Sweat tech alerts athletes when to rehydrate — and with what

Electrolytes [Ee-LEK-troh-lytes] are a key group of minerals to track, he notes. (As their name suggests, electrolytes have the ability to carry an electric current.) Plain water rehydrates someone who’s been sweating. But Gatorade and other sports drinks do more — they also replenish important electrolytes. These may include sodium, chloride and potassium. Such minerals keep nerves, muscle and other tissues healthy. They also help control blood pressure.

Rogers has been working with Gatorade’s maker to develop the sweat sensor. Worn like an adhesive bandage, this skin patch looks simple on the outside. Inside, it’s anything but simple.

Tiny channels about the width of a human hair collect sweat. They include color-changing chemicals that react with electrolytes. The colors of this “lab on the skin” tell athletes which electrolytes they should replenish. The sensor is attached to only one spot – an arm, calf or the forehead. But it shows “what’s going on in the entire body,” Rogers says.  

He and his team described an improved version of the sweat sensor in the December 2019 Nature Communications. That patch alerts users with a skin sensation when they have lost a certain amount of sweat.

The researchers have tested the sensor in hundreds of athletes. Gatorade plans to start selling it in late 2020, says Rogers. Knowing when to get a drink— and what it should contain — will help athletes achieve their peak performance. And it will help the rest of us stay healthy when we work out.