"For the sleep obsessed, there’s a plethora of technology available designed to keep an eye on your sleep quality and habits, from wearables and sensors you place on your mattress to headbands that aim to measure brainwave activity. If you’re already using an Apple Watch or a Fitbit, you’re probably familiar with their built-in sleep tracking functionality. However, there’s a couple new companies offering wearable products that are geared more narrowly towards rest and recovery, like the Oura ring or the WHOOP band. The Whoop tries to parse out the data taken from your everyday life and break it into three categories: strain, recovery, and sleep, then gives you an overall percentage grade of readiness for more strain so that you have some feedback about whether you’re ready for a workout or should be prioritizing rest. The Ouro uses a similar system, but their tracker is a minimalist ring with sensors inside the band."