led by Monash University also found that when you’ve had enough to drink, it physically becomes difficult to swallow. Basically, listen to your body.

Aside from just being thirsty, your body will also give you signals that you need to up your hydration. If you’re tired, constantly hungry or have a headache, consider a trip to the water cooler.

If you find you do need to be drinking more water, here are some products to help. Or, you can try the rubber band trick: Place rubber bands around a water bottle and add a band to your wrist each time you refill and finish the bottle. If you can’t stand the thought of drinking so much water, these foods and other beverages are also a good source of hydration.

Alas, if you still want to be a stickler for the rules and really need a specific quantity of water you should be drinking, check out this hydration calculator.