In the world of sports, many technical terms or names of substances are used that we do not know what they are. You may have heard of lactic acid, also known as lactate. This chemical substance has a determining function in anaerobic metabolism.
Popularly it has always been related to the pain caused by shoelaces, but science has refuted that belief. Even so, it is interesting that you understand how it affects sports performance.
How is it produced?
The body feeds the muscles through a process called glycolysis, where you break down glucose (from the food you eat) and produce adenosine triphosphate (ATP). ATP is what your muscle cells use for fuel. But the amount of ATP generated from glycolysis depends on whether oxygen is present during glycolysis.
When we exercise at high intensities, the body increasingly relies on fast-twitch muscle fibers for energy. But these particular fibers don't have the ability to use oxygen as efficiently. So in heavy training, such as when lifting heavy weights or pushing cardiovascular limits, ATP demand is high, but oxygen levels are low. When that happens, glycolysis becomes anaerobic. In anaerobic glycolysis, the end product of glucose breakdown is lactate. This results in higher levels of circulating lactate in the bloodstream.
Furthermore, researchers have discovered that lactate is produced more frequently than we thought, even under aerobic conditions.
Lactic acid is the result of use of glucose as fuel when there is no oxygen present. The common thing is that it appears in high intensity exercises and medium duration. This acid is responsible for marking two different energy paths (alactic anaerobic and lactic anaerobic) when our body does not have the necessary oxygen to obtain energy.
In other words: when we perform high intensity, short duration (HIIT) exercise, the body uses glucose for energy and breaks it down into lactic acid. If this substance is not removed or used, we will notice some muscle fatigue (which some confuse with stiffness).
Why does muscle fatigue appear?
Actually, it is not necessary to perform intense training for the body to generate lactic acid; but having such a low concentration, we will not notice any symptoms. Instead, when we produce too much, the body may not be able to eliminate or use it, and that is why muscle fatigue appears with intense training. However, although a high level of this acid is related to tired muscles, lactate does not cause fatigue. What really achieves it is the increase in acidity in the tissue.
If there is a large amount of lactic acid, it is possible that our body inhibits some anaerobic enzymes and the muscles run out of energy. In addition, this excess also affects the absorption of calcium in the muscles and the fibers will be less capable of contracting.
The most common symptoms are a burning sensation in the muscles, cramps, nausea, weakness, or a feeling of tiredness. It's just your body's way of telling you to stop. These signs appear instantly, so the pain you experience a day or two later has nothing to do with lactic acid. It's just the muscles recovering from the workout you did. This pain is known asdelayed onset muscle soreness«.
In summary, generating an excess of lactic acid is a problem for muscle contraction, since neither energy reaches it nor favors the contraction of the fibers.
How much lactic acid is too much?
A buildup of lactic acid is key to performance, although each person has a different threshold. That is, the point at which acid accumulates significantly above resting levels when we are exercising. The higher the intensity of the exercise, the more we will tend to accumulate.
There are some training sessions that can favor an improvement in threshold. That is, to help delay the point at which that acid accumulates and fatigue appears. With this we could improve speed marks, for example, since our body would support a high intensity without getting fatigued.
Is it true that we can "train" to tolerate it?
To improve the threshold, you have to train under the effects of lactic acid, so that your metabolism adapts on its own. You will learn how to reuse or remove it effectively in order to progress.
Even so, there is no set amount of threshold. Even if two people are consuming the same level of oxygen, performance can be very different as a result of that acid. This means that if an athlete has the threshold at 75% of his VO2 max, he will have a higher performance compared to another who has 60% (this figure is common in people who do not train).
So, from now on, try to improve by dealing with muscle fatigue. That does not mean that you take your body to the extreme, since you could end up injuring yourself or endangering your health.
What is the lactate threshold?
The lactate threshold is the point at which the body cannot eliminate lactate at the rate at which it is produced. This is when lactate begins to build up in the blood. It can occur as a result of increased production or decreased lactate clearance. During exercise, lactate levels increase and it is recycled to fuel other cells and processes in the body.
Oxygen is required to metabolize lactate. But when exercise reaches an intensity beyond what the aerobic system can handle, lactate builds up in the blood. Once the lactate threshold is reached, the body produces lactate and releases excess hydrogen ions, resulting in a drop in pH and a more acidic environment in muscle cells, causing that burn.
For example, doing interval squats with a medium weight for 10 to 15 repetitions will likely result in a pH-related burn in your lower body. This burn is the direct result of the body metabolizing glucose faster than it can supply oxygen.
At this time, we breathe harder and may feel short of breath as the body tries to increase its oxygen intake. We may stop exerting ourselves and notice the burn dissipate as the cellular pH rises and the acute fatigue in the muscles begins to fade.
How to prevent?
Although there is no secret to getting rid of lactate, it is possible increase lactate threshold.
No matter how fit we are, if we exceed the lactate threshold, the clock immediately starts ticking to determine how long you can sustain that effort. On the contrary, exercising below the lactate threshold allows us to maintain energy for a long time.
You can train the body to work at a higher intensity without lactate buildup and increase your lactate threshold. However, this requires the efficiency of the aerobic system to improve. While this isn't technically "preventing" lactate buildup, it does mean we can run faster and longer before reaching the point of muscle burn.
In fact, the goal of aerobic training for competitive and performance purposes revolves around increasing the lactate threshold.
For example, a competitive runner who maintains a pace of 10 kilometers per hour for several kilometers will use primarily the aerobic system. A less conditioned person can run the same pace, but because their aerobic system is not as efficient and trained, they will rely on anaerobic energy to keep up, resulting in increased lactate and fatigue due to metabolite buildup. .
If this second person continually trains at or near their current lactate threshold, they will be able to run at that pace without using anaerobic energy, and this will eliminate the associated lactate buildup. Regardless, once you reach your lactate threshold, you are subject to all the effects associated with lactate buildup and there is little you can do other than rest and breathe deeply.