Fitness trackers and smart watches are widely popular wearable devices that measure several types of health metrics, including step count, calories burned, sleep quality, Vo2 max and heart rate. As a ...

We know the beat of our heart varies over time, increasing with exertion and slowing with rest or meditation. But, stable as those variations may appear, they vary even within those intervals. Dr.

These days, it may seem like there’s a million different data points that you’re supposed to keep track of—hello, steps, sleep, and recovery scores!—and it’s difficult to know which ones are worth ...