The Apple Watch Series 4 is an incredibly capable health and fitness tracker, but there's one area where Apple's smartwatch lags behind Fitbit and other fitness trackers – sleep tracking.
Yes, while you can track your sleep using third-party apps, unbelievably, the feature isn’t baked into watchOS.
That looks set to change, however, as Apple has been secretly testing a sleep tracking feature.
According to Bloomberg, who has spoken to “people familiar with the work”, Apple has been working on the feature for months now and plans to add it to the Apple Watch by 2020.
One reason we haven’t seen sleep tracking on the Apple Watch is probably to do with battery life. While fitness trackers can last several days or weeks in between charges, the Apple Watch generally needs nightly charging.
That's slightly inconvenient if you also want to use it to track your sleep.
It's not yet clear if this will be exclusive to a new Apple Watch model, or if it will added to all existing models with a software update.
Theoretically, all you need for sleep tracking is an accelerometer and a heart rate sensor, so previous Apple Watch models should be capable of this new feature, but if Apple is waiting until 2020, it could be because new models have a longer battery life and as a result will be able to last longer in between charges.
Of course, it's completely possibly that this feature will never see the light of day – Apple must test dozens of features that never make it to its customers. However, if I was betting man, I'd put money on sleep tracking coming to the Apple Watch. It's a glaring commission in it's health and wellness arsenal.