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.

Discover how smart rings 2026 track sleep, HRV, and fitness metrics. Compare Oura Ring 4, accuracy rates, battery life, and ...

A few of the most important insights are heart rate variability (HRV), which describes the difference in time between the beats of your heart, and resting heart rate (RHR), which is the number of ...

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 ...

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 ...

The rhythm of a healthy heart may seem steady, but underneath that regular thump lies a rich, ever-changing pattern. These beat-to-beat changes, known as heart rate variability, or HRV, reveal much ...

Respiratory rate, another metric in the Apple Watch vitals app, shows how many breaths you take per minute. This typically ...