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.

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 ...

Heart rate variability during sleep can predict stroke, depression or cognitive dysfunction years in advance, according to new research presented at the European Academy of Neurology Congress. The ...

Whether due to stress or an intense cardio workout, most of us have felt our heart racing from time to time. A rise in your heart rate can be perfectly normal given outside circumstances. However, ...