A Simple Method to Calculate Your Sweat Rate

A lot of triathletes are able to train well and consistently with swim, bike, and run each week. However, sometimes they overlook the 4th discipline of triathlon and that is Nutrition/Hydration. I get asked all the time "What should I be drinking on the bike and run?" Well the answer to this is dependent on just how much you sweat out in a typical workout. Many athletes overlook the sweat test, and there are many out there that you can purchase online and do at home. But if you want a super simple and FREE version of the sweat test then keep on reading.

First, record your nude body weight prior to exercising. This means zero clothing on your body. You want to do the sweat test in a similar temperature to what you will be racing in, and you want to do the test for your half Ironman or Ironman pace run. This is most accurate because running involves using your entire body.

When you are finished running for one hour, dry yourself off the best you can and record your nude body weight again. Record what and how much you consumed of fluids (in ounces) during your exercise. Subtract your post-exercise weight (in ounces) from your pre-exercise weight (in ounces) and add the amount of fluid you consumed to that number. This will give you the amount of fluid you lost while doing that sport. Then you need to divide that number by the amount of hours you exercised for and that will equal your sweat rate. Make sure to record the weather conditions as well, because sometimes this can be a factor in your results.

1. ________ Record your nude body weight in ounces prior to exercise.

2. ________ Record your nude body weight after drying off best you can after exercise (convert weights to ounces; 1 lb = 16 oz).

3. ________ Record how much fluid you consumed in ounces during exercise.

4. ________ Subtract lines 1 & 2 from above for total weight loss and add line 3 (Line 2 - Line 1 +Line 3). This is the amount of fluid your body lost while exercising.

5. ________ Take the number from line 4 and divide it by how many hours you exercised for. This will give you and idea of what your sweat rate is.

The total formula is: (Line 1 - Line 2 +Line 3)/Line 4

In general, most athletes can get away with 2 bottles per hour and be ok, but sometimes if the fluid loss is more than 4 pounds you have to increase your salt intake and other supplements. I am not a nutritionist, so if that is your case, talk to a specialist in sports nutrition.

When I ask athletes to do a sweat test, it is most always on the run. There is less variables to factor in such as the cooling effect of the wind. Your sweat rate will vary between sports so if you want a sweat test specific to cycling then do it the same way as the run and go from there.

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