What is a Sweat test?

A sweat test measures your loss of water, sodium, and potassium. We administer our sweat test In Vivo — meaning it’s performed in conditions that resemble your competition or workout environment. You’ll wear 2-3 super-absorbent fabric patches in multiple places so we can collect an optimal sample of your sweat profile. We’ll also measure your weight change and water intake after a bout of exercise. Each of these steps helps increase test accuracy, which provides you greater value. Understanding how you sweat is critical for event preparation and maximizing overall sport performance.

After your test, we remove the sample patches and take them back to our lab for analysis. Once your results are complete, we’ll send you two important measurements: your water loss rate in liters per hour (L/h) and your sodium loss rate in milligrams per liter (mg/L). You’ll also receive the less-essential potassium loss measurement in mg/L. Potassium loss is used as a control to ensure sample validity — as it’s far more consistent across different people than sodium loss.

Woman sweating and taking a sweat test

How Can a sweat test help me?

  • If you experience headaches and constant thirst after competitions or workouts, you may be hyperhydrated (too much water) and hyponatremic (not enough sodium). Getting tested and following your custom hydration plan can help resolve this.

  • Many athletes have great intent but poor execution when hydrating for an event. We’ve all heard advice from coaches and trainers along the lines of “you should start drinking a ton more water three days before your event to make sure you’re hydrated,” or “you need to carry around a gallon jug of water and drink it all every day”.

    While this advice seems healthy, in practice, it can lead to hyperhydration. When your body is hyperhydrated, especially at night, your body will prioritize correcting your water/sodium balance over sleep. You might find yourself waking up to pee many times during the night. This is a sure sign of hyperhydration.

  • If you experience cramps during or after strenuous exercise, you need a sweat test and custom hydration plan. Proper hydration can help athletes reduce cramping, even after vigorous workouts or events.

  • Do you get sore after strenuous exercise? This is due to a phenomenon called skeletal muscle microdamage, which is increased when your body has trouble regulating its temperature. Research has shown that proper hydration can increase your body’s ability to maintain an ideal temperature and thus reduce microdamage and DOMS.

  • Are you normally a kind, thoughtful person, but are known to have a dark side when the going gets tough? Do you suffer from mood swings during and after competitions? Are you a couch potato once you get home? Two studies from the University of Connecticut have shown that all of these negative characteristics can be caused by dehydration.

  • Research has shown proper hydration can maintain or improve these characteristics in various sports: reaction time, dribbling skill, decision making time, shot making, lower body agility, and more.