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The Science of Hydration — and Taking the Proper Hydration Propel Fit Challenge!

This is a sponsored post brought to you by Propel. For our sponsored post policy, click here.

I feel like I’m pretty good about staying hydrated. I drink water throughout the day and with meals. I take my Propel and a water bottle to the gym. And I’m not shy about looking at the color of pee. So when it was my turn to take the Propel Add Flavor Challenge (you didn’t miss Erin’s and Kristen’s posts on it, did ya?), which this month is to hydrate properly for one full week, I felt pretty confident. Staying hydrated? Yeah, I got this.

And, then I had the amazing opportunity to chat with Laura Daray, scientist at the Gatorade Sports Science Institute, about the science behind proper hydration — and it was mind blowing. Yes, pee color is involved, but there’s so, so, so much more. And it’s fascinating how much it can vary from person to person.


For my challenge, Laura had me write down my weight pre-exercise (I weighed in on my pretty reclaimed scale!), the weight of my workout beverage pre-workout, my workout type and duration, my weight post-exercise, and the weight of my beverage once I was done with my workout (this is the workout I did). From that information, Laura calculated my estimated sweat rate. This rate gives you an estimate of how much fluid you lose through sweat in a particular environment. Since every person has a different sweat rate, the results of it then helped Laura to create my very own personal hydration strategy.

My Sweat Rate

And guess what? I was a Little Miss Overachiever in the hydration department and designated as a “light” sweater, meaning I actually drank more than I needed …

  • Workout Duration: 25 minutes
  • Body Weight Change: + 0.2 lbs
  • Fluid Consumed: 260 mL
  • % Dehydration: 0.15%
  • Estimated Sweat Rate: 0.4 L/hr (light)

My Personal Hydration Strategy

So my personal hydration strategy looks like this:

  • Monitor urine color throughout the day. Look for “light like lemonade” (pale, light yellow) as an indication of proper hydration (most of the time my pee is more clear, which Laura said is a sign of over-hydration).
  • Aim to begin all workouts in a hydrated state.
  • Practice a fluid replacement plan during my workouts based on my sweat rate. Based on my data, that’s about 14 ounces per hour. But it may be more or less as intensity and/or environment vary.
  • Aim to replace both fluid and electrolytes (sodium) lost through sweat.
  • Ensure rehydration after a workout with about 20 to 24 ounces of fluid (including sodium) per pound lost.

How I’m Staying Properly Hydrated — With the Challenge and Beyond

Isn’t that level of detail awesome?! It’s way better and more individualized than most of the hydration tips you read. I put this in practice for a week and loved it so much that I’m going to try to make it a habit! Now every time I pee, I look for that light yellow color and change how much water I’m drinking based on that. During workouts, I don’t just drink water but make sure I’m drinking Propel, so that I’m also getting electrolytes in my system which help with proper hydration. I even got a new 26-ounce water bottle that has ounce markers on the side of it, so that I can pre-plan how much Propel to bring to a workout and make sure I drink it during the workout. Once the workout is over, I go home, check my weight and fill it back up with the appropriate amount of water and Propel (although, I’ve found that since better monitoring my hydration and drinking during the workout, I’m pretty good about not losing water weight during the workout).

The temps and humidity have really gone up here in Kansas City recently, so I’ve had to play with my sweat rate a bit here recently, but I’m getting the hang of it — and I’m feeling really good during workouts and after. My energy is up a bit, and because I’m not overhydrating (and I’m hydrating properly with electrolytes), I’m not running to the bathroom as much — bonus!

I really learned SO much during this #PropelFit Challenge and will continue to use my new strategy to continue to stay properly hydrated. If you’d like to stay properly hydrated, too, be sure to enter to win an awesome Propel prize pack here — we’ll be picking a winner soon!

And, I’m dying to know: do you know what your sweat rate is? Do you think you’re hydrating properly? Eye-opening, I say! —Jenn

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