03/25/2026
Enter the Precision Fuel and Hydration Sweat Test. I selfishly tested myself as soon as I got it to find out what I was doing wrong. I thought for sure that I may be the saltiest sweater alive, or so I felt. I strapped the test on my arm and sat there for 15 minutes until the test tube filled with enough sweat to test. My results popped onto the screen and baffled me. 747 mg/liter of fluid. This is considered a low sodium amount compared to the average personās 1000 mg/liter.
I knew immediately that I had been fighting fire with kerosine. I was trying to take more electrolytes to solve my cramps but electrolytes werenāt my problem at all, hydration was. You see, there are 4 important variables to understanding your hydration:
Electrolytes- how much sodium you lose per liter of fluid that you sweat out
Water- how much fluid you sweat out
Time- how long are you training for
Conditions- how hot or cold is it, how humid, etc.
I was overdosing electrolytes which leads to hypernatremia. This causes cramps, fatigue, GI distress, and nausea. No wonder I was bonking so hard.
Getting electrolytes right is not about taking a certain amount per hour though. Itās about taking the proper ration to keep your electrolytes in constant balance. If the balance is off in one direction or the other you will have similar symptoms. The ratio of sodium to water that is specific to you is the gold standard.
Once you know your ratio you just need to dial it in for your bottle size. Since mine is 747 mg/L and I use 20 oz bottles, I need exactly 453 mg per bottle. Since you donāt have to be perfectly exact I use 500 mg per bottle.
If there is one test that I recommend people to have done to improve endurance sports, it is this one.