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Jul 18, 2010
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Sweat Rate and Hydration Levels

Here we are smack dab in the middle of the summer heat sweating our bums off. If your working out outdoors, staying hydrated can be a challenge.

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Today I did a little hydration test to see if I could stay hydrated during my run. I weighed myself (without clothes) before and after my run. In apporximately one hour I stopped at three water fountains. Two during my run and one after. I came home, took off my clothes and stepped on the scale. I was down 3 pounds!!! Which means I lost 3 pounds of fluid during one hour of running!

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Losing as little as 2% of your body weight can cause an increase in perceived effort and a decrease in performance. Which means my workouts are physically and mentally harder because I’m not drinking enough water. Silly me.

It’s hard working out in this heat and I’ve been making it even harder with my poor hydration levels.

I know I have a high sweat rate, but I was astounded at the results. Here’s how to tell if you are properly hydrating for your run.

  • Weigh yourself without clothes on before your run.
  • Weigh yourself as soon as you return home from your run.

To read more on hydration and to find out how to replace the lost fluid check out The Candid RD’s post on Fluid Recommendations.

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Comments

  1. Jenna says

    July 18, 2010 at 1:58 pm

    Wow, I never really would have thought about a sweat rate and the hydration after a workout in the heat! I obviously drink a ton of water after any form of exercise but wow, probably not nearly enough!

    Reply
  2. Madeline - Greens and Jeans says

    July 18, 2010 at 2:03 pm

    Training for a marathon during an Arizona summer has turned me into a hydration machine! I am not a Gatorade fan, so coconut water has really saved me

    Reply
  3. Rosey Rebecca says

    July 18, 2010 at 2:54 pm

    Thanks for this post! I weighed myself after a run the other day and I was two pound lighter and didn’t know why! Glad you cleared that mystery up!

    BTW-tomorrow or Tuesday I am having a giveaway on my blog that has something to do with one of the pics in the post. 🙂

    Reply
  4. Jody - Fit at 52 says

    July 18, 2010 at 3:00 pm

    I am with you on this! I always do that & for me, it is about 1.5 pounds so I guess I am hydrating OK since I do a pretty hard core workout! Good info especially with this heat to make sure people stay hydrated!

    Reply
  5. Laury @thefitnessdish says

    July 18, 2010 at 5:50 pm

    Great tips on weighing yourself before and after a run for hydration status…I did not have a run this weekend, but it was SUPER hot and I was outside….and did up some coconut water in a watermelon smoothie to stay hydrated! It’s SO important!!! I feel for you running in this heat!!! Sure it was rewarding though!

    Reply
  6. BostonRunner says

    July 18, 2010 at 7:12 pm

    Great tips! I’ve been really trying to hydrate during these hot and humid days we’ve been having!

    Reply
  7. Sarena (The Non-Dairy Queen) says

    July 18, 2010 at 7:22 pm

    That is pretty interesting to do a test like that. I will definitely be checking it out tomorrow when I work out!

    Reply
  8. Andrea@WellnessNotes says

    July 18, 2010 at 7:25 pm

    Great reminder! I’ll have to do the hydration test…

    Reply
  9. Sarah from 20somethingcupcakes says

    July 18, 2010 at 8:00 pm

    I’ve been wanting to try this coconut water. I’ve heard it’s even better than Gatorade for replenishing after a run!

    Reply
  10. Theodora says

    July 18, 2010 at 8:48 pm

    So your run was as hellish as mine this morning??

    Reply
    • Jess says

      July 18, 2010 at 9:00 pm

      Yes, Theodora it was hellish. =)

      Reply
  11. Christine (The Raw Project) says

    July 18, 2010 at 9:10 pm

    Great post and tips, hydration has been a major challenge here too with our triple-digit dry heat. I just ordered a new hand held water bottle for running that I can’t wait to try, but I also need to start weighing myself as my runs get longer.

    Reply
  12. Jill says

    July 18, 2010 at 9:56 pm

    Thanks for that! I’m terrible at hydrating because I rarely get thirsty. Have to make it a priority in this heat!

    Reply
  13. Alex @ IEatAsphalt says

    July 18, 2010 at 11:27 pm

    Did you have any cramping with the coconut water? For whatever reason my body gets super sensitive to any liquids too close to when I start running. And stopping for water always ends terribly for me.

    Reply
  14. Cara says

    July 19, 2010 at 5:39 am

    That’s a neat little test. Hopefully you drank your body weight back again 🙂

    Reply
  15. The Candid RD says

    July 19, 2010 at 6:59 am

    Thanks so much for the link to my post!! I’m glad the information was helpful. I completely believe that you lost 3 lbs of water weight during your run. This is why I workout indoors during this time of the year, I simply KNOW I can’t keep up with my sweat, and I’m not really into running anyway so it doesn’t really bother me to stay inside.
    Glad you’re taking some good advice and (attempting to) staying hydrated. I LOVE a nice cup of coconut water after a sweat session!

    Reply
  16. Joanna Sutter says

    July 19, 2010 at 8:26 am

    I don’t run (blush) but I drink like a camel during my rides and lifts. It’s the rest of the day when I’m a bit of a slacker on the H2O!

    Reply
  17. Simply Life says

    July 19, 2010 at 8:50 am

    Wow, that is crazy to think about how much hydration we could lose exercising – thanks for the reminder!

    Reply
  18. Nichole says

    July 19, 2010 at 9:18 am

    Good call on weighing before and after, never really occurred to me. When you are running with that intensity, you need the full on calories, electrolytes, etc from a proper sports drink.

    Reply
  19. Heather says

    July 19, 2010 at 11:41 am

    I need to try weighing myself before and after a run. On Saturday, after running, I ended up sleeping for almost 2 hours – I only ran 3 miles! I drank 3-4 glasses of water but maybe it wasn’t enough – this would be a good test.

    Thanks for the tip!

    Reply
  20. Kat (BubbleGum Gym Kat) says

    July 19, 2010 at 12:54 pm

    3LBS whoa that is a ton!!! I need to try that and see. I always have my water with me though and at least drink two bottles..so who knows.

    Reply
  21. FoodFitnessFreshair says

    July 19, 2010 at 1:34 pm

    That’s crazy that 3 pounds were lost in just one hour! It shows just how important it is to stay hydrated. I know that when I’ve ran in the intense heat and haven’t properly hydrated I’ve gotten to the point of feeling a little light headed before, and that’s certainly no fun!

    Reply
  22. Stacey @ Tipping the (Kitchen!) Scales says

    July 19, 2010 at 3:55 pm

    I find it hard to drink enough sometimes whist running because there aren’t any water fountains on my route (or anywhere in the UK for that matter!) and I don’t like to carry a heavy bottle. I generally take about 250ml with me on runs that are over 40 minutes and nothing for a shorter run.

    Reply
  23. nycgirl0501 says

    July 19, 2010 at 4:55 pm

    Interesting! I will have to try that. I know yesterday I did not have enough water because my legs hurt all day. As soon as I hydrated I felt better.

    Reply
  24. Jennifer says

    July 19, 2010 at 7:23 pm

    Wow 3lbs in an hour?!?

    BTW, I love ZICO! I am posting a review about it this week!

    Reply
  25. Averie (LoveVeggiesAndYoga) says

    July 19, 2010 at 8:08 pm

    whoa love me some coconut water, too! and yes hydrating in the summer is soooo important!

    Reply
  26. Kelly Olexa says

    July 24, 2010 at 3:42 pm

    OMG I was just talking about this Coconut Water thing with running on my blog this week! I have to get some right away. Do you love it?

    Reply

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I'm Jess Underhill, a certified run coach and freelance fitness writer. I experienced my first runner’s high when I was 13 and it had a profound impact on how I saw myself and this world. My mission in life is to help people chase down their personal bests and crush their goals so that they too, can change their perceptions. Read More…

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