Deep sleep is one of the most essential stages of the sleep cycle, playing a vital role in how well you feel both physically and mentally. Often referred to as slow-wave sleep or delta sleep, this ...

Smartwatch makers promise to turn your wrist into a sleep lab, translating tiny movements and heart rate blips into colorful ...

Now that we have wearables tracking our every move, a lot of us can look at stats that supposedly tell us how well we’ve slept the night before. But sometimes, it can feel like your sleep tracker is ...

Let's talk about one of the most confusing terms you’ll see on your fitness tracker—specifically your Apple Watch. Next to REM sleep, which you’ve probably heard of, and “deep” sleep, which feels self ...