I don't understand Lactate Threshold

"Anaerobic Threshold (AT) was a term applied to the lactate inflection point, or the point at which the appearance of lactate in the blood accumulates faster that its rate of use. ...But ...no "anaerobic" threshold exists.

"LT is a more descriptive name for the lactate inflection point than AT."

I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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I like metabolism wrote:
I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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I like metabolism wrote:
I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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These "threshold" terms will never make any sense because they're based on a simplistic view of gas transport in the blood.

For example, the end result of the reactions that lower acidity is carbon dioxide that must be exhaled. But how fast it can be "cleared" is not constant because carbon dioxide regulates vasodilation and thus speeds the mechanism to eliminate itself when it builds up.

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malmo wrote:

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I like metabolism wrote:
I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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Well done.

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I don't understand lactate threshold on any scientific level, but I know how to approximate it from a race time and to some extent just by effort. I've found that training around that intensity to be beneficial, whether it's a sustained effort or long intervals.

To really over simplify it, it's like your stamina bar in a video game. Better lactate threshold means more stamina (bigger stamina bar).

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otter wrote:

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I like metabolism wrote:
I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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True, but to add to this:

- lactate is defined because it is large enough to be measured in a test and is linear to the amount of H+ produced and cleared.

- A slight correction is that lactate levels are individualized in terms of when they reach that tipping point and have a lot to do with fiber type and to some degree fitness. Someone else’s LT might be 8 mmmol while mine might be 6.5 for example. I have seen 4 as a typical LT threshold level example which it could be but also might not be again based on the individual.

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The interesting is the practical use, keeping the lactate level in the zone during threshold training. Good way to control the intensity. Proven to be effective training that can be of a relatively high volume with relatively limited recovery

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I like metabolism wrote:

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otter wrote:

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I like metabolism wrote:
I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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True, but to add to this:

- lactate is defined because it is large enough to be measured in a test and is linear to the amount of H+ produced and cleared.

- A slight correction is that lactate levels are individualized in terms of when they reach that tipping point and have a lot to do with fiber type and to some degree fitness. Someone else’s LT might be 8 mmmol while mine might be 6.5 for example. I have seen 4 as a typical LT threshold level example which it could be but also might not be again based on the individual.

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Oh, I wasn't indicating that 8mmol was related to lactate threshold... It is simply a standardized value that is used as a "validation criteria" for VO2 max testing... so it should be above the lactate threshold for most people. It was just making the point that the idea that when we "go anaerobic" it means we're not using aerobic metabolism. Quite the opposite, when endurance athletes are at very high intensities, we're maximizing both energy systems.

Very true though about the clinical relevance of lactate. The blood concentration of lactate is indicative of hydrogen production and is therefore meaningful still, even if the lactate itself is not problematic

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Bad Wigins wrote:
These "threshold" terms will never make any sense because they're based on a simplistic view of gas transport in the blood.

For example, the end result of the reactions that lower acidity is carbon dioxide that must be exhaled. But how fast it can be "cleared" is not constant because carbon dioxide regulates vasodilation and thus speeds the mechanism to eliminate itself when it builds up.

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Also, I should add that higher lactate levels levels can be achieved with fast twitch runners although they clear them at a slower rate. Yet another curve ball to throw in there.

The terminology is a mess. We've also got LT, LT1 and LT2, VT1 and VT2, Aet, AnT. I think the OBLA terminology is good and fairly precise.

The problem with OBLA as a training target is (1) it's a moving target, even on a DAILY basis and (2) it's difficult to identify precisely using a standard step test. If we want to be really accurate, we should be using the step test as a first stage. Then, a few days later, we'd do some continuous runs at a few paces right around our selected LT pace, checking lactate levels periodically. If your 10 minute reading is higher than your 7 minute reading, you're over LT.

You also have to be careful to adjust your treadmill paces to outdoor paces, but that's a pretty solvable issue.

Yeah, I understand more why you need to train at certain paces with certain rests from doing it, more than the science. I like this article that seems to cover all the bases.

https://runnersconnect.net/training-with-thresholds-in-the-right-zone/

There seems to be a consensus that there is a pace at which you can't comfortably talk, can probably go a few kilometres further in a race-like situation, but are not particularly enjoying things, and which won't burn you out tomorrow, and that this is a productive pace at which to train frequently.

Unless you have the scientists around you and the willingness to have your finger pricked after every interval, more than that is over-thinking it.

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I like metabolism wrote:
I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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Curbside Pickup wrote:

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malmo wrote:

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I like metabolism wrote:
I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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Well done.

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Here is what I have in my "notes"

Anaerobic Threshold / Lactate Threshold

Anaerobic Threshold: The line separating mild lactate production and a spike in lactate production. The graph switches from mild positive slope to extreme positive slope.

Lactate Threshold: The pace that causes 4mmol/L of blood lactate as tested in a lab.

From my understanding, both terms are trying to get at the same idea. The difference is that LT is specifically defined a 4mmol/L, while Anaerobic Threshold is more of a theoretical idea and the actual measurement could be different for each person.

Happy to be corrected if I am off-base.

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I like metabolism more wrote:

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Curbside Pickup wrote:

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malmo wrote:

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I like metabolism wrote:
I've typically seen anaerobic threshold and lactate threshold as synonymous terms in scientific literature. Some textbooks prefer the term OBLA (onset of blood lactate accumulation) as it is the most accurate descriptor. I've seen the anerobic threshold somewhat inaccurately described as the point at which our bodies shift from aerobic to anaerobic metabolism, but that's not quite right, as we don't just flip a switch, with aerobic turning off and anaerobic turning on. It's more like a dimmer switch... And we don't really every turn off either system. At rest, we have a measurable blood lactate level. And at VO2 max, we are optimizing both systems (a lactate level above 8 mmol and a high RER are both indicative of anaerobic contributions to energy production, and these are criteria used to determine if it is a true VO2 max effort).
Regarding lactate vs lactic acid, they are often used interchangably because we produce lactic acid, but it immediately dissociates into lactate and a hydrogen ion. The lactate isn't the issue, as it is simply a substrate that can be converted back to pyruvate for fuel at rest or low intensity... it is the hydrogen ion that results in pain and fatigue

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Well done.

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Here is what I have in my "notes"

Anaerobic Threshold / Lactate Threshold

Anaerobic Threshold: The line separating mild lactate production and a spike in lactate production. The graph switches from mild positive slope to extreme positive slope.

Lactate Threshold: The pace that causes 4mmol/L of blood lactate as tested in a lab.

From my understanding, both terms are trying to get at the same idea. The difference is that LT is specifically defined a 4mmol/L, while Anaerobic Threshold is more of a theoretical idea and the actual measurement could be different for each person.

Happy to be corrected if I am off-base.

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There is no spike in lactate when you cross this so called threshold. If there was then there would be a big metabolic difference between half marathon pace and 10k pace, when of course it is only a small difference.

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