That tension becomes especially clear with heart rate zone training, a popular five-tier system that endurance athletes use to measure effort and fine-tune performance. The well-known formula is ...

Heart rate variability (HRV) is the variation in the time between two consecutive heartbeats over a specific period. Doctors may use HRV as an indicator for certain aspects of a person’s health, ...

Whoop is a top fitness and health tracker – and one of my favorite devices at Wareable. But if you want to check your heart rate, it can be a little hard to find. I’ve been using Whoop for years – so ...