These days, it may seem like there’s a million different data points that you’re supposed to keep track of—hello, steps, ...

Heart rate variability (HRV) is the variation in the time between two consecutive heartbeats over a specific period. Doctors may use HRV as an indicator for certain aspects of a person’s health, ...

Most fitness trackers offer a wealth of heart-rate data. Here’s how to make sense of it. By Talya Minsberg If you wear a smartwatch or fitness tracker, you likely already have access to a steady ...