ali
Level 7 Valued Member
I currently have lots of time ; )
And all the better we are for that! Lots of morsels in there to chew over.
Hoping that you could answer a couple of related questions Mike, please?
Is there a difference in energy usage comparing aerobic and anaerobic substrates? So at high and very high intensities the anaerobic system is ripping up the glucose.....does that imply that the revved up aerobic system is preferentially using pyruvate for the Krebs cycle?
At the 40% VO2 Max point on the graph, fat and carbs are equal, as intensity increases, energy is supplied more by carbs.....is that due to more anaerobic influence or due to more glucose being made available for use and thus will be used aerobically too? That glucose being made available by the dump of hormones, ready for action.
It's known that trained endurance athletes can utilise more fat at higher intensities than those untrained, or less trained, so the implication of that is fat is being used in the Krebs cycle whilst additional anaerobic input supplied by glucose and an efficient lactate shuttle. I get that. But when carb usage is so high, those carbs must also being burned for mitochondrial ATP too, at some point?
So if looking to be metabolically flexible.....being able to switch aerobic fuel to and from carbs to fat and vice versa.....can this switch occur quickly or is it due to the duration and intensity? Can both pyruvate and fatty acids be prepped to enter the Krebs cycle at the same time?
Hope I'm making sort sort of sense to you....many thanks