The Apple Watch may soon be able to track and estimate sweat from workouts

A future Apple Watch may include the capacity to measure sweat from workouts and estimate required hydration levels, with the company granted a patent detailing an all-new sensor setup.

First discovered by Patently Apple, the filing describes how a wearable device could include a perspiration sensor that automatically kicks in when a user starts exercising. 

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As we know from previous patents drawn up by Apple related to sweat sensing, it potentially sees this as an avenue to improve both its fitness tracking and health monitoring. 

By measuring perspiration, it's able to not only inform rehydration levels from those who have been on a run, but perhaps also notify a user when they're dehydrated from extreme heat, for example.

It could even potentially be leveraged to detect overhydration, too, though none of this is explicitly mentioned in this latest patent. 

Patently Apple

Instead, there's plenty of the typical patent mumbo-jumbo relating to the inner workings of the sensors picking up on a wearer's sweat output.

Cutting through some of this, Patently Apple suggests that the sensor could be configured to measure from two different points, with this data then turned into an estimated sweat rate metric.

"When Apple Watch is used to track an exercise session, the device may calculate and present a first estimated sweat rate over a first interval of time corresponding to the exercise session. This may provide a user with information about the average sweat rate or total fluid loss over the course of the exercise session," the report reads.

This would prove an invaluable tool to those with fuelling and hydration plans on race days, for example, with the patent outlining that the Apple Watch may be able to provide a real-time estimation of how much sweat a user is likely to lose through a specific activity.

So, when could we actually see something like this arrive on a future Apple Watch?

As with most patents, we're unlikely to ever see this specific technology included in an upcoming device. However, we do think it's relatively likely that sweat tracking from the Apple Watch is likely to arrive at some stage in the near future. 

We think Apple has its sights set on different health insights for the Apple Watch X, but don't rule it out for a 2025 version of the smartwatch just yet.