Having just looked at , A Novel Method to Predict Carbohydrate and Energy Expenditure During Endurance Exercise Using Measures of Training Load | Sports Medicine , linked from intervals.icu utilisation of CHO [ carbohydrate] during exercise , it strikes me that TR [ trainer road ] ,given that it has all our exercise histories , could do some pre-processing and give an approximation of how much CHO you are likely to utilise during any given workout. This could help with fueling strategies . What do you think ?
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Yes that’s absolutely right. However I’ve asked ,and I think it is, is it possible to predict utilisation beforehand. With the view I suppose of getting the fueling strategy correct. Having said that I think it would be almost impossible to take in too much CHO whilst on the bike. So it’s really a moot point.
I think you can approximate it with some math:
FTP * IF * Duration in seconds / 1000 = kJ
FTP of 300
IF of 0.7
Workout = 75 minutes
300 * 0.7 * 4500 / 1000 = 945 kJ
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Yes this seems a reasonable approximation of the total energy expenditure. Trainerroad already predicts this . My question was : is it possible to predict the CHO that is going to be utilised during a given session. Obviously this is going to be a fraction of the total energy expenditure. The paper that I cited does include a method.
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Have you looked at something like hexis.live
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Xert attempts to estimate fat and carbohydrate oxidation, not just kJ. It may be worth a look if you’re interested. Is it correct? I don’t know.
Here’s an example:
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I’m not sure that’s even possible beyond ballpark estimates.
If I may ask, why do you want this? Is the idea that if your body “only” uses carbs for 80 % of the energy expended, then you will replenish only those 80 %? Or would you scale up your fat intake as a result?
Generally speaking, there are a few facts that we have to contend with:
- Most normies (≠pros) can expend more energy during endurance workouts than they can take in per hour. There are some exceptions, but from memory, about 150 W average is enough so that your energy expenditure exceeds what you can take in at 90 g/h.
- Weight is determined by whether you are energy deficit or energy surplus. The energy source is less important.
- The most common suggestion I have heard for cyclists is to set goals for protein and fat (typically in grams per kilogram of body mass or perhaps lean mass), and then “fill up with carbs”.
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+1 for asking how exactly you plan on using this information
Let’s say you burned 2000kJ on an endurance ride. Let’s say 750kJ was carbs, 1250kJ was fat. Now what?
Clearly you replace that with 1250g of fat.
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And how specific do you want to get in term of, for example, complexity of the carbs, or the type of fat?
How much pork belly do I need to eat for 11000+ calories.
I’ll give it a go. It might take two sittings.
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What do you do with this info with regards to sugar consumption on the bike?
You fuel according to intensity and duration of the workout. Although I don’t look at kJs expended, like I said, I won’t be able to replenish all calories I burn during the ride.
Nothing. I do 100+g of carbs an hour always.
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