Lactate and lactate threshold
In order to be a successful runner and progress, you need to have a training plan. Training plan helps you to understand why we are doing this or that workout. Today I will tell you about a very important concept without which we cannot continue what is lactate and lactate threshold.
Lactate is also popularly known as lactic acid, which accumulates in muscles, although in reality it is not the same thing. To understand the difference we should to remember the chemistry. An acid is a substance that is able to donate hydrogen ions (H+). Lactic acid is that a substance. When it gives a hydrogen ion the resultant product is referred to as the conjugate base of the acid and in this case is lactate. Since it is lactate that accumulates in the muscles.
I believe that it is important for all runners of any level to know and understand how works the human body.
The term Lactate Threshold has been used for many years in all sports and is one of the most commonly used metrics to create a training program around the world.
What is a lactate threshold?
I would like to give you a simple and understandable answer, but unfortunately everything is not so simple.
Do we really know what lactate is or its role in metabolism? The point is that there is still confusion about lactate and what constitutes the lactate threshold. Where did this confusion come from?
When I started to study this topic and brought up many different scientific articles, I realized that I had opened a Pandora’s box. It turns out that this particular topic is very controversial in science.
Next, I’ll tell you about what I have learned and why this knowledge is so important to us runners.
Some History
Where did the very controversial and inaccurate moments that still exist in this topic come from?
In all studies until about the 1970s, lactate was identified as a very bad end product of the glycolysis process in the body.
Let me remind you what glycolysis is. Glycolysis is the process of converting glucose into energy. The main problem in understanding glycolysis was the relationship between glycogen and lactate in muscle and other tissues.The two scientists were jointly awarded the Nobel Prize in Physiology or Medicine in 1923 for their discovery of the relationship between oxygen consumption and lactate metabolism / production / consumption in muscles.
The inaccuracy of understanding what lactate is has appeared since that moment. Since then, lactate has been considered a byproduct that occurs in working muscles due to lack of oxygen.
But a number of other earlier studies led to this inaccuracy. That is, scientists who studied this topic in the 1920s relied on earlier research from which they made conclusions, received the Nobel Prize, and this issue in science has not been raised for many years.
Let’s trace the chain of historical events a little.
The first studies on lactate date back to the 19th century; in fact, the topic of lactate, as we can see, began to be studied a very long time ago, when Nobel Prize winner Louis Pasteur suggested that lactate is formed due to a lack of oxygen during muscle contraction. This is where the chain linking lactate and oxygen began.
Then another Nobel laureate Otto Meyerhof suggested that glycogen is the precursor of lactate ( more information you can find here ). He also noticed that muscle contraction caused lactate. And already in 1923, those same scientists linked the production of lactate in the body with a lack of oxygen (anaerobic process) for which they received the Nobel Prize. Those Then they believed that lactate can be produced only in the anaerobic process (when there is a lack of oxygen). From that moment it was also considered that lactate is the end product of glycolysis, more bad than good. As we can see, we got two conclusions at once – the formation of lactate occurs when there is no oxygen in the muscles and lactate is a final, unnecessary and bad product.
What’s next?
Based on the latest research, things are not as they were thought in the 1920s. But for some reason no one raises this issue loudly in science. In fact, the process of glycolysis in the body is one of the least studied in modern science.
In newer studies, scientists are trying to justify the bad reputation of lactate. It wasn’t until the late 20th century that we began to truly understand the role of lactate in exercise and metabolism. Dr. George Brooks ( more about Dr. George Brooks works you can find here ), a metabolism specialist at the University of California, Berkeley, has studied lactate in detail for over 40 years. Much of what we know about lactate is due to its work.
What do we know about lactate today?
Lactate is always formed during glycolysis, regardless of the presence or lack of oxygen. Lactate is released even at rest. We now know that the accumulation of lactate only causes an imbalance between its production and excretion and has nothing to do with the anaerobic or aerobic process.
Now we know that lactate formation occurs under aerobic conditions, let me remind you what is aerobic and anaerobic.
Aerobically is when oxygen is used by the cells of the body to produce energy. Usually this is anything longer than a minute or two.
In Anaerobic Exercise, the cells of the body generate energy without oxygen.
As I said earlier, studies in the 1920s said that lactate is only a final and bad product.
We also know from Brooks’ scientific work that lactate is not a by-product / end-product of glycolysis. In fact, it is one of the most important glucose generators in the body. About 30 percent of all the glucose we use during exercise comes from lactate “converting” into glucose in the liver, from where the glucose goes back to the muscles. In simple words, lactate is not a final and not a bad product, but goes further into the use of the body for energy. That it is constantly present in our metabolism. With any type of load, it is also processed by the body into glucose.
Believe it or not, lactate is critical even for the brain, as it is the primary fuel that neurons use. Lactate is actually required for long-term memory and may even be involved in understanding Alzheimer’s disease.
Clearly, lactate is not just a waste product from anaerobic exercise. It is the main fuel and a key regulator of metabolism.
How does all this relate to running?
As I noted earlier, lactate accumulation occurs only when the balance between its release and excretion is disturbed. This is a key point for all runners.
We know very well that the higher the competitive and training level of an athlete, the less accumulation of lactate in the blood is observed. This is due to the increased ability to utilize lactate. Utilization of lactate can take place through the blood and it takes minutes, or through the lactate-producing muscle and it takes seconds or less.
Lactate can be exported into the bloodstream for purification and energy in virtually every organ in the body. However, this process takes, as I said earlier, takes minutes, while lactate is produced continuously during training.
Therefore, well-trained athletes export less lactate into the bloodstream, as they excrete large quantities of it directly into the lactate-producing muscle, which takes seconds or milliseconds.
Let’s now talk about how lactate is produced. As we already know, it is always produced, since it is an important part of metabolism. At some point, it begins to be produced faster than it is excreted.
During exercise, lactate is mainly produced in the fast twitch muscle fibers (which are responsible for our speed), so they use a lot of glucose for energy, which leads to the production of large amounts of lactate.
How is lactate utilized in our body and used by our body?
Brooks found that endurance training reduced blood lactate levels even when cells continued to produce the same amount ( more information about his work at this topic you can find here ). In 2000, he found that endurance athletes have increased lactate carrier molecules, which rapidly move lactate from the cytoplasm of the cell to the mitochondria. Those are utilized mainly by slowly twitching muscle fibers (responsible for our endurance) which contain methohodria, which consume lactate. It is a complex process that involves various transporters and enzymes specific to lactate. Fast twitch fibers contain a large amount of a single carrier that carries lactate from these fibers to slow twitch fibers, which in turn have a transporter that takes lactate into their fibers. This lactate is then converted in the methochondria by an enzyme (called mLDH) to finally synthesize energy.
Lactate is a source of energy for muscles. In the liver, it is reduced to glucose, which is then reused by the muscles or stored in them as glycogen. In addition, lactate can be burned directly in the muscles for energy.
Endurance training aims to improve the ability to utilize lactate by increasing the number of mitochondria that process lactate, mainly in slow muscle fibers, as well as by increasing the number of other important process elements. Both high-intensity training and endurance training increase the number of transporters to increase the transport of lactate from the fast twitch fibers.
Let’s summarize. It is important for runners to understand that it is endurance training that helps us increase the gluttony of our mitochondria, which love lactate so much.
Athletes and coaches can do a lactate test, as a lactate test is probably the best way to assess muscle performance, especially in endurance athletes. It is also probably the best method for predicting performance in endurance competitions, as well as a great parameter for identifying individual training zones for athletes. Those are not Garmin who tells you zones.
Among these training zones there is a zone known as the “lactate threshold” and this is a special training zone that we all want to train and improve. However, the only way to directly measure lactate threshold is to test for lactate.
What is lactate threshold?
The lactate threshold corresponds to the lactate in the blood, what is taken on the test and the lactate threshold is the amount of lactate in your blood that is produced at a certain rate. Let’s say this is your maximum pace at the moment at which you can run without crossing the border.
Lactate threshold is probably the most commonly used training term by coaches and athletes around the world. However, there is widespread disagreement as to what lactate threshold actually means, as well as what exercise intensity triggers it. Lactate threshold is commonly known as exercise intensity or blood lactate concentration at which we can only sustain high intensity exercise for a certain period of time. However, this is where the debate is going on: what is this for a period of time? What is this concentration of lactate in the blood? How long can we sustain a given exercise intensity?
There are many theories and hypotheses in the scientific community, and there is no consensus on what the “lactate threshold” is. The bottom line is that as muscles are subjected to more metabolic stress, there is a higher accumulation of lactate. The mitochondria in the muscles become more tense in order to clear lactate in a timely manner, and at some point, if the intensity of exercise continues, the mitochondria become saturated and therefore cannot cope with the utilization of lactate, and export it into the blood, and that’s when we see an increase blood lactate levels, so after a while we can no longer maintain a given exercise intensity
A typical training mistake that many athletes and coaches make is training at the “lactate threshold” to improve lactate clearance. This is not true as we already know!
Because we know that during exercise, lactate is mainly produced by glycolytic fibers (fast twitch), which are recruited at the “lactate threshold”. However, lactate is mostly cleared by nearby slow fibers, which have very high mitochondrial capacity and much higher levels of mLDH enzymes and MCT-1 transporters ( more scientist information you can find here ). Hence, to improve the ability to cleanse lactate, and while this is completely against common sense, it is the key to training these slow muscle fibers to stimulate mitochondrial growth and function, and to increase the MCT-1 and mLDH transporters. Lactate threshold training is also important for improving fast fiber function and mechanisms (our Turbo) and for increasing the number and function of glycolytic enzymes, as well as increasing the number of MCT-4 transporters required to transport lactate from fast twitch fibers. To then cleanse with slow-twitch fibers. Spending too much time training at the lactate threshold is also very difficult, as it requires a lot of effort and can lead to overtraining, which, judging by the reviews of professionals, often happens with amateurs.
The main question is why it is necessary to work on the lactate threshold. Let’s just say this is one of the links in the chain called progress. Knowledge and understanding of why we need this or that training simply helps us to be confident in what and why we are doing. But working on specific things is about progress.
Of course, there are many other indicators and we will talk about them in the next posts. If you have any questions or comments on this post, feel free to ask them.
All pictures of me from TDS – UTMB®, 2017.
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