Apple has been researching ways to have an Apple Watch band automatically track the wearer's hydration for years, with all the benefits that health monitoring would bring. Now there are new details.
Apple supplier Rockley Photonics recently announced a non-invasive glucose monitoring system that appeared to be intended for the Apple Watch, as the demo units use Apple wristbands. Conveniently, however, this announcement overlooked the fact that Rockley's system is designed to monitor much more, including hydration. Now, Apple has separately received a patent addressing just that: a patent for a hydration sensor in the Apple Watch. As the newly revealed study, "Hydration Measurement with a Watch," shows, hydration is an important health indicator. It's one that can contribute a vast amount of information from a single type of sensor. The patent states:
A user's hydration level has a significant impact on their health. Dehydration can impair performance and is associated with several adverse health consequences, including heat stroke. Excessive drinking can lead to hyponatremia, fatigue, confusion, coma, and even death.
There are currently many apps for iPhone and Apple Watch designed to remind users to drink often and not too much. However, when it comes to actual measurement, the patent states that typical techniques are "generally invasive, expensive, or unreliable." Apple further states in the patent:
Will future Apple Watch straps be equipped with sensors?
For example, some techniques for tracking hydration involve testing fluid samples, such as urine or blood, from the user. Some techniques require analytical sensors that chemically react with the sample fluids. Many of these sensors are disposable and limited to one-time use. However, other techniques involve tracking fluid intake, fluid excretion (e.g. sweat, urine, etc.), and weight changes over a period of time.
Apple's patent is even somewhat dismissive of what it describes as these "cumbersome and unreliable" techniques. The patent's original inventor, Alexander W. Williams, also points out that the lack of reliability is primarily due to the "multiplicity of measurements that must be taken manually." His suggestion is that the Apple Watch instead take regular, periodic measurements to calculate a user's hydration using a watch band.
A watch band can be positioned to receive and measure one or more electrical properties of the sweat produced by the user wearing the watch. The measurements can be used to provide a user with useful feedback and health tracking information, allowing the user to better manage hydration and overall health.
Measure hydration levels non-invasively
Apple's idea is to incorporate electrodes to measure the electrical properties of sweat. These properties can represent a concentration of electrolytes in the sweat, which in turn represents the user's hydration level. Because this measurement is performed on sweat, it is non-invasive and can be performed repeatedly, accurately, automatically, and with minimal user intervention. The measurements can then be tracked over time, "allowing the user to better manage hydration and overall health." This patent was only recently revealed, as it was just granted—but a version was originally filed in March 2018. Whether we'll ever see such a product remains to be seen, of course. Patent applications often offer fascinating insights into Apple's current research and development areas. In the end, however, they may remain just an idea. Don't have an Apple Watch yet? The models currently range in price from 129 and 1704 euros. (Photo by hadrian / Bigstockphoto)
