How sweat management may work on Apple Watch
The company’s patent (seen by Patently Apple) describes how sweat measurement could be added to a “wearable device” like the Apple Watch.
Apple’s patent explains: “Embodiments are directed to devices, systems and methods for determining a perspiration metric of a user. In some embodiments, a device may include a perspiration sensor having first and second electrodes positioned on a skin-facing exterior surface of the device. Capacitance circuitry may measure a capacitance between the electrodes, which may be used to calculate the perspiration metric. In some embodiments, the device defines a cavity such that one or both of the electrodes extend at least partially into the cavity. Other embodiments include a second perspiration sensor and measurements from the second perspiration sensor may be used in calculating the perspiration metric.”
How this feature can be useful
Studies also show that as users build physical endurance, they sweat sooner and more heavily than the average. As the body is working harder they have a higher maximum oxygen uptake. Sweat glands also get trained by fitness regimes, and become more efficient over time. This allows users to sweat more and thus remain cooler when working hard.
This feature can be used to measure fluid loss via sweat. So it can notify users when to hydrate appropriately both during and after exercise.
Apart from this, the perspiration measurement feature can be used for multiple purposes. For example, it can replace breathalyser machines that are used to conduct roadside sobriety tests. These machines measure the amount of alcohol present in water vapour, which is a replacement for blood alcohol levels.
Some medical tests which measure the concentrations of other substances in the body via sweat can also use this feature. For instance, measuring sweat chloride levels is considered the gold test for cystic fibrosis.