Weight as Main Measure of Health May Be Misguided
nytimes.com
nytimes.com
Summary: BMI sucks when measuring overall healthiness. A jacked-up bodybuilder could have 6% body-fat but be labeled "obese" under BMI standards.
Also, this treadmill test they're doing is a classic method used to measure someone's Vo2-Max, except for Vo2-Max you're hooked up to an apparatus and get pushed until you fail. So it's at least a pretty decent indicator of overall fitness.