Performing a Sweat Test

Performing a Sweat Test
The best way for runners to understand how much to drink is to perform a sweat test to see how much fluid they are losing during their runners. Here’s how to do a sweat test:

1.Get naked and weigh oneself on a scale
2.Get dressed and then run
3.Get naked again and re-weigh on the scale

The difference in the runner’s weight in the pre- and post-run weighing will be the amount of fluid lost during the run. It is important to be naked for these tests, because otherwise the runner’s clothing will just soak up the sweat. Performing a test like this several times under different temperature conditions will help runners see how much they are sweating and how much fluid they need to replace.

Replacing Electrolytes

In addition to fluids lost in exercise, electrolytes such as sodium, magnesium and potassium are being lost as well. These chemicals play important roles, such as helping to absorb fluids (sodium) and to avoid cramps (potassium). All runners will be losing these chemicals, but those who are especially salty sweaters will see a crusty white film on their skin afterward and should plan to take in even more of these chemicals.

The best way to replace electrolytes is through the use of a sports drink or electrolyte solution that contains a healthy amount of sodium and these other chemicals. Eating salty foods, such as pretzels, before and during workouts will also help add salt back in to the body. It is important to realize the drinking plain water does not replace sodium or other electrolytes and does not replace these substances.

Drink to Replace Fluids and Electrolytes
The bottom line is that all runners lose fluids and electrolytes through their sweat and must replace them to keep from becoming dehydrated and over-heated. It is important that all runners take the time to understand how much fluid they need to replace to ensure they are getting enough – and not too much – of what they need to keep healthy.