How much water do I really need?

We’ve all heard the same advice… 8 glasses a day of water, or 64 ounces…. MINIMUM! Is this even true? A lot of accepted wisdom ends up being bogus. As it turns out, so is this… sort of.

This old recommendation is technically true. We should get about 64 ounces of water per day, on average. Here’s the rub… that includes the water we derive from our food. Seeing as our food is already about 70-80% water, depending on the food, this ends up being a pretty trumped-up water recommendation. In most cases, we can do well with considerably less. However, for active people, this number changes yet again.

For avid exercisers, additional water should be consumed depending on duration and intensity of exercise. As a general rule, one should take in roughly an additional 8 ounces of water for every 15 minutes of moderate exercise. To make sure you’re taking in enough, an easy method is to weigh yourself before and after activity. If you weight the same after as you do before, you’ve taken in enough water during your workout. If you weigh less after exercise, take in about 64 ounces of additional water for every pound lost.

Ensuring adequate intake can be vital to performance. On average, a 1% drop in hydration equals a drop in performance of about 5%. Taking into account that we don’t generally feel thirsty until we’re about 3% dehydrated, this can mean a 15% drop by the time you even feel thirst. The key is to drink periodically throughout the day, staying ahead of your thirst. But how much do you need?

Determining a quantifiable recommendation is elusive. It is dependent on many factors: weight, body composition, age, activity level, diet, health status, medications, etc. The easiest way to ensure a decent intake is to drink periodically throughout the day just as a matter of course. This is usually easiest if you keep water with you. If it’s not in reach, you’ll tend to wait until you’re thirsty. To monitor how well you’re doing, the color of your pee is a good indicator. Contrary to conventional wisdom, clear pee doesn’t mean you’re properly hydrated. Odds are it means you’re OVER-hydrated. Your urine should be the color of lemonade… a pale yellow. That’s enough to aid your kidneys and to facilitate all your metabolic functions, as well as the myriad other functions water serves in the body, but not so much as to adversely affect electrolyte balance in the body.

The moral of the story is that we don’t need a gallon of water per day to keep from dehydrating. This is just another example (of many) of a researcher making a valid point, that point being taken completely out of context, then popular media running with the story and perpetuating false information.

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