VO2 max is often referred to as a key marker of fitness. It’s the measure of the maximal amount of oxygen your cells can take in and use during exercise. Because VO2 max is so closely tied to running ...

Until recently, VO2 max testing has been inaccessible to most everyday athletes. Unless you had an in with an exercise physiology lab, you had to rely on back-of-the-envelope calculations or wearable ...