Gatorade got together with a tech company to create a wearable patch that tells you if you’re hydrated enough.
You stick this thing -- called the Gx Sweat Patch -- on your inner left arm while you’re working out.
And then, it beams your hydration -- or sweat -- info to a smartphone app that lets you know how much to drink to get your hydration levels back to normal. (Gizmodo)