Heart rate variability is now a common smart watch fitness stat. What does it mean for your exercise load?
As the popularity of smartwatches, also called wearables, increases, so too does the amount of data users can access about their health. Statistics like resting heart rate, V02 max (maximal oxygen consumption) and heart rate variability (HRV) provide valuable insight into your fitness levels. But not all measurements are created equal. While HRV has long…