Why Sweat Testing?

Sweat is not just water and not all sweat is created equally. Sweat also contains electrolytes and the one most prevalent in sweat and most impactful to stay on top of is sodium. Sodium is a critical electrolyte for maintaining hydration, keeping muscles firing, and supporting brain function and blood volume. Here’s the catch: everyone’s sodium loss is different. Some people lose as little as 200 mg/L, while others lose up to 2000 mg/L. By testing your sodium loss, you’ll get the insights you need to fine-tune your hydration and stay at the top of your game.

Why Get Your Sweat Tested?

Understanding your sodium loss means you can tailor a hydration strategy that works for you. Here’s how to know if sweat testing could benefit you:

• You struggle in hot conditions or experience performance drops in heat

• You see white, salty marks on your skin or gear after a workout

• You deal with cramps or GI issues during long races, especially later on

• You crave salty snacks mid-workout

• You’re a high-sweater, with soaked clothes or significant weight loss after training

What’s the Process Like?

No workout required—this is all about sweat science, not breaking a sweat. Here’s what to expect:

1. Sweat Activation (Pilocarpine Iontophoresis): We perform a test to get your forearm sweating—no pain, just a bit of science magic to stimulate sweat production in about 5 minutes.

2. Sweat Collection: We gather a sample of your sweat via a patch strapped to your arm. This takes about 5–20 minutes.

3. Sample Analysis: There’s a blue dye in the sweat collector so we can clearly see your sample. If you notice a needle, don’t worry—it’s just used to help move your sample through the tubing for analysis.We’ll push your sweat through the sweat analyzer, run a quick calculation, and boom- you’ll have your sweat sodium concentration

4. Hydration Plan: With your sweat sodium concentration, we will discuss how to put it into practice with discussion around pre-, during- and post- training and race day. 

What to Expect

Plan to hang with us for about 30–45 minutes. While our test stimulates a small patch on your arm, you’ll get to chat with our performance dietitian about your unique hydration needs. After we get your sodium results, we’ll work with you to build a hydration plan for your next race or training cycle.

*Note: Unless otherwise agreed to, all sweat testing will take place at our Headquarters in Boulder, CO.

Follow-Up and Fine-Tuning

Your sweat test is just the start. With a personalized hydration strategy in place, we’re here to help you keep optimizing. As you train and adapt, we can revisit your plan to keep you fueled, hydrated, and ready for whatever’s next.