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 ...

Exercising at your max heart rate might leave you drenched in sweat, but that doesn’t mean it’s something you should do regularly. In fact, spending too much time in the high zone could cause symptoms ...

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 ...