Recently during three consecutive weekends, I started dehydrating much earlier than last year and, oddly, bonking at or shortly after the 3-hour mark during my long bike rides. My 2014 Ironman training plan is significantly harder than last year so the nutrition and hydration plan I previously used was far from adequate. I was sweating significantly more and burning far more calories due to the increased effort. Plus, August and September are the two hottest months here in New Orleans. This August has not been particularly friendly to me! :)
I was talking to a friend and fellow triathlete, Andre, who mentioned I should do a sweat test to see if I am drinking enough during my rides and runs. I will discuss how to perform a sweat test but first I wanted to elaborate on my test results!
I sweat A LOT but I was still surprised with my findings! I performed the test during one of my weekday 1-hour runs that just happened to include 13 minutes of 5K pace interval work. I purposely waited until lunch time to do my run. It was 88 degrees F with a heat index of 94 degrees F. I weighed myself (undressed) and did my run (yes, dressed) in that summer oven. It is best not to drink water during the run to make the test easier; but with that heat, I took 7 ounces of water with me. Upon return, I allowed myself to cool off a little, stripped down, dried off, and weighed myself again. Even with accounting for the 7 ounces of water I drank during the run, I lost slightly over 5 pounds! I was shocked! 5 pounds of sweat equates to over 77 fluid ounces of water!
I emailed my friend and he mentioned that he once lost 116 fluid ounces during a sweat test! Can you believe that?! I was still in shock so I went on the web to see how much a typical person sweats. I found that the average person sweats ranged from 27 to 48 fluid ounces per hour of exercise. OK, I'm not average! :) I also learned that Alberto Salazar, a long distance runner, once recorded that he lost 125 fluid ounces per hour when he was training for the 1984 Summer Olympics! OK, I'm no Alberto Salazar whether you consider running or sweating! :) I read that excessive sweating can be classified as losing 2% of your body weight. For me, 2% would be slightly over 3.5 pounds. Well, I lost slightly over 5 pounds so I am definitely an excessive sweater!
I adjusted my nutrition but, more importantly, I adjusted my water intake during the following weekend's long bike ride. I went from 24 fluid ounces of water per hour to 32 fluid ounces per hour. I also doubled my intake of electrolytes to 1200 mg of sodium per hour. I did a 4-hour bike ride that included four 20-minute intervals followed by a 4-mile brick run where the first 2 miles I ran were near my 10K pace. When I finished the 4.5 hours of training, the heat index was at 99 degrees F! Sad thing is that I still got dehydrated! I was so dizzy! I was also seeing flashes of light (I like to call my paparazzi moment). As expected, I had to do more walking than running during the two miles back to my car! But this was still a successful weekend since I performed significantly better than the prior three weekends even with hotter conditions! A better nutritional and hydration plan helped but I still need to tweak some more to get it right! Is it Fall yet?
The sweat test I performed did only one thing, it only confirmed that I sweat a lot! A sweat test will provide different results each time since there are several variables - exercise intensity, temperature, and humidity. Change any one of them, or combination of them, and the sweat loss will be different. So, even though I lost over 77 fluid ounces in sweat in one hour, it does not mean I need to drink 77 ounces of water per hour on the bike or run. You need to test different water consumption rates during training to determine what works best for you!
I ended up performing a second sweat test a week later just to confirm I previously read my scale correctly! I ran first thing that morning where the temperature was 84 degrees F (88 degrees F heat index). This time my 1-hour run only included 9 minutes of interval work ranging between my 5K and 10K paces. The test showed that I lost slightly under 5 pounds.
- Weigh yourself naked before a training run of a measured time (30 or 60 minutes). I recommend running for 60 minutes since you do not sweat much at first due to the body starting out cooled off.
- It is easier if you do not drink any fluids during the run but if you do, record how much water you drank. Also, do not use the toilet between the two weigh-ins!
- After your run, cool off, towel off the excess sweat, and weigh yourself again in the buff.
- The amount of weight you have lost represents the water loss per hour if you ran 60 minutes.
- If you ran for 30 minutes, multiply the weight loss by two to get your hourly fluid loss.
- Do not forget to add the weight of any fluids you may have taken in during your run to the total weight loss!
After I created a quick and dirty spreadsheet to do my calculations (yes, I am an engineer; hence, I am a geek), I found a calculator online (www.triharder.com/THM_SwRate.aspx).
For future reference, I recorded my weight loss, the temperature, and heat index for both test! I may even perform a sweat test for each sport with varying weather conditions in the near future! A bike sweat test will be easy to perform. Swimming test may not be so easy since I tend to drink a lot of chlorinated water during my swims... And no, I don't pee in the pool but I do pee in the ocean. :)
I also plan to perform a bike and a run sweat test in early- to mid-October when temperatures start to cool off and the humidity is not nearly as bad. Based on those sweat tests, I will determine what adjustments I may need to make to my water and/or electrolyte intake for Ironman Florida. I do not want to drink too much during the Ironman! Drinking too much fluid and not taking in enough sodium is one way that leads to hyponatremia. Hyponatremia is caused by abnormally low levels of sodium in the blood! So drink up, but not too much! Gosh, why can't this be easy?!?!
Some interesting information about dehydration and hyponatremia. Notice in the below lists of symptoms for dehydration and hyponatremia how the first 4 items in each list are the same! So, you may be hyponatremia but believe you are dehydrated. So you drink more fluids making matters worst. Most times I dehydrate, I tend to get dizzy, start seeing flashes of light, and/or have my ears start popping like when flying in an airplane. From time to time I also get headaches and/or muscle cramps.
Symptoms of dehydration:
- Disorientation
- Fatigue
- Nausea
- Headache
- Muscle cramps
- Disorientation
- Fatigue
- Nausea/vomiting
- Headache
- Dizziness
- Seizures
- Coma
- Swollen hands and feet
- Breathing difficulties
- Muscle weakness
- Serum sodium levels
Please consider donating to my fundraiser for the Loeys-Dietz Syndrome Foundation (LDSF). Donations can be made at www.crowdrise.com/imfl.
For more information about the Loeys-Dietz Syndrome (LDS), please visit LDSF's website at www.loeysdietz.org.
No comments:
Post a Comment