Plenty of fitness wearables track fundamentals like your heart rate or step count, but there's so much more to your body than that. What about your fluid levels, for example? That's where UC Berkeley might help. It developed a flexible sensor that measures the electrolytes and metabolites in your sweat, along with your skin temperature. If you need to improve your diet, a quick run might reveal the truth.
The existing system is a bit clunky thanks to its big circuit board (you currently have to wear a dorky headband or wristband), but researchers are confident that it could shrink to a single, subtler chip. You could easily slip this into an activity tracker or smartwatch, in other words. And importantly, it wouldn't be confined to measuring sweat. Eventually, this could be used to track chemical levels in any kind of bodily liquid -- if you were sick or injured, you'd get a heads-up the moment your fluids were too far out of whack.
[Image credit: Roxanne Makasdjian and Stephen McNally, UC Berkeley]