Lower threshold causing need for more carbs?

Question isn’t for me. My wife finished her first sprint tri yesterday, which was quite a feat considering the abnormally high heat for the northeast and her relative lack of training (I can’t expect everyone to be as OCD about training as I am!). As an aside, I’m kicking myself for not signing up for a duathlon which I might have been pretty competitive in doing.

Anyhow, she took an SIS gel with her. I had said to her, as well as one of the race organizers giving a brief clinic to newbies, that we should have more than enough onboard to not need to fuel for a sprint event. However, she felt like she could have used another gel at some point. Which got me thinking, do people with lower thresholds go through carbs more quickly because they are more likely to go threshold or over in a race scenario? Or is it that newer people with less training are confusing muscle fatigue from lack of conditioning with needing to take on additional fuel?

I’d guess the latter, and the mental boost from carbs even if you don’t really need them to fuel your effort. At a lower power output, you’re doing less work and thus should need less fuel. E.g. on an easy long ride, I may not fuel at all if it’s 90 minutes or less, but as the duration goes up, I’ll take about 200cal/hr. Long sub-/threshold efforts I’ll go upwards of 300cal/hr. The same basic principle applies: lower threshold means lower power output means lower work/calorie burn. For a one-hour effort, a properly pre-fueled athlete doesn’t physically need additional fuel, but there’s probably some kind of mental benefit.

Current studies indicate there is likely a benefit

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That’s what I had in mind. When I’m struggling through long 12+min threshold efforts, I like to take a quick swig of carb drink even though I know it’s not adding fuel at that moment, it does seem to lower RPE.

Makes sense to me! Although she took over 2hrs to do the event, I really didn’t see imagine she would need to take any gels. I think she’d like to work on endurance now that she knows how much it takes to do an event, I’m always hoping to attract a new TR user!

If it was me and the event was going to take two hours then I would have definitely take like 3 gels and maybe a bottle of carb mix. IRC lesser trainer people also have a lower capacity to store carbs in their muscles so they may require a great intake of carbs.