One of the biggest new features that has come to wearables over the past couple of years is heart rate variability (HRV) tracking, and using this to gauge the stress on your body and how ready it is to exercise.
The Oura ring was the first device I tested to really make this “readiness” measurement useful, tracking your HRV overnight and using it, along with other factors, to give a readiness score every morning so you can judge if you should do a hard workout. It’s also used across many of the best sports watches, especially high-end models from Garmin, with its training readiness score tying together lots of activity and recovery stats, including HRV.
