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 ...

Beth Skwarecki is Lifehacker’s Senior Health Editor, and holds certifications as a personal trainer and weightlifting coach. She has been writing about health for over 10 years. Whoop, the screenless ...