Most modern smartwatches offer countless insights into how our bodies perform. But what is this data really telling us about ...

VO2max is a measure of cardiovascular fitness, and many watches and fitness trackers can estimate it for you. Here's what you ...

Zone 2 training is cardio done at a steady, low intensity. It has benefits for aerobic training (so you can run faster), anaerobic training (helping you to recover faster between reps and sets, or ...