I regularly do 4 hour fasted runs below or at AeT to get rid of ADS.
What do you think about speeding up due the end of such a run?
My thoughts/calculations on this are the following: Assuming I have a 400 grams Glycogen storage in all of my muscle tissue, my legs muscles (lets identify them with the muscles that do all the work when running) will account approximately to 150-200 grams of Glycogen (researched on this, lower body muscles are said to make up app. 40% of total body muscle mass) which is appr. 800 calories.
I figured that on such a long run, I burn somewhere from 500 to 600 calories per hours, which means that after 3 hours at most, the running-relevant glycogen stores are supposed to be fully depleted (assuming that I run at AeT and burn 50% of both carbohydrates and Fat). Remember it is a fasted run, so when starting, blood and liver storage sugar levels should be very low and can’t support the muscles.
What I am practically concerned with now is if, in the fourth hour, I can give everything that I have (even if heart rate goes through the roof) and still (nearly) exclusively do aerobic work? If not, where should the glucose come from? Is Gluconeogenesis relevant for such short-term needs (heard that it is only relevant for very, days-long extended fasting periods)?
When thinking about this I remembered my road-race marathon days where acceleration towards the end of the long run was a huge if not the most fundamental part of the whole training program from my coach. Why is this no part of any of the books or even here in the forum? Does this not apply to mountain athletes for any reason?
I am really looking forward to your answers!
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