What is core sleep is on your Apple Watch, and does it even matter? We look at which sleep stages matter most for quality ...

Apple’s sleep charts can feel like a nightly report card, and “core sleep” often ends up in the spotlight. Yet the science behind wearables suggests that fixating on that one stage is a distraction ...

If you use a third-party sleep tracker with your Apple Watch, you’re probably familiar with the concept of a sleep score: an index that combines signals like heart rate variation and sleep stages, to ...

Unveiled at the "Awe Dropping" event, Sleep Score isn't an Apple Watch Series 11 exclusive. Here's a look at how it works and how to try it yourself. Apple has been taking sleep tracking more ...