If you wear a fitness tracker, you've likely seen a stat labeled "HRV" pop up on your screen. But what does it mean, and does it matter? Short for heart rate variability, HRV has become a popular ...

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 ...

A recent study showed that the heart rate variability of a dog and its owner adapt to each other during interaction. High heart rate variability is associated with relaxation, while low heart rate ...