This is really great. For those who aren't familiar with what these machines can do, the calculation of an athlete's Vo2 max really isn't all that useful. However, a breakdown of the fat and carbohydrate calories burned at various efforts can be incredibly useful for helping an athlete learn how to fuel correctly for performance over distance.<p>I'm not a physiologist or physician (and I'm sure what I'm about to say may be max cringe to the bonafide experts that are around), but my basic understanding is that when expending effort, you burn calories from fat stores and from glycogen stores. Glycogen stores store around 2000 calories, and expending one's glycogen stores results in hitting "the wall" - your body simply doesn't have any fuel to proceed. Your fat stores, on the other hand, provide access to tens of thousands of calories.<p>People are generally fat-inefficient - any effort immediately biases towards consumption of glycogen. And when you're out, that's it. Your day is done. So knowing the rate you're burning carbohydrate calories can inform an athlete how often and how much to fuel.<p>Some people are born "fat-efficient", meaning they can access their fat stores easier. Fat efficiency can also be improved through low-intensity endurance training with improved diet. So athletes will periodically do a VO2 test to stay in-tune with how their body is using the fuel sources available to it.<p>Many years ago I did an Ironman (Couer d'Alene) and a Vo2 test indicated I needed to <i>aggressively</i> consume calories (at the effort I was planning to ride) on the bike. After all, you have to get off the bike nutritionally prepared and hydrated to run a marathon. So that's what I did, and I had a good day considering I really wasn't all that fit.<p>Endurance and ultradistance events aren't really tests of toughness. They are science experiments. It's all about figuring out how to take one's fitness and stretch it over the distance of the event.<p>One additional note - there are machines much less expensive than 60k available, but they are still pretty expensive (in the thousands).