We have just the formula you need to sort what your heart rate training should look like.

These days, everyone from the average Susan to the hardcore data-loving wellness enthusiast has the technology to track just about anything in the name of self-optimization. A ring wearable tells you ...

For when you need to be in "zone 2" and have no idea what that is.

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 ...