How much water should I drink during exercise?

How much water should I drink during exercise?

Drink 5-12 ounces of water every 15-20 minutes.

As a general guideline, drink 5 oz. – 12 oz. of water every during every 15-20 minutes of exercise.

To be more specific:

Drink enough water so that you weigh the same or slightly less after exercise.
The goal is to weigh no less than 98% of your body weight after exercise.


John weighed 200 lbs before exercise.
He’ll want to weigh no less than 196 lbs after exercise.

Here’s the math:

200 lbs x 98% (0.98) = 196 lbs

If you lose weight during exercise, it does not mean you’ve lost fat. It means you’ve lost water weight and need to replace the water you’ve lost.  If you weigh less than 98% of your body weight after exercise, it means you’re very dehydrated.

Weigh yourself naked (if possible) before and after exercise because clothes that are drenched with sweat after exercise can add weight to the scale.

ACSM Position Stand: Exercise and Fluid Replacement
Beth Stover and Bob Murray. Drink Up! The Science of Hydration. ACSM’s Health & Fitness Journal. March/April 2007

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