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Unexpected Results: Dehydrated?

October 17, 2012

Back in February and March, I had my body composition tested as part of a nutrition program at my gym. I had 10.4% body fat the first time, and even lower, around 8% the second time. Really good numbers. Not quite as low as elite male athletes, but lower than most recreational male athletes, and far lower than the general male population.

I decided to get this test done again now, in the final run up to the Ironman. I want to lose 5-8 pounds before the Ironman. Before I get too aggressive about losing weight though, I want to see where my body fat is. Losing weight by losing a lot of muscle is not good! Being lighter weight means less weight to carry around the course. And for the run, that’s a really big deal. When I set my marathon PR in 2010 (in San Francisco of all places), I weighed 155 pounds — about 12 pounds lighter than now!

I was expecting my body fat to be around the same. My eating patterns have stayed fairly consistent, extremely healthy. I’ve put on a few pounds, but probably mostly muscle. I did not expect the results I got: 13% body fat! Now, 13% is considered very healthy by average male standards. But given my earlier results, it was not expected. But, my coach pointed out my intracellular fluid was down. My target should be 60+% intracellular fluid. In the beginning of the year, I had around 66%. This time, 58%. And dehydration can impact the test, skewing the results. Okay, so that body fat reading might be a little off, and make more sense.

But how could I be dehydrated? I am constantly drinking water. I use the restroom every hour or two. And I knew hydration was important for this test, so I had especially thought about drinking water in the days right before the test. I did have a long bike ride on Sunday, and did the test on Tuesday, but I thought I had fully rehydrated.

And then my coach hit on the problem. Salt. Without replacing enough salt, all that water passes through me. I knew this, of course, for proper water absorption, you need electrolytes. This is why marathoners who drink just plain water can have major problems. In endurance workouts, I think about electrolyte replacements. But I don’t think about it otherwise. I wasn’t trying to avoid salt in my diet. But I also wasn’t thinking much about adding it to my food. And I prepare a lot of my food fresh. And often with very minimal, if any, seasoning. Sure, I have things like canned beans and such that give me salt. But all my fresh veggies don’t.

I went in to the test expecting to learn how aggressively I could try to lose weight. I went out of the test with the surprising lesson that I need to be thinking about having enough salt in my food over the next month. My intracellular fluid levels will do a lot more for my Ironman performance than 5-8 pounds of body weight! Fortunately, that’s an easy enough fix. No major diet changes, just start sprinkling salt on my veggies and other dishes I prepare at home.

32 Days till Ironman Arizona!!


From → diet

  1. Heather Lako Lewis permalink

    Cool blog – I’m racing IM AZ as well and stumbled across your page. Getting nervous and excited! Good luck with last few weeks of training!

    • Jeff Kosbie permalink

      Good luck! Nervous and excited pretty much sums up the roller coaster I’m on right now too. Only a week and a half left for me before tapering.

  2. good job! That heat sounded absolutely brutal…it is one thing that definitely sucks the life out of our bodies!

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  1. BIA Retest… Much Better! « Jeff's Journey to Ironman Arizona 2012

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