Image of Sweat Composition

Sweat Composition and Electrolyte Replacements

Learn which hydration beverage most closely matches the composition of your sweat

written by Olivia Crozier

Understanding your sweat composition is an integral step in better understanding your unique hydration needs. Continue reading to learn more and how to calculate the electrolyte content of your beverage of choice.

Defining Sweat Composition

Along with fluid losses and electrolyte losses, the Nix app also calculates your personal sweat composition - a measure of the concentration of electrolytes in your sweat. Your unique sweat composition is reported as the number of milligrams of electrolytes you're losing per ounce of sweat. Sweat composition can vary drastically from one person to the next. For example, some athletes will see their composition below 20 mg/oz while others are over 100 mg/oz. This further demonstrates how differently people sweat and how hydration strategies should be highly personalized for peak performance. With this metric, you can begin to understand the best electrolyte drink you should be consuming based on your personal biology and training environment.

Sweat composition is presented in the Nix app in mg/oz. The app also contains a convenient reference chart of the electrolyte content of popular beverages in mg/oz. However this can also be calculated directly from the nutrition label on your favorite sports drink or drink mix by reviewing the list of electrolytes.

How to calculate electrolyte content:

Example: Skratch High- Sodium

Skratch High-Sodium (previously Skratch Hyper)

16 fl oz, 1 packet

Step 1 - Tally total electrolytes in single serving (include: sodium, potassium, magnesium, calcium, and chloride):

1,720 mg sodium + 3 mg calcium + 150 mg potassium = 1,873 mg per packet

Step 2 - Confirm suggested amount of water for single serving:

Label indicates to use 16 fl oz per 1 packet

Step 3 - Calculate composition (volume of electrolytes per ounce of fluid):

1,873 mg electrolytes / 16 oz water = 117.1 mg/oz

Based on the electrolyte composition of Skratch High-Sodium, this mix might be best for you if you have a sweat composition around the range of 110-130 mg/oz.

Example: Nuun Sport

Nuun Sport
16 fl oz, 1 tablet

Step 1- Tally total electrolytes in single serving:

300 mg sodium + 13 mg calcium + 150 mg potassium = 463 mg per tablet

Step 2- Confirm suggested amount of water for single serving:

Label indicates to use 16 fl oz per tablet

Step 3- Calculate composition (volume of electrolytes per ounce of fluid):

463 mg electrolytes / 16 oz water = 28.9 mg/oz

Based on the electrolyte composition of Nuun Sport, this product may be optimal for you  if you have a sweat composition in the range of 25-35 mg/oz.

Which electrolyte drink is best for you based on your individual sweat composition?

Based on your sweat composition (mg/oz) use the Hydration Beverage Chart below to determine the best drink tablet, powder or liquid for you. Use the X axis to identify where you best fall based on your sweat composition. From there you can identify which of the electrolyte drinks best match your needs. This chart showcases popular drinks and is periodically updated within the Nix App.

The Nix app provides a reference chart of a number of popular electrolyte drinks based on your personal Sweat Composition