Rumors are circulating that the next Apple Watch may be monitoring blood sugar and alcohol levels, but we're not going to hold our breath. Speculation about an Apple Watch capable of measuring blood sugar first arose in May of this year, when the company began asking users what apps they use to monitor their levels. Now these rumors have been further fueled by news that one of Apple's suppliers, Rockley Photonics, has developed a wearable "wrist clinic" capable of monitoring biometrics, including core body temperature, blood pressure, hydration, blood alcohol and glucose. It's an impressive list and includes many metrics that no existing smartwatch can measure. Some watches (like the Samsung Galaxy Fit 2) can estimate blood pressure using data from their optical sensors, and many fitness trackers can measure skin temperature, but these aren't as accurate as a bracelet or thermometer. Skin temperature is affected by factors like ambient temperature and exercise, making it less reliable than a digital thermometer, and the blood pressure sensors in smartwatches need to be calibrated regularly with a cuff. Until now, no watch can even estimate blood sugar; Any smartwatch app that "tracks" your levels is simply a way to record readings from a fingerstick monitor. Doing this non-invasively would be extremely useful for people with diabetes, who currently have to measure their levels using fingerstick blood tests. People can also use a small probe that is placed just under the skin and measures glucose in the fluid around the cells, but this is still invasive and less accurate than a blood test.
How does the "portable lab" work?
While today's smartwatches shine a broad-spectrum LED onto your skin and analyze changes in reflected light, Rockley's sensor module uses numerous discrete laser outputs from a single chip. In a nutshell, this means that it can identify and assess many other biometric markers, including the properties of blood, interstitial fluids, and the different layers of the skin. However, we will have to be patient. Rockley has said he's targeting the consumer electronics market, but we highly doubt his new technology will appear in Apple Watches anytime soon.
