Lactic acid "myth"

[Rip:30]

http://velonews.competitor.com/2014/02/training-center/on-the-bike/pointcounterpoint-lactic-acid-debunked_317172

Talk about digging yourself into a hole. First, this guy garbles the definition of pH, then he blames the low cognitive capacity of the average VN reader for his crap writing and finally, he finishes with a masterful logic-free argument about how the presence of blood lactate at low intensity must mean production rates are not tied to energy demand.

Concentrations matter guy. Lactic acid production rates change. O2, pyruvate and NAD+ concentrations change. Energy demands and ATP availability change. Just because baseline levels of blood lactate are not zero does not mean lactic acid production stays the same at high and sustained intensity or has nothing to do with fatigue.

 

[CoachFergie]

That concept is reflected in several physiology and biochemistry texts.

Dr Ben Miller did research on it a while ago.

http://cyclingnz.com/cnz5_science.php?a=74

 

[Rip:30]

No that's a different argument, Richards et al. 1998 are demonstrating that lactate efflux increases with exercise intensity, and without an intracellular depletion of PO2. That's just suggesting that some other component of O2 reduction pathway is rate limiting rather than supply of O2. They go on to suggest a role for catecholamines in regulating pyruvate reduction to lactic acid. Look at fig 2. muscle pH is lower when lactate efflux levels are higher.

 

[Master50]

Maybe you could translate this into layman for the rest of us? While the article might have inaccuracies and poor sentence structure I stood a chance of understanding the subject. So far this thread is worthless as a critique because you are speaking to biochemists and not cyclist. I am interested in you opinion if I could understand it.

 

[FrankDay]

http://velonews.competitor.com/2014/02/training-center/on-the-bike/pointcounterpoint-lactic-acid-debunked_317172

Talk about digging yourself into a hole. First, this guy garbles the definition of pH, then he blames the low cognitive capacity of the average VN reader for his crap writing and finally, he finishes with a masterful logic-free argument about how the presence of blood lactate at low intensity must mean production rates are not tied to energy demand.

Concentrations matter guy. Lactic acid production rates change. O2, pyruvate and NAD+ concentrations change. Energy demands and ATP availability change. Just because baseline levels of blood lactate are not zero does not mean lactic acid production stays the same at high and sustained intensity or has nothing to do with fatigue.

I agree with you. This guys understanding of the system and concepts suck. Some other examples. From the original article.

If you had lactic acid in your blood, you’d have to have a pH under six…

And, the letter to the editor response wasn't much better

That isn’t true. At low concentrations, the pH would remain in the sixes.

Both of these writers seem to have no awareness of nor understanding of the purpose of the buffering system in the body. The purpose being to maintain pH within a narrow band whether strong or weak acid is added to the mix.

Then there is this

A hydrogen ion does leave the cell with lactate, but it is believed that there again, the lactate is helping to maintain intracellular pH by acting as a co-transporter. Reberg et al. concluded that the hydrogen ion was not produced by lactic acidosis but by ATP hydrolysis. They go on to say, “there is no biochemical support for lactate production causing acidosis. Lactate production retards, not causes, acidosis.”

All of these people seem to be missing the basic point that "lactate" is produced because lactic acid is being discharged into a buffered solution which is trying to keep the pH near 7.4 and at a pH of 7.4 lactate will predominate. If the same lactic acid were being discharged into the body with the same physical properties as a water solution the pH would almost immediately drop below physiological compatibility and the organism would not only stop exercising but, probably, die.

Then, this:

What all this means is that lactate never contributes to acidity but in fact acts as a buffer

Lactate is not a buffer. Lactate is the result of lactic acid being placed into a buffered solution. I challenge anyone to go to a human physiology textbook and find lactate being included as a body pH buffer mechanism.
Then this:

Lactate is constantly being produced in the body and actually acts as an important fuel. Its rise in the blood has as much to do with our ability to clear it as its formation. I have in fact worked with athletes who have very high lactate levels while working at low aerobic levels due to poor clearance mechanisms.

This is part of the "lactate is good for you" argument by people who really don't understand physiology. Because the body has a mechanism for clearing lactate, once produced doesn't mean that the body relishes it, to be used as a fuel, when exercising.
And, the last straw:

Ultimately the key point I was trying to get across was that at no time does lactate physiologically function as an acid or contribute to metabolic acidosis.

As if lactic acid and lactate were not tied together somehow. A greater misunderstanding of body chemistry would be hard to find. But, a high percentage of cyclists will take this BS as gospel.

 

[FrankDay]

Maybe you could translate this into layman for the rest of us? While the article might have inaccuracies and poor sentence structure I stood a chance of understanding the subject. So far this thread is worthless as a critique because you are speaking to biochemists and not cyclist. I am interested in you opinion if I could understand it.

While you may have stood a chance to understand what he was saying it is a good thing you didn't because it is so wrong.

 

[rhubroma]

All I know is that if you have the equivalent of three eye-drops of lactic acid in your blood stream, then you are essentially fried and need to recover. How an organism builds that from athlete to athlete, or how it gets metabolized with more or less efficiency among individuals is a mystery.

 

[FrankDay]

That concept is reflected in several physiology and biochemistry texts.

Dr Ben Miller did research on it a while ago.

http://cyclingnz.com/cnz5_science.php?a=74

Another overly simplistic view that is simply wrong.

The anaerobic threshold theory is based on the idea that an oxygen deficit results in lactate production and accumulation and that breathing increases in an effort to buffer increasing acidity. The theory falls apart in a number of places. First and foremost, there is very little evidence that exercising muscle is ever deficient in oxygen. In reality, most measurements indicate that skeletal muscle maintains a critical level of oxygen. This makes intuitive sense because without oxygen most tissues will not survive.

Ugh, perhaps he missed the purpose of the anaerobic metabolism pathway i.e., to provide the cells with a source of energy to keep them alive (at least for a short while) in the absense of oxygen. And, there is plenty of evidence that exercising muscle is ever deficient in oxygen. Otherwise, how does one explain the increase in lactic acid production as one exercises harder and harder. The problem is the entire muscle is not deficient, only those muscle cells that have the furthest diffusion distance from the capillary bed.

We are familiar with what happens when heart muscle goes without oxygen, a heart attack, so you would have to ask why skeletal muscle would allow the same to happen.

Heart attacks occur because of a blockage of blood flow to a portion of the heart, not because the heart exercises too hard. Skeletal muscle dies when blood flow is blocked to them also. The difference is the skeletal muscle always goes anaerobic before the heart muscle does when exercsing, at least in normal physiology.

A particularly insightful study made measurements of oxygen concentration in skeletal muscle during increasing intensities of exercise (Figure 1).

Arterial oxygen concentration (which is what I assume they are measuring here) is not the same as mitochondrial oxygen concentration, which is what determines what pathway is used to generate energy.

The reality of the situation is that lactate production in the muscle occurs under full aerobic (with oxygen) conditions. Lactate production does not equate with a lack of oxygen.

Phooey. How on earth do they account for the production of lactate under "fully aerobid" conditions then? It is simple to account for in that there are probably a few cells at the extremes of the diffusing distance from the capillary that are anerobic. This production of lactate could be part of the homeostatic mechanism causing local regulation of blood flow. It does not mean that no cell is ever anaerobic under aerobic conditions.

To me the term "anaerobic threshold" simply means the point where the production of lactic acid increases to the point that metabolism of lactate is overwhelmed and pH will start to drop. The higher one is above that point the faster the pH will drop and the sooner one is forced to stop exercising. Such simplistic explanations simply come from people who really don't understand the physiological big picture.

 

[Master50]

Then, this:Lactate is not a buffer. Lactate is the result of lactic acid being placed into a buffered solution. I challenge anyone to go to a human physiology textbook and find lactate being included as a body pH buffer mechanism.


Frank
My limited understanding of this subject as presented would challenge all the text books so if this is a new idea then of course it disagrees with the text books and if this new idea was shown to be the true mechanism then everyone still clinging to the old paradigm is the one without a clue. Such is the nature of any revolution. Not saying who is right here since I really don't have the education to argue for or against.
Now this is the third article I have read about this "NEW" idea of Lactic acid.
I am not really concerned about who is right. I am more concerned about the pain I feel from hard efforts. What I do know is training improves the ability to tough it out. I'll be watching for your paper just since you sound like you know what you are talking about. My problem with the strength of your opinion is you are arguing from the textbook perspective and these articles are definitely not explaining it as you have. It claims to be a revolutionary understanding so it would be logical that the current textbook knowledge needs an edit and you need to learn something opposite to what you currently believe. You know that no one can go faster than the speed of sound and survive! The earth was created in 7 calendar days some 6600 years ago. I hope you see my point! Your rebuttal is textbook

 

[FrankDay]

Then, this:Lactate is not a buffer. Lactate is the result of lactic acid being placed into a buffered solution. I challenge anyone to go to a human physiology textbook and find lactate being included as a body pH buffer mechanism.


Frank
My limited understanding of this subject as presented would challenge all the text books so if this is a new idea then of course it disagrees with the text books and if this new idea was shown to be the true mechanism then everyone still clinging to the old paradigm is the one without a clue. Such is the nature of any revolution. Not saying who is right here since I really don't have the education to argue for or against.
Now this is the third article I have read about this "NEW" idea of Lactic acid.
I am not really concerned about who is right. I am more concerned about the pain I feel from hard efforts. What I do know is training improves the ability to tough it out. I'll be watching for your paper just since you sound like you know what you are talking about. My problem with the strength of your opinion is you are arguing from the textbook perspective and these articles are definitely not explaining it as you have. It claims to be a revolutionary understanding so it would be logical that the current textbook knowledge needs an edit and you need to learn something opposite to what you currently believe. You know that no one can go faster than the speed of sound and survive! The earth was created in 7 calendar days some 6600 years ago. I hope you see my point! Your rebuttal is textbook

The problem the "new idea" of lactic acid has is in trying to explain where the lactic acid (or lactate) is coming from during those "aerobic" conditions. What is the pathway by which it is made and then where is this pathway occurring. Since the lactate is there during "aerobic" conditions it needs to be being made somewhere. Where? If you can answer and understand this question then one will start to have a grasp of the underlying physiology. The textbook explanation explains all. The new explanation falls flat on its face (edit: and is being put forth by people who don't understand the current textbook explanation of acid/base and metabolic physiology so they are pulling ideas out of thin air to explain a tiny bit of the picture in simplistic terms they can understand). It is such hogwash coming from people with little understanding of the physiological big picture.

 

[FrankDay]

My limited understanding of this subject as presented would challenge all the text books so if this is a new idea then of course it disagrees with the text books and if this new idea was shown to be the true mechanism then everyone still clinging to the old paradigm is the one without a clue. Such is the nature of any revolution. Not saying who is right here since I really don't have the education to argue for or against. )

Here is another take. It seems that this new theory derives solely from the fact that lactate is present during aerobic conditions. Therefore, it is logical to presume that lactate is unimportant and has nothing to do with what is going on during "anaerobic conditions". These people need to be asking the question as to where on earth is the lactate coming from during aerobic conditions rather than trying to say that because of this I don't need to understand lactate physiology as it applies to exercise so I am going to rationalize why I am ignoring this "problem". Their new theory simply explains nothing and has holes so big you could lose a truck or car in them.

 

[Race Radio]

http://velonews.competitor.com/2014/02/training-center/on-the-bike/pointcounterpoint-lactic-acid-debunked_317172

Talk about digging yourself into a hole. First, this guy garbles the definition of pH, then he blames the low cognitive capacity of the average VN reader for his crap writing and finally, he finishes with a masterful logic-free argument about how the presence of blood lactate at low intensity must mean production rates are not tied to energy demand.

Concentrations matter guy. Lactic acid production rates change. O2, pyruvate and NAD+ concentrations change. Energy demands and ATP availability change. Just because baseline levels of blood lactate are not zero does not mean lactic acid production stays the same at high and sustained intensity or has nothing to do with fatigue.

Thanks....I thought I was just too stupid to understand what he was writing.

 

[Ripper]

Thanks....I thought I was just too stupid to understand what he was writing.

Nope, it was just that bad ...

 

[King Boonen]

What is this s**t? Do they just publish anything these days without even bothering to check it?

 

[DirtyWorks]

What is this s**t? Do they just publish anything these days without even bothering to check it?

Velonews? Yes. The same guy was credited with a story that repackaged excuses for permitting doping. Typical for them. It's the equivalent of North Korean media. The UCI does no wrong.

I'm guessing they are going to try to package it as a coaching program. People believe Carmichael was a good coach, so why not this joker?

 

[King Boonen]

Velonews? Yes. The same guy was credited with a story that repackaged excuses for permitting doping. Typical for them. It's the equivalent of North Korean media. The UCI does no wrong.

I'm guessing they are going to try to package it as a coaching program. People believe Carmichael was a good coach, so why not this joker?

I could have given this to first year students and they would've asked what he was smoking.

Gluconeogenesis is like drinking a sports drink?!!?! WTF!?!?!?!

 

[King Boonen]

Sorry, I'm ranting now but this is basic biochemistry! It's utter rubbish. You could look up gylcolysis, the Krebs cycle, the Cori cycle and gluconeogenesis on Wikipedia and conclude that what he is saying is completely wrong. Does he thik lactate is magically transported to the liver?! If he thinks fermentation is so favourable then maybe he'd like to stop breathing oxygen and see how that works out for him?! Does he actually know what ATP is and how it is used?! Has he even bothered to walk down to the Biochemistry department, of which CSU seem to have a fairly large one, and ask them if any of this makes sense?!


I'm not even a biochemist and it's making me angry, I feel sorry for the guys reading this who are.