As a general guideline, drink 20 oz. - 24 oz. of water for every 1 lb of body weight you lose during exercise. Drink this water within 2 hours of completing your exercise.
Example:
John weighed 200 lbs before exercise.
John weighed 198 lbs after exercise.
He lost 2 lbs during exercise.
John will want to drink 40 oz. - 48 oz. of water within 2 hours of exercise.
Here’s the math:
2 lbs x 20 oz. = 40 oz.
2 lbs x 24 oz. = 48 oz.
If you lose weight after 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.
Sources:Weigh yourself naked (if possible) because clothes 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




