Wearable patch works with an app to tell if you are hydrated

Not taking enough fluids and becoming dehydrated can cause physical problems and ailments in people from all walks of life. PepsiCo is rolling out a new product this week called the Gx Sweat Patch. It comes from a startup called Epicore Biosystems that's working with PepsiCo subsidiary Gatorade. The wearable patch measures the rate of perspiration and sodium chloride concentration in that sweat.

The patch tracks sweat loss during activity along with heat stress to use the information to recommend how much and how often athletes should drink to replace fluids lost. The goal is to help athletes avoid dehydration and impaired performance. The patch has some potential uses in the future, including the ability to help athletes determine an optimal diet and sleep pattern.

The wearable microfluidic patch goes on sale today at sporting good stores and online, priced at $24.99 for a pack of two. The new product is the first time Gatorade has moved into the digital products and app realm for athletes. Epicore's wearable patches have been in testing with athletes for a while. The patch routes sweat through microfluidic channels cut into stacks of thin-film polymers.

One of the microchannels tracks sweat rate and volume excreted, dyeing the sweat orange to make it visible as it moves through pathways in the patch. The other microfluidic channel has reagents that react with chloride in the sweat, turning purple with the intensity of the purple color corresponding with the concentration of chlorine ions detected.

The patch is worn on the left inner forearm during a workout, and the user scans the patch using their smartphone. The Gx app uses the image with data the user inputs on weight, sex, workout type, and the environment to create a "sweat profile" and make recommendations about fluid intake.