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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. Howev
by trentnix 5y ago
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.
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.
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.
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.
Many years ago I did an Ironman (Couer d'Alene) and a Vo2 test indicated I needed to aggressively 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.
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.
One additional note - there are machines much less expensive than 60k available, but they are still pretty expensive (in the thousands).
- dpeck 5y agoI appreciate the modesty, but talking about completing an Ironman and having the phrase “really wasn't all that fit” anywhere near it is comical. Getting through any one of the stages of an Ironman (or heck even a half of each stage) represents a level of fitness most adults do not have and will never attain.
- trentnix 5y agoSure, but my point was really to suggest I’m just a regular guy who did an Ironman very slowly. There are physiological freaks at Ironman events, but I was certainly not one of them. Regular people with a plan and appropriate training can do it.
- moneywoes 5y agoHow much running training did you do and if you don't mind sharing what was your marathon time?
- trentnix 5y agoWhen I started I was able to run a 5k and that was about it. I trained for 21 or 22 weeks. I think my marathon was a 5:30 or something like that. Lots of walking, but I never stopped moving.
- thelittleone 5y agoRespect for achieving that in 21 weeks.
- andreskytt 5y agoNot necessarily true, I think. It’s a mental barrier more, than a physical one. Tell someone you ran 100 m in 12 seconds and they go “meh”. Tell them you did a marathon and they go “i could not do that, awesome, how could you etc.” whereas an average person can do a marathon with a years worth of training and never achieve that sprint time. It took for me 21 months of training to go from effectively zero to a half ironman and the biggest barrier was swimming, which is very technical in nature. I still can’t swim very well. I was in no shape at all and overweight. If you look at the speeds required to stay within ironman time limits, they are quite low and a person in a slightly better than average condition would be able to sustain them with relative ease. The barriers might be swimming technique (which one might have from training as a kid) and things like biking position and running technique but not necessarily fitness as such. In fact, I see quite a few people visually in much worse shape than I am (i.e. fatter) doing long IMs and beating me at shorter distances.
- ssl232 5y agoA friend of mine does keto and after running a marathon reported that they did not experience "the wall". Presumably this is because they were using fat to begin with, not after mile 15 or whatever.
- aix1 5y agoIt all has to do with intensity. We obviously can't tell from the information provided, but if they ran at a slow pace, that would also skew the fueling towards fat.
- rct42 5y agoExactly. While the marathon is an endurance event, the intensity when racing is often higher than 65% VO2 max - the "fat max" or point at which fat oxidation peaks. For example, for a 3 hour marathoner (or faster), the intensity would be around 74-84% VO2 max or 80-90% max heart rate. It has also been observed that going on keto reduces your running economy (so you end up running slower for the same effort). As for "hitting the wall", this often happens around 20 miles as this is where your stored glycogen is depleted. To avoid this happening, you'd be better off to "train the gut" to handle consuming ~60g carbs per hour while running at your target pace/intensity.
- andreareina 5y agoAIUI 60g/hr is for pure glucose, thanks to co-transport another 50% can be handled as fructose (i.e. 2:1 glucose:fructose ratio)
- texasbigdata 5y agoNot to be an idiot but you're implying 90g just to confirm the math.
- andreareina 5y agoYup
- soperj 5y agoJust a note, it's probably "Coeur d'Alene"
- trentnix 5y agoYep. Sorry for transposing a few letters. It’s a tremendously beautiful and friendly place. I’d love to go back one of these days.
- jasone 5y agoUnless you're dealing with mail, in which case you're more likely to succeed with "Coeur D Alene". Our city name apparently isn't sufficiently American in some contexts.
- gameswithgo 5y agoThe idea that fat efficiency can be improved via diet or training is often said, but the people I have known who both tried it and carefully measured it couldn’t. Also there are perfectly ordinary ways to figure out you need to eat more, Ive coached some pro cyclists and done a decent amount of my own triathlon and cycling adventures and if someone gave me a free vo2 machine I don’t think I would ever use it.
- aix1 5y agoThis is probably not exactly what you mean by diet, but Rob Gray (an Ultraman world champion) says: in the 10 days before the race I would predominantly eat a high fat diet. Based on all the testing I’ve done, what you eat in this window has a large impact on how your body uses fat vs carb on race day https://robgray.org/ironman-arizona-nutrition-report/ https://robgray.org/ironman-arizona-nutrition-report/
- danielovichdk 5y agoCarbo loading can be done prior to a race. The day before is usual. But even carbs in the morning before a race is effective. The fat burning starts when you empty the glycogen chambers, but there is a sweet spot in terms of energy output, because as other people has pointed out, you can't do high intensity work on fat. So it makes sense as an ultra endurance athlete that you try to pack som fat before a race, because it will be effective as a slow burning resource. Another interesting thing at the moment are the ketones supplements one can drink.
- danielovichdk 5y agoWhich pro cyclists have you trained ?
- nradov 5y agoWill this device actually tell you fat versus glycogen metabolism the way a real exercise lab test would? From the description it doesn't seem so. I think all it really tells you is the amount of oxygen used.
- boringg 5y agoI would say vo2 max is fairly useful but maybe not in a tactical way which you are describing. Its a longer term trend identifier for efficiency of your respiration process.
- nradov 5y agoWell sort of. But you can train VO2 Max in ways that don't result in higher performance. What most athletes really care about isn't VO2 Max per se, but rather ability to sustain a high percentage of VO2 Max for a longer period.
- panabee 5y agocould you kindly elaborate on why Vo2 max isn't useful for an athlete? naively, it seems measuring oxygen consumption would be useful.
- DrOctagon 5y agoIt’s been a while since I’ve read much about this but one explanation I’ve heard is that Vo2 was elevated to importance because it could be accurately measured and therefore studied. Also unlike aerobic fitness, which can be improved with year after year of consistent training, an athletes peak Vo2 max (for their given fitness) can be maxed out over 4 - 6 weeks of specific training. Doing much more specific Vo2 training can result the athlete (at least in running) becoming ‘flat’. That said Vo2 measurement can provide a great deal of useful information but for most recreational athletes getting the basics right is more important than having an exact Vo2 measurement.
- trentnix 5y agoIt’s not useful because it’s not really an indicator of one’s ability to perform and can’t really be affected through training. It’s primarily affected by genetics and weight. That said, it does provide some correlation to an athletes performance “ceiling”, and you’ll typically find elite endurance athletes are naturally blessed with an impressive Vo2 max. You’re not going to win the Tour de France with a Vo2 max of 50 no matter how hard you train, just like you’ll never play Center in the NBA if you’re 6’1.
- iamacyborg 5y ago> the calculation of an athlete's Vo2 max really isn't all that useful I can hear thousands of Garmin owners screaming about this comment as they obsess over their VO2 Max.