How Long Does It Take to Get Hydrated?

Hydration is important, but it’s easier to restore than you think. New science shows all it takes is a couple glasses a water, not even an hour before your workout.

How long does it take to get hydrated before training? Just 45 minutes, says a recent study from the Journal of Strength and Conditioning Research. Challenging the popular notion that complete hydration requires you to drink yourself into a water-induced coma, this study shows that just 600ml of water ingested 45 minutes prior to training is enough to take an athlete from mildly dehydrated to fully hydrated.

The study was conducted on ten recreationally active men and women, each about 25 years old and weighing close to 160 pounds. They were all instructed to arrive at the testing lab dehydrated. Hydration status was determined by measuring urine specific gravity – they peed in a cup. Then the subjects were fed a variety of water-based solutions: pure water, Gatorade, and something in-between. Hydration was measured again at 30, 45, and 60 minutes after drinking.

Participants went from mildly dehydrated to fully hydrated in 45 minutes by consuming 600mL of water. That’s less than two bottled waters. Researchers also found no difference between water and Gatorade for achieving hydration. What does this mean for you?

First, this study is only applicable to getting hydrated before exercise, and the participants were only mildly dehydrated. They had not just finished a half-marathon in the Mojave Desert, which would have required more than 45 minutes and 600mL of water for recovery. So as your workout approaches, drink a couple glasses or bottles of water in the hour prior. This will ensure you perform your best.

Finally, don’t worry about drinking some magic concoction of salt, ginseng root, and unicorn blood to get hydrated before your workout. Plain old water will work just fine. But post-exercise is a different story. Research has shown that after you lose significant water during intense exercise, a drink containing electrolytes will help you rehydrate more quickly than water alone.

Personally, I’m stoked that I don’t have to visit the urinal every thirty minutes starting at 8:00AM just to get hydrated for my afternoon workout. Of course, for that half-marathon in the Mojave I might get started early, but it appears that a couple glasses of water and 45 minutes are plenty to prepare most of us for training.


1. Heather Logan-Sprenger and Lawrence Spriet. The Acute Effects of Fluid Intake on Urine Specific Gravity and Fluid Retention in a Mildly Dehydrated State. Journal of Strength & Conditioning Research: April 2013. Vol 27. Issue 4. p1002–1008. doi: 10.1519/JSC.0b013e31826052c7

Photo courtesy of Shutterstock.

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