Have you ever wondered why the muscles burn during an intense workout? This uncomfortable feeling, often the reason you want to give up, happens when something called lactate is flowing through the muscles. Here, we will explain what is called lactic acid ‘lactate’ and how energy is generated under different physical efforts.


When you do Freeletics workouts or a lot of challenging repetitions like 100 Burpees, 50 Back Squat with weight or a sprint, you have to give the maximum as fast as possible. One of the many factors that contribute to a great time in a workout is the ability to overcome the lactate produced. Lactate? Have you never heard of it? Lactate appears when your body breaks carbohydrates (glucose) under extreme physical exertion. Every Free Athlete has already experienced what it means to have lactate “flowing” through the body. Before we begin to explain what lactate is, we need to clarify some terms and processes that are very important to understand how lactate is produced in the body. First we will talk about adenosine triphosphate, the unit of human energy.


Depending on the intensity and duration of a workout, the energy demand of the human body, or more precisely of the cells of the muscles, varies. The body burns carbohydrates, fats and proteins through different processes to provide energy to the cells. The energy produced allows the muscles to contract. Then energy is supplied to the body in the form of adenosine triphosphate (abbreviation: ATP), also known as the “energy currency” of the body.

Muscles can store only a small amount of ATP. For that reason the ATP has to be synthesized again and again. The way to (re) synthesize the ATP energy currency depends on the type of physical effort and how much oxygen can be channeled into the cells. It is a very complex cycle with many metabolic byproducts that are necessary to synthesize ATP. One of those metabolic byproducts is called lactate. It occurs in the so-called anaerobic energy generation. You are probably wondering what anaerobic energy production is and what it has to do with lactate. Let’s go deeper into the subject.


Extreme physical efforts, such as a sprint or very intense Freeletics workouts, require an immediate release of anaerobic energy. This means that the energy is produced without oxygen. Then the carbohydrates (glucose) are broken anaerobically. Do you wonder why? When we are exerting an extreme effort, the cells of the muscles of the body are not able to channel in the amount of oxygen they need to synthesize ATP. Therefore, the generation of anaerobic energy comes into play, since it does not need oxygen. What role does lactate have here? Lactate is a converted glucose molecule that is channeled out from the muscle cells to the blood. Why? Lactate can not be further separated in the absence of oxygen. For that reason the muscles ‘burn’ or even stop working completely. After making the effort, for example when you pause during workouts, in an interval training or after a sprint, the lactate is then channeled back to the cells. There it is degraded in an aerobic way when using oxygen.
The power supply for a continuous and immediate effort

With a sufficient supply of oxygen your body degrades glucose and also lactate completely to the final product of aerobic glycolysis (decomposition of glucose in ATP): water and carbon dioxide. The body normally uses aerobic energy generation when you pause during an interval, during a quiet run or when doing a gentle workout.

Lactate is not only your enemy but also a friend
If it causes a lot of pain, surely lactate can not be good, right? Actually, there is more lactate than this! Here we explain two positive effects:
• Studies have shown that lactate can have a positive impact on the regeneration of blood vessels as well as wound healing.
• Lactate allows sports scientists to discover physical performance.
Let’s summarize
It may hurt, but it is important to keep in mind that every time you do a workout and reach your individual limit, it will increase little by little and it will be more difficult to reach. Your individual limit is bound to be the border until you can continue without having lactate throughout the body. You will be putting in the form of a workout to another. As a free athlete, you know that everything is based on getting fit and that’s why you should continue to be faster, get fitter and stronger than the day before.

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