Forward-looking: While the health-monitoring abilities of wearables have advanced enormously in recent years, there's one thing that still eludes these devices: measuring glucose levels, aka blood sugar. The prototype ring they created uses sweat to track chemical biomarkers. In addition to glucose, the ring can monitor ketones, vitamin C, uric acid, lactate, and alcohol concentrations. We've been hearing stories for years now about an upcoming Apple Watch that can measure glucose, but it's yet to happen. Electrochemical sensors in the smart ring repeatedly analyze the sweat, using the readings to calibrate the device and calculate concentration levels.