Physiological benefits of "lactate clearance" training?

[frenchyge]

Who is telling you to improve lactate clearance?
It seems simple enough to as them what the rationale behind this is.

I agree. I don't believe I've seen many advocates of lactate clearance training here. Maybe the OP is confusing Andy's recent comments that lactate clearance affects the shape of one's lactate curve as a recommendation that lactate clearance should become a training objective.

If I read this correctly, the author of this paper endorses a testing methodology that Guy Thibault calls an unscrupulous way to for sports scientists to earn money, i.e. lactate threshold ramp tests == snake oil.

Maybe he does, I wouldn't know. I gleaned the free information that seemed helpful to my understanding, and rejected the information that seemed unhelpful or not useful. I'm also not sure when those articles were written, so it's possible that what was considered the body of knowledge at the time may appear to be snake oil of some type based on discoveries that have happened since.

 

[HammerHead]

Maybe I totally understand this wrong, but isn't lactate a metabolic intermediate, resulting from anaerobic conditions. O2 runs out and the electrons can't run their normal metabolic course, and your left with lactate. Sure it is an energy source, but I would think a less attractive one since (going off of memory and what I've read here) it needs additional metabolic attention before it is used (matabolized to pyruvate). There is surely an energy cost to that. And if acidic conditions are not ideal, wouldn't production of lactate either contribute to or indicate low pH (proxy?). So maybe clearing lactate aids in improving pH conditions?

 

[WarrenG]

If I read this correctly, the author of this paper endorses a testing methodology that Guy Thibault calls an unscrupulous way to for sports scientists to earn money, i.e. lactate threshold ramp tests == snake oil.

How odd, considering Guy Thibault wrote an instruction manual for the Canadian Cycling Association in 2002 that includes blood lactate measurements at the end of each step of the load.

http://72.14.203.104/search?q=cache...e+test&hl=en&gl=us&ct=clnk&cd=1&client=safari

Two excerpts...

"During the last seconds of each 3-minute level, take a blood sample according to the
manufacturer's instructions and keep the sample to analyze the blood lactate level..."

"Step 16

Fill the form for gathering test results after having done the necessary calculations,
such as those that estimate the maximal oxygen uptake in L/min and in mL/kg/min.
Give the athlete a copy along with a graph representing the heart rate and blood
lactate level (BLL) evolution, according to the power output in Watts, specifying the
heart rate zones, corresponding to intensity ranges like 95-100 % MAP, 90-95 %
MAP, 85-90 % MAP, 80-85 % MAP, 75-80 % MAP, etc. an those corresponding to
blood lactate levels of 2 and 4 mmol/L."

 

[SolarEnergy]

it needs additional metabolic attention before it is used (matabolized to pyruvate).

I think there are few more steps.

There is surely an energy cost to that. And if acidic conditions are not ideal, wouldn't production of lactate either contribute to or indicate low pH (proxy?). So maybe clearing lactate aids in improving pH conditions?

Yep, that is what I think too. I like that proxy idea a lot, but it's a "closed black box" kind of explaination.

I want to understand what's in that black box, and I think the OP too.

 

[padawan]

Training reduces the rate of gluconeogenesis during exercise:http://www.ncbi.nlm.nih.gov/entrez/...t_uids=7900783&query_hl=4&itool=pubmed_docsum

So, how does this help? Is it that, by a reduced rate of gluconeogenesis, we're saving ATP to fuel muscle contraction? Reading about the Cori Cycle, the process of gluconeogenesis results in a net loss of ATP.

I've also read about the "latate shuttle" where lactate helps to redistribute glycogen from muscles with higher stores to muscles with lower stores. Does "lactate" training help to improve this shuttle system?

 

[SolarEnergy]

How odd, considering Guy Thibault wrote an instruction manual for the Canadian Cycling Association in 2002 that includes blood lactate measurements at the end of each step of the load.

I have worked with Guy Thibault, he was collaborating with our team. He may have been quoted out of context on that one.

I'll give him a phone call

 

[HammerHead]

I think there are few more steps.

I figured. It's been a loooong time. And when I used study this stuff it was more bacteria than bicyclists.

 

[acoggan]

Could you comment a bit more?

Sure...but what do you want to know?

Is the whole study available?

Since you linked directly to an AJP Endo article, I assume you also have access to J. Appl. Physiol.?

What do you think of... let's say... this one http://ajpendo.physiology.org/cgi/content/abstract/274/1/E23

Is it complementing your study, or contradicting it?

I would say "complementing". That is, we studied what actually happens during exercise (at the same absolute intensity) as a result of training. The study you cite examined what happens when you infuse the hormone glucagon into trained and untrained individuals at rest. The results may differ because glucagon levels during exercise are significantly reduced as a result of training (such that even though the sensitivity/responsiveness to the hormone and/or the overall capacity for gluconeogensis is greater after training, this isn't expressed under normal situations). Alternatively (although less likely, IMO), it may be that what they observed wasn't a training effect per se, but a selection effect, i.e., individuals who are more sensitive/responsive to glucagon and/or have a greater capacity for gluconeogenesis may be more like to be successful in, and thus continue to pursue, sports.

 

[SolarEnergy]

I figured. It's been a loooong time. And when I used study this stuff it was more bacteria than bicyclists.

Sorry really. I didn't mean to be confrontative in any way.

From what I have read so far, scientists don't seem to agree on the role of lactate as a metabolic fuel, in the context of high level performance.

So I stay opened, and don't want to confront anyone on this topic.

 

[acoggan]

I think there are few more steps.

No, lactate and pyruvate are interconverted via the enzyme lactate dehydrogenase. IOW, it's a single step, requiring only lactate and NADH+ (as the proton donor).

Yep, that is what I think too. I like that proxy idea a lot, but it's a "closed black box" kind of explaination.

I want to understand what's in that black box, and I think the OP too.

I want to understand it as well (which is why I've spent >30 y studying exercise physiology).

 

[yzfrr11]

I'm pretty sure that's not quite all of it.

Lactate is indeed an energy source, but not in the muscles that you are using at that moment to produce near- or above-sustainable power.

You're kidding right? Lactate->pyruvate->Acetyl CoA->Krebs cycle. Un less you are refering to saturation of Krebs cycle, your statement is not accurate.

There is so much inaccurate info on this paticular thread that I am concerned.

 

[acoggan]

From what I have read so far, scientists don't seem to agree on the role of lactate as a metabolic fuel, in the context of high level performance.

I'm not sure what you mean by this.

 

[HammerHead]

Sorry really. I didn't mean to be confrontative in any way.

From what I have read so far, scientists don't seem to agree on the role of lactate as a metabolic fuel, in the context of high level performance.

So I stay opened, and don't want to confront anyone on this topic.

No worries at all. I think the only one here who could be rightfully irritated by confrontation is Andy. I'm still trying to figure out what his personal results (if this warren guy is informed or otherwise) has to do with his knowledge and ability to coach.

 

[Iktome]

You're kidding right? Lactate->pyruvate->Acetyl CoA->Krebs cycle. Un less you are refering to saturation of Krebs cycle, your statement is not accurate.

There is so much inaccurate info on this paticular thread that I am concerned.

No, I'm not kidding.

Think about where lactate comes from at efforts at or above the "lactate threshold", and then think about where it goes. If lactate were a completely usable energy source in the working muscle, we wouldn't have this "problem." Moreover, if the mitochondria could handle the necessary ATP production, we wouldn't have lactate in the first place (at least not at elevated levels).

Please feel free to correct any inaccurate information. As you might know, the science isn't necessarily settled on this issue.

 

[SolarEnergy]

No, lactate and pyruvate are interconverted via the enzyme lactate dehydrogenase. IOW, it's a single step, requiring only lactate and NADH+ (as the proton donor).

I think I understand that
Pyruvic acid + NADH + H+ « lactic acid + NAD+ ® lactate-Na+ + NAD+ + H+

I was just saying that there are more steps involved before lactate can be used by muscles as an energy source, not that there are more steps involved in converting lactate to pyruvate.

I want to understand it as well (which is why I've spent >30 y studying exercise physiology).

I have the biggest respect for this.

And I am glad that we finally have a "lactate unleashed" thread.

Thanks again. I may sound confrontative at some occasion, but I am just trying to validate what I read.

 

[acoggan]

I think the only one here who could be rightfully irritated by confrontation is Andy.

Irritated? Heck no...as I tell my friend Jim Martin, I like "wrestling in the mud with pigs".

 

[SolarEnergy]

If I read this correctly, the author of this paper endorses a testing methodology that Guy Thibault calls an unscrupulous way to for sports scientists to earn money, i.e. lactate threshold ramp tests == snake oil.

Just had a phone chat with Guy

What he was saying is that while he agrees that those test provide interesting info, and a indication about fitness level, we shouldn't be using the data that resulted from those test, to prescribe training.

By doing that too narrowly, we may be missing the point.

The test itself, he has nothing against it of course. But the way we use the data, generally speaking, is too narrow.

 

[acoggan]

Just had a phone chat with Guy

What he was saying is that while he agrees that those test provide interesting info, and a indication about fitness level, we shouldn't be using the data that resulted from those test, to prescribe training.

By doing that too narrowly, we may be missing the point.

Gee, now why does that sound familiar?

 

[SolarEnergy]

Gee, now why does that sound familiar?

Well I admit, everyone can do a mistake Andy.

But two PhD making the same mistake, that is rather surprising

Seriously, he also sent me some doc by email. Without even asking him, he basically sent me a chart with lactate curve over a long duration, at steady power. Gee, I must have spent 20hr trying to find one just like that. I did not mention that I was looking for this.

This guy can read my thoughts.

Thank you again Andy. Things are getting a bit more clear.

 

[WarrenG]

Well I admit, everyone can do a mistake Andy.

But two PhD making the same mistake, that is rather surprising

Seriously, he also sent me some doc by email. Without even asking him, he basically sent me a chart with lactate curve over a long duration, at steady power. Gee, I must have spent 20hr trying to find one just like that. I did not mention that I was looking for this..

SE, why do you think Guy was recording the power and HR measurements at the 2mmol/l and 4mmol/l levels?