Apple is reportedly working on bringing a feature to the Apple Watch that has been noticeably absent since the wearable's inception: sleep tracking. According to a report by Bloomberg's Mark Gurman, "people familiar with the work" claim the iPhone maker has been testing a native sleep-tracking feature for its smartwatch over the past several months. Apple reportedly plans to introduce the feature by 2020, likely in a new model of the Apple Watch.

Despite tracking all-day activity, swimming, ECG, and more, the Apple Watch has never had a native sleep-tracking feature. That's been a long-time disadvantage for the wearable in comparison to some of its biggest competitors like Fitbit's Ionic and Versa smartwatches. Almost all of Fitbit's wearables track sleep, as do devices made by Garmin, Withings, and other health-tech companies.

There are Apple Watch apps that track sleep, but they're all made by third-party developers. Apple also isn't a stranger to sleep tech in general: the company bought the Finnish company Beddit in 2017 and sells its sleep-tracking mattress sensor on its website.

I've asked Apple in the past about the lack of sleep tracking on the Apple Watch. Most of the vague responses I've gotten pointed toward preserving the balance between feature set and battery life—in short, Apple doesn't want to compromise the battery life estimates for the Watch. Currently, the Apple Watch can easily last one full day on a single charge, and I've gotten almost two days of life with the Apple Watch Series 4.

But that's nothing compared to most of Fitbit's devices that track sleep, which can last five to seven days on a single charge (depending on the device). According to the Bloomberg report, Apple may accommodate a sleep-tracking feature by increasing the Watch's battery life, creating a way for sleep tracking to occur during a low-power mode, or simply requiring users to charge their Watches in the morning.

I find the latter option unlikely because those using third-party sleep tracking apps already have to do this if they want to use their Apple Watch for the entire day after tracking a night's sleep. This is the default option, so Apple could have debuted a sleep-tracking feature already if it wanted to ask this of users.

The other two options are more intriguing: Apple could try to stick a larger battery in the Watch or make other hardware components more efficient to increase battery life. It already did so in the Series 4 with the new LTPO display technology used in the Watch's screen, but those gains were offset by the increased power of the device (resulting in roughly the same estimated battery life as the Series 3).

The Apple Watch already includes a low-power mode that helps preserve battery life, and I've used it overnight numerous times when I've forgotten my charger and want to use the Watch the next day. Apple may be able to figure out how to make certain parts of the Watch work while employing low-power mode, like the accelerometer and the heart rate monitor, and use them to track sleep. Apple will want to enable the Watch to track things like time spent in various sleep stages (light, deep, and REM sleep) and time spent awake, like Fitbit's devices do. Tracking most of those metrics require the use of the heart rate monitor.

As iPhone sales slow, Apple has been looking for new ways to increase revenue in other parts of its business. Its wearable sector, which includes the Apple Watch and other devices like AirPods, has been strong the past few quarters. CEO Tim Cook has also mentioned health tech as an important part of Apple's future—undoubtably, new and expanded models of the Apple Watch will be part of those plans.