Apply GSSI sports science to your
workouts with Gx Teams


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you get the most out of sweat
testing with Gx Teams.

Gx Teams Quick Start Guide

Familiarize yourself with the Gx Teams App with this downloadable Quick Start Guide.

Hydration, Performance

Sweat Testing Guide

View best practices and required conditions for sweat testing with this step-by-step guide.

Hydration, Performance

Gx Teams Overview Sheet

Get a comprehensive overview of how the Gx Teams app works, and how it can benefit you and your athletes.

Hydration, Performance
Gx Sweat Patch

Get more from team
workouts with the Gx
Sweat Patch.


Help your athletes understand the
impact of proper hydration.

Create unique sweat profiles, identify higher-need athletes, generate science-backed
recommendations, and more with the all-new Gx Sweat Patch.

See how it works

Gx Teams is for sports practitioners. It allows practitioners to help athletes understand their sweat rate and sodium losses via the Gx Sweat Patch technology, create teams to better track your roster of athletes who have unique sweat profiles, and help maintain the proper hydration of the team through personalized hydration recommendations. In Gx Teams one phone and/or app can scan patches for multiple athletes (i.e. one phone, multiple athletes).

Gx is for athletes. It allows them to better know how to train, prepare, and recover, track their fatigue and training load, and gives them weekly insights to help them improve. It’s fully customizable, and syncs with other apps your athletes might be using like Strava and Apple Health.

Both Gx Teams and Gx work together to leverage GSSI sports science and technology, and give you and your athletes direct access to the sharpest recommendations and the most effective products.

Yes! Sports performance professionals can scan athlete Sweat Patches using the Gx Teams app to generate hydration recommendations for current and future workouts. Athletes with iPhones can also perform Sweat Patch scans using the Gx app and share their sweat profiles with their teams by syncing their Gx profiles with Gx Teams.

Not yet! Gx and Gx Teams are both currently only available on iOS. You may want to give athletes with Android phones a personal nudge to hydrate before practice, since they won’t be able to receive push notifications like iOS users.

As we continue to test and develop the apps, we’re planning the best ways to launch them on Android and other platforms with even more robust features. Your feedback helps us create better tools for athletes and sports performance professionals around the world.

Sweat testing is a set of measurements to determine two things: 1) the amount of sweat lost during exercise and 2) the composition of sweat during exercise. Traditionally, sweat losses are measured through a fluid balance assessment consisting of pre- and post-exercise body mass measurements, food and fluid intake tracking, and urine and stool output tracking. Sweat composition or sweat sodium concentration is measured from a sample of sweat obtained from a sweat patch. Sweating rate and rate of sweat sodium loss are then calculated from these measurements to create a sweat profile. These measurements and calculations can help create awareness and educate athletes about their individual fluid and sodium needs along with replacement strategies. These replacement strategies may help promote optimal performance and recovery. Sweat testing may be of particular interest for those athletes who have greater fluid/sodium losses from sweat or for those who experience exercise-induced muscle cramping.

A sweat test can often be mistaken as being like a fingerprint in thinking that an athlete’s sweat rate and sweat sodium concentration do not change. However, several different sweat profiles can be generated for one athlete. This is because sweat rates and sweat sodium concentrations are not static but can change depending upon the sport/activity, temperature, humidity, intensity, clothing/equipment, training status, and heat acclimation. The sweat profile obtained can only be matched up to those conditions in which it was measured. Based on that profile and duration, hydration recommendations during and after the activity can therefore be made.

Specifically, if you are trying to obtain a game/competition/match sweat profile, we advise you to measure your sweat profile during a practice/training session that most closely mimics the conditions of the game/competition/match for that particular sport including temperature, humidity, intensity, and clothing/equipment.

Sweat rate is the amount that athletes sweat (mL) over the course of an hour. This informs their hydration and sodium recommendations throughout the course of your team workouts.

As athletes work out, they lose sodium through sweat. The amount they lose depends on their individual sweat rate and sodium concentration. The estimated sodium losses calculated by the Gx algorithm help create personalized recommendations tailored to your individual athletes’ needs.

Every athlete is different, and there is a wide range of sweat rates between athletes. Personalized hydration allows for athletes to better understand their personal needs to stay appropriately hydrated (avoid significant dehydration or overhydration) and to perform their best. Multiple national sports medicine organizations (ACSM, NATA) and expert panels have published guidelines around the importance of individualized sweat testing. For example, the most recent NATA guidelines published on fluid replacement states that athletes should “Quantify sweat rates during exercise in various environments. Develop fluid-replacement practices that promote sufficient but not excessive hydration before, during, and after physical activity.”

The Gx Sweat Patch is a first-to-market, single-use wearable that unlocks athletes’ unique sweat profiles to inform their hydration strategies and help drive performance. Athletes fill the patch with sweat during an athletic occasion and scan within the Gx and Gx Teams app, which creates their custom sweat profile and enables customized sports hydration recommendations.

When worn on an athlete’s inner left forearm during a workout, the Gx Sweat Patch will collect the sweat and route it through two channels that use non-toxic colored dyes to visually bring their results to life. Once athletes are finished working out, you scan their Gx Sweat Patch for them with Gx Teams, or they can scan the patch themselves using their Gx app. Gatorade has developed a proprietary algorithm that calculates an athlete’s individual sweat rate and sodium loss based on the color and volume of sweat that has filled the patch. We recommend scanning before the patch is completely full to get the most accurate results.

For accurate results it is important that users follow instructions for patch use.

  • The patch should be placed on the inner left forearm, approximately 2-3 inches below the elbow crease. The patch should be oriented so that the Gx logo is right side up from the wearer’s perspective (i.e. the Gx is readable to the athlete when looking at their forearm).
  • For adequate adhesion of the patch to the skin, it is critical that the skin is clean, free of skin-care products (lotions, sunscreen, spray tan, etc.), and dry before device application. Pressure should be applied for roughly 10 seconds to ensure adequate adhesion.
  • While we successfully tested athletes in the field without having to shave the patch site, it is prudent for individuals with dense hair on their inner left forearm to shave the area before patch application.
  • While wearing the patch, the user is instructed to avoid applying pressure to the patch (e.g., from towel drying the skin) or peeling the patch from the skin (e.g., contact sports), which could lead to scan failures.
  • Monitor the patch during exercise and take an image before the orange channel fills completely. The patch could overflow if worn for a long duration or the wearer has a high sweat rate (e.g., high intensity exercise in warm weather).
  • Orange dye may linger on the skin following testing. This is non-toxic food dye.

The patch does not need to fill entirely in order to get a result, but some color will need to be present.

The patch and the algorithms developed by the Gatorade Sports Science Institute are designed to be worn on one specific location—the inner left forearm. The algorithm that determines sweat rate depends on a local to whole body ratio, which is unique to the forearm. If an athlete puts the patch anywhere but the middle of their inner left arm, or if they place it with the logo facing away from them, the results will not be valid. Even if they fill the patch, their test results will not be correct or scientifically valid.

Do not try to put it back on. If the patch falls off, simply apply another one and try the sweat test again. The patch falling off could be caused by insufficient cleansing of the arm before adhesion, not allowing the area to dry completely, not applying enough force when placing the patch on the arm, or direct contact with another athlete.

If you can’t see either channel filling (orange or purple), the athlete most likely needs to work out longer or at a higher intensity. If they’ve been exercising for over 90 minutes and still haven’t filled the patch, they most likely have a very low sweat rate. You will not be able to get a result from a Gx Sweat Patch which hasn’t filled at all—at least some orange color must be present. If you think the athlete might have a lower sweat rate, be sure to plan a sweat test around a longer, higher intensity workout.

You may receive an error for various reasons. The most likely is that a Gx Sweat Patch did not capture enough sweat during a workout to register a result. If that is the case, plan your sweat test for a longer, higher intensity workout.

Another reason may be that the lighting conditions are poor when you scan the Gx Sweat Patch. Move to an area with bright, preferably natural light when scanning the Gx Sweat Patch with the Gx app. Try to ensure that there are no shadows over the patch when you scan it.

Lastly, the Gx Sweat Patch and our algorithms were developed for basketball, cycling, fitness workouts, football, lacrosse, running, soccer, and tennis with a duration between 30-120 minutes in weather conditions from 47°F to 100°F. Conditions outside of this may not produce a valid sweat result, or may produce a result with a larger margin of error.

If your athletes compete in various environments (e.g., cooler and warmer weather, indoors and outdoors, etc.), we suggest testing them during a high-intensity training session in each of those conditions in order to create a solid hydration plan for all of their most frequent competitions.

For example, you may want a sweat profile for a high intensity, high heat workout, and another for a high intensity, low heat workout.

Since athletes will likely sweat more in hotter conditions and less in cooler conditions, having a sweat profile for most competition conditions provides your athlete with their own personalized sweat and sodium ranges and gives you the ability to tailor their nutrition and hydration strategies more dynamically.

Gx Teams allows you to test your athletes much more easily and efficiently than a traditional sweat test. There is no limit on the number of athletes that can be on your team roster, and as such no limit on the number of athletes you can test at one time.

We recommend athletes download the Gx app for iPhone and sync with Gx Teams to scan their Sweat Patches themselves immediately after a workout.

The Gx Sweat Patch pairs Gatorade's innovative technology with GSSI's proven sports science knowledge. Compared to a traditional sweat test, it requires less time and effort to gain directional feedback on an athlete’s hydration needs, and does so at no more than a ±19% average margin of error. Our algorithm always places athletes in an appropriate needs category, ensuring that an accurate baseline can more easily be established, and that coaches and trainers can routinely follow up with them more efficiently.

Athletes with matching sweat profiles from previous sweat tests and workouts are assigned to needs groups prior to your workout, allowing you to predict and compare their unique sweat rates at scale and better prepare to support them. There is not, however, currently a function within Gx Teams to compare individual athletes’ test results with each other and over time.

Not yet. In order for athletes to scan the Gx Sweat Patch, the phone’s camera must be used. Apple’s watchOS does not yet have the capability of capturing an image with the watch.

Gx Sweat Patches do not contain any animal-derived products, and do not contain any latex, acrylate or methacrylate, nor are any of these materials used in the manufacturing process. In particular, the skin adhesive is certified hypoallergenic. Although the materials that comprise the Gx Sweat Patch itself are vegan, we cannot guarantee that no animal products or latex-based products were used in the manufacture of the materials that go into building it. For example, someone may have worn latex gloves during the manufacture of one of the layers of the laminate.

Pre-workout recommendations are calculated based on an athlete’s body weight and a one hour time frame leading up to the start time.

Mid-workout recommendations, depending on the information available (biological sex, body weight, exercise duration, air temperature, type of activity, energy expenditure, and Gx patch sweat rate), are calculated using our algorithm. This algorithm uses a 7-factor model to predict each Gx Sweat Patch’s local forearm sweat into a Whole-Body Sweat Rate (WBSR).

Whole-Body Sweat Sodium Concentration (WBSC) is similarly predicted using a model based on local sweat sodium concentration. We then use WBSRs and WBSCs in a sweat profile matching algorithm to predict how much fluid and sodium an athlete will lose during an activity of given length and intensity.

For example, if an athlete’s WBSR is 1,500 mL/h and their workout is 2 hours, a matched workout estimates 3,000 mL lost (1,500 mL * 2 h). If that same athlete’s WBSC is 1,000 mg/L, we estimate 3,000 mg of sodium lost for that exercise (1,000 mg x 3,000 mL).

Post-workout recommendations are calculated based on weigh-in/out values or expected sweat and sodium loss based on a matching sweat profile.

Note that generally some athletes may need gut training to reach the upper end of the recommended range for fluid intake, and should generally drink to their own comfort level. Similar to training for competition and gradually increasing an athlete’s workload, we recommend slowly increasing the amount of fluid and carbohydrates they consume during practice and games until they are in their target range.

Gx Teams can automatically send summaries of your workout and an athlete’s hydration recommendations to them via email. Athletes who use the Gx app and opt to sync with Gx Teams can also receive push notifications directly to their device. These options are available in the Notifications page of Settings.

We don’t display past workouts or hydration recommendations because an athlete’s hydration recommendations for one workout may not apply to the next—even if the two are very similar—due the complexity of our algorithm. For more accurate and safer results, we encourage you to treat each workout as a unique event.

If your athletes are regularly performing the same workout, you can schedule recurring workouts in the app and use hydration recommendations for athletes with matching sweat profiles ahead of time.

Gx Teams currently supports basketball, cycling, fitness workouts, football, lacrosse, running, soccer, and tennis. We’ve rigorously tested our Gx Sweat Patches to ensure they generate statistically valid results and reliable hydration recommendations from sport to sport, and are planning to expand into new arenas in the near future. Beyond sports, Gx Teams also supports conditioning for sweat testing purposes.

Projected intensity is one of the main contributing factors in sweat rate and sodium concentration for individual athletes and between athletes. The Gx algorithm requires this information in order to accurately calculate an athlete’s losses, and therefore make personalized hydration recommendations. As the intensity of exercise increases or decreases, so will an athlete’s fluid and sodium losses.

Gx Teams defines “conditioning” as HIIT-style training that focuses on a mix of cardiovascular and muscular strength, executed in intervals with short breaks between each.

How much an athlete sweats or how salty their sweat is will differ among varying temperatures. Knowing this information enables Gx Teams to make the most accurate hydration recommendations for your team. Environmental conditions (e.g. temperature and location) are one of the main intra/inter-individual variables in individual sweat rate and sweat sodium concentration during exercise.

Zip codes help evaluate the weather during scheduled outdoor workouts. This enables the Gx algorithm to make the most accurate and personalized hydration recommendations for your team.

Several important input factors are used in the model that predicts an athlete’s whole body sweat rate (WBSR); these include biological sex, weight, air temperature, exercise duration, Gx patch sweat rate, activity type, and energy expenditure. Removing input factors limits the app’s ability to provide accurate WBSR results. Based on our statistical modeling analyses, activity type (i.e. using Gx patch during an unvalidated sport or activity) and energy expenditure may be removed and still produce WBSR results. However, by removing one (or both) of these factors, the margin of error surrounding the predicted WBSR grows. This impacts the accuracy of fluid intake recommendations and increases the risk of overhydration or dehydration. Therefore, we recommend using the patch only during validated sports and activities and providing an energy expenditure (through a wearable) to maximize the applicability and accuracy of all hydration and nutrition recommendations. GSSI is continuing to conduct testing with the Gx Sweat Patch to expand the list of validated sports.