Lactic acid is your friend, no matter what your fitness trainer says

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

Lactic acid does not "acidify" muscles, but increases endurance and protects the brain.

What is lactic acid and lactate

Our body constantly needs energy for organs and muscle contraction. Carbohydrates enter the body with food. In the intestine, they are broken down into glucose, which then enters the bloodstream and is transported to cells in the body, including muscle cells.

In the cytoplasm of cells, glycolysis occurs - the oxidation of glucose to pyruvate (pyruvic acid) with the formation of ATP (adenosine triphosphate, the main fuel of the body). Then, due to the enzyme lactate dehydrogenase, pyruvate is reduced to lactic acid, which immediately loses a hydrogen ion, can add sodium (Na +) or potassium (K +) ions and turns into a lactic acid salt - lactate.

As you can see, lactic acid and lactate are not the same thing. It accumulates in the muscles, it is lactate that is excreted and processed. Therefore, it is incorrect to talk about lactic acid in muscles.

Until 1970, lactate was considered a byproduct that occurs in working muscles due to lack of oxygen. However, research in recent decades has refuted this claim. For example, Matthew J. Rogatzki in 2015 found Lactate is always the end product of glycolysis, that glycolysis always ends with the formation of lactate.

This is also claimed by George A. Brooks of the University of California, who has studied lactic acid for over 30 years. The accumulation of lactate only shows a balance between its production and elimination and is not related to aerobic or anaerobic metabolism.

Lactate is always formed during glycolysis, regardless of the presence or lack of oxygen. It is produced even at rest.

Why many people dislike lactic acid

Myth 1. Lactic acid causes muscle pain

This myth has long been disproved, but some fitness trainers still blame lactate for muscle soreness, or delayed muscle pain. In fact, lactate levels drop dramatically within minutes after you stop exercising and bounce back completely about an hour after exercise.

Thus, there is no way lactate can cause muscle pain 24–72 hours after exercise. You can read about what mechanisms make your muscles ache after training in this article.

Myth 2. Lactic acid "acidifies" muscles and causes them to fatigue

There is a widespread belief that blood lactate levels affect muscle function. However, in fact, lactate is not to blame for this, but hydrogen ions, which increase the acidity of tissues. When the pH balance shifts to the acidic side, acidosis ensues. There are many studies showing that acidosis negatively affects muscle contraction.

The scientific article Biochemistry of exercise-induced metabolic acidosis by Robert A. Robergs states that hydrogen ions are released each time ATP is broken down to ADP (adenosine diphosphate) and inorganic phosphate with energy release …

When you work at medium intensity, hydrogen ions are used by mitochondria for oxidative phosphorylation (the reduction of ATP from ADP). When exercise intensity and the body's need for energy increase, ATP recovery occurs primarily through the glycolytic and phosphagenic systems. This causes an increased release of protons and, as a consequence, acidosis.

Under these conditions, lactate production is increased to protect the body from pyruvate accumulation and the supply of NAD + required for the second phase of glycolysis. Robergs suggested that lactate helps to cope with acidosis because it can carry hydrogen ions out of the cell. Thus, without the increased production of lactate, acidosis and muscle fatigue would have occurred much faster.

Lactate is not to blame for muscle fatigue during intense exercise. Fatigue causes acidosis - an accumulation of hydrogen ions and a shift in the pH of the body towards the acidic side. Lactate, on the other hand, can help combat acidosis.

How lactate is good for health and fitness

Lactate is an energy source

In the 80s and 90s, George Brooks proved Lactic Acid Not Athlete’s Poison, But An Energy Source - If You Know How To Use It, that lactate passes from muscle cells into the blood and is transported to the liver, where it is restored to glucose in the measles cycle. The glucose is then transported again through the blood to the working muscles and can be used for energy production and stored as glycogen.

What's more, even muscles can use lactate as fuel. In 1999, Brooks discovered that endurance training reduced blood lactate levels even when cells continued to produce the same amount. In 2000, he found that endurance athletes have an increased number of lactate carrier molecules, which rapidly move lactate from the cytoplasm of the cell to the mitochondria.

In further experiments, scientists found not only carrier proteins inside the mitochondria, but also the lactate enzyme dehydrogenase, which triggers the conversion of lactate into energy.

Scientists have concluded that lactate is transported to the mitochondria and burned there with the participation of oxygen for energy production.

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.

Lactate increases endurance

Lactate helps to increase oxygen consumption, which also has a positive effect on endurance. A 2006 study found that lactate, unlike glucose, increases the amount of oxygen taken up by mitochondria, which allows them to generate more energy.

And in 2014, it was found that lactate reduces the response to stress and increases the production of genes involved in creating new mitochondria.

Lactate increases the amount of oxygen you consume so your body can handle stress longer.

Lactate protects the brain

Lactate prevents excitotoxicity caused by L-glutamate. This is a pathological condition in which, due to the excessive activity of neurons, their mitochondria and membranes are damaged and the cell dies. Excitotoxicity can cause multiple sclerosis, stroke, Alzheimer's disease, and other diseases associated with damage to nerve tissue.

A 2013 study found that lactate regulates neuronal activity, protecting the brain from excitotoxicity.

In addition, lactate provides the brain with an alternative food source when glucose is in short supply. In the same 2013, scientists found that a slight increase in lactate circulation allows the brain to function normally under hypoglycemic conditions.

What's more, a 2011 study found that glucose is not enough to provide energy during intense synapse activity, and lactate can be an effective energy source that supports and enhances brain metabolism.

Finally, a 2014 study found that lactate increases the amount of norepinephrine, a neurotransmitter that is needed to supply the brain with blood and focus.

Lactate protects the brain from excitotoxicity, serves as a source of energy and improves concentration.

Lactate promotes muscle growth

Lactate creates good conditions for muscle growth. A 2015 study found that caffeine and lactate supplementation increased muscle growth even during low-intensity workouts by activating stem cells and anabolic signals: increasing the expression of myogenin and follistatin.

As early as 20 years ago, scientists discovered that after the introduction of lactate and exercise (swimming) in male mice, the amount of testosterone in the blood plasma increases. In addition, the amount of luteinizing hormone increases, which also promotes the secretion of testosterone. And this, in turn, has a positive effect on muscle growth.

Lactate increases the secretion of hormones needed for muscle growth.

How to increase the amount of lactate

1. Eat something high in carbohydrates an hour before your workout: sugary fruits, chocolate, cereals. Remember, lactate is produced when glucose breaks down.
2. Try to give your best. For example, try a sprint or high-intensity interval training (HIIT). Do this workout twice a week in addition to your regular activity, and gradually your body will become accustomed to produce more lactate for increased endurance, muscle growth and brain protection.