Your watch’s VO2 max isn’t perfect, but you can improve its accuracy with better data and heart-rate tracking.

VO2 max is an intimidating word for an easy-to-understand biometric: It’s how well your body uses oxygen when you push ...

Hardcore endurance athletes have tracked the metric for decades, but it is increasingly touted as a measure of fitness and ...

VO2 max measures how much oxygen your body uses during hard exercise. A higher VO2 max improves endurance and longevity. Any ...

VO2 max, the measure of how much oxygen the body consumes during exercise, has become a ubiquitous tool for professional ...

VO2 max testing requires a mask to measure oxygen intake and carbon dioxide output to determine your cardiovascular fitness. When you think about how fit you are, you might think about how far you can ...

By most measures, Norwegian triathlete Kristian Blummenfelt is the standard of peak performance in athletics. He won the gold ...

RUNNING TO THE best of your ability is something of a numbers game. To hit new PRs, you’ll want to keep tabs on all kinds of stats, like distance covered, pace per mile (or interval), max heart rate, ...