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Lactic acid: myths and facts

Lactic acid: myths and facts

Aches, muscle burns, cramps ...

It is common to hear that this phenomenon results from the production of lactic acid, a poison that limits exercise performance.


Unfortunately this is an error conveyed in the sports world for many years ...

1) The reality of lactic acid

Lactic acid cannot exist in our body and in our muscles.

This is because the body works in a narrow pH range, and lactic acid has a pH that is far too acidic to be present in the blood.

It's a terminology problem, and lactic acid is mistaken for lactates.

2) lactates

Previously we thought that a high production of lactates was bad for performance.

The latest studies have shown us the opposite, and its production is a real source of energy for our muscles, thanks to various physiological mechanisms of recycling and transformation.


The body will produce energy through glycolysis by a process of degradation of glycogen (stock of sugars in the body).

This glycolysis is closely linked to the production of lactates which is the end result.

The more intense the effort, the greater the stress there is on the glycolysis process in order to produce energy to activate muscle contraction, and the higher the concentration of lactates measured in the blood.

The destination of lactates:

A large part is transformed and used in energy available for the organism

The other part to replenish glycogen reserves (stock of sugars) in the liver

3) Train to make better use of lactates

We produce lactates at all levels of effort and not only in the so-called anaerobic process (without oxygen).

But the more intense the effort, the higher the production of lactates.

Thanks to training, the body will put in place physiological adaptations to make better use of the lactate mechanism, to produce more while optimizing its recycling at high intensities.

The best athletes are those with the highest blood lactate levels, unlike untrained athletes.

An untrained athlete will be limited in his effort not by a high production of lactates, but on the contrary because he does not produce enough, and that he does not benefit optimally from the process of recreating energy.

This leads us to review certain methodologies at the training level, in particular for the preparation of long endurance efforts (ultra trail, ultra cycling, iron man…).

In practice :

  • Performing high and very high intensity sessions
  • Physical efforts with strong muscular demands

Polarization is therefore essential for progression, with an alternation of intensive sessions necessary for the establishment of physiological adaptations to the lactate mechanism, and efforts at low intensity in endurance.

4) Pain and fatigue on exertion: who is responsible?

With the theory of the central governor of Timothy Noakes, that gives us elements of answer.

Depending on multiple parameters (energy stock, hydration, body temperature, etc.), the brain will send signals to the body to slow down a so-called too intense or unusual effort, and thus guard against possible risks for the body, by setting up a safety margin.

Brain function is central to the regulation of physical effort, with the aim of always maintaining the vital balance by anticipation.

 "The feeling of fatigue is therefore partly the result of an emotion, rather than a purely physical limit"

With this vision, training would allow us not only to develop our physiological capacities, but to push our limits from a mental point of view to exceed the thresholds of fatigue and pain.


Muscle fatigue during exercise results from many factors, and lactic acid is not the enemy responsible since it does not exist in the body.

We must talk about the production of lactates which are not waste, but essential elements for the creation of energy, to be transformed and used by the body, during and after exercise.

Through training, we can optimize the production and recycling of lactates in order to improve athletic performance.


This content has been published by our Ambassador Guillaume Klein (Personal Coach Sports nutrition and health expert / Ultra endurance specialist)
  • Nutriformation graduate specializing in micronutrition and nutritherapy
  • Trained in sports nutrition by the Evonutri Positive Nutrition Academy
  • Ultra Trail coach trained by the Auvergne Rhône-Alpes Athletics League
  • Dietitian nutritionist FC Metz professional group (since 2018)
  • Dietitian nutritionist FC Metz training center (since 2019)

Passionate about sport, and ultra endurance athlete in running and ultra cycling, Guillaume was able to test on himself the benefits of a natural nutritional balance, appropriate to his real needs, and of a specific adapted training. Guillaume appreciates quality products which respect the nutritional needs of the athlete, but also from a health point of view, a composition as natural as possible.

You too can take advantage of his advice and find all our products on this site

If you would like more information or advice, do not hesitate to contact Guillaume via his site uses cookies to provide the best user experience. Please accept cookies to continue exploring our site
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