[maforbes2000]

The recent podcast on Metabolic testing was excellent. It contained so much information, but has got me thinking about it in a different way. It has thrown out some questions for me.

1) In the early part it suggested that the Crossover Point was the most important metric for training at, but later in the podcast it suggested that it should be Fatmax. For most people, these will not coincide. Is there a view as to which is the preferable HR to train at/under.

2)It made the very important distinction that a VO2max test should be tested differently to MET.
It suggested that VO2max should be short with 1 to 2 minute step ups in speed. There was no detailed description of the ideal way to carry out the MET. e.g. How long/what intensity for warmup?, how long for each step up? what are the recommended speeds for each step up? etc I don’t suppose Dr Sickle’s MET protocol is available?

3)The MET should be carried out fasted. If a runner does not train fasted, can the Fatmax be different to the MET results?

4)It made the point about training to be good at both burning fat and carbs. Presumably this meant that speedwork is essential (is there another way to train to burn carbs)?

5) The eat fat to burn fat has always been something that I have found unconvincing. If you train in the fat burning zone, will fat burning not be improved, even though the diet is not low carb?

Many thanks for an excellent podcast.

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[Dada]

Dada on March 9, 2021 at 7:27 am #51770

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[russes011]

russes011 on March 16, 2021 at 10:00 am #52081

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[AshRick]

AshRick on March 16, 2021 at 10:14 am #52082

Sometimes lost in the quest for better fat-burning is the improvement in glucose-burning that develops. The initial fast anaerobic “burn” of the glucose molecule doesn’t produce a lot of energy — 2 ATP. But the byproduct — pyruvate — can shuttle into the mitochondria and loop into the Krebs cycle. Where it then becomes basically rocket fuel — 30+ more ATPs.

So, long aerobic running hours don’t just increase fat burning capabilities. Those miles also build up the shuttling mechanism to clear pyruvate out of the cell and into the mitochondria. That is a powerful energy source. An order of magnitude more energy from each CHO molecule.

Bottom line…we get better at both fat and CHO metabolism.

[Thomas Summer, MD]

Thomas Summer, MD on March 17, 2021 at 3:34 am #52112

1) preferable HR will depend on the individual metabolic parameters and the goals of the athlete.

2) Warmup 15-20min with very low intensity. Each step should be at least 3min. Most protocols use steps between 3 and 5min. It’s important to have the same gradient throughout and also the same increase in speed on each step, to compare it with following tests. By UA an increase in 5pbm HR on each stage is recommended as a target. But that will also depend on the specific protocol of the lab.

3) good question. If a runner does not train fasted then Fatmax is probably lower in training, because of sooner and more carb burning

4) as AshRick describes. But “speedwork” is also important to train the glycolytic (carb-burning) enzymes. But the training will depend on the specific goals

5) if you train in the “fat-burning zone”, fat burning will be improved, also if you have a diet high in carbs. But if you train in a state with low glycogen availability, then your fat burning will be improved even more. There are different ways to achieve that and it’s always depending on the individual athlete and the goals. Fuel for the work required!

I hope that helps!?

P.S. is it allowed to eat gummy bears while writing this?;-) …But I have to do some heavy strength training now. …fuel for the work required;-)