HRV is the measure of the time variation between heartbeats

What is Heart Rate Variability (HRV)?

When we think of our heart rate, we think of a number between 50 and 90 beats per minute (BPM). This number represents our average heart rate.

In reality, our heart rate changes from beat to beat. For example, when you inhale your heart beat speeds up and when you exhale it slows down. So an average heart rate of 60 BPM may actually vary between 55 and 65 BPM.

Heart Rate Variability (HRV) is a measure of this naturally occurring variation in the heart rate.  Research shows that lots of variation in the heart beat intervals, or high HRV, is a sign of health.