Lactate: The reason behind burning muscles

Lacktat 1500x400

Ever wondered why your muscles burn during a demanding workout? This uncomfortable feeling – often the reason you want to quit – occurs when something called lactate is floating through our muscles. Here, we will explain what the so-called lactic acid ‘lactate’ is and how energy is generated under different physical strains.

Never heard of lactate?

When it comes to Freeletics workouts or a large amount of challenging repetitions such as 100 Burpees, 50 weighted back squats or a sprint, it’s all about giving it your all and trying to do it as fast as possible. One of the many factors contributing to a great time for a workout is the ability to endure the produced lactate. Lactate? Never heard of it? Lactate occurs when your body breaks down carbohydrates (glucose) under extreme physical strain. Every Free Athlete has already experienced what it means to have lactate “floating” through the body. Before we further explain what lactate is, we need to clarify some terms and processes that are of high importance to understand how lactate is produced within the body. First we will look at adenosine triphosphate – the human’s energy unit.

What is adenosine triphosphate (ATP) and how does it serve the human body?

Depending on the intensity and the duration of a workout, the energy demand of the human body or – more precise of the muscle cells – differs. In order to provide the cells with energy, your body burns carbs, fats and protein through different processes. The produced energy allows the muscles to contract. The energy is then provided to the body in the form of adenosine triphosphate (short: ATP), also known as the “energy currency” of the body.

The muscles are only able to store a very small amount of ATP. This is why ATP has to be synthesized over and over again. How the energy currency ATP is (re-)synthesized depends on the type of physical strain and on how much oxygen our cells are able to channel inside. It is a highly complex cycle with lots of metabolic by-products that is needed to synthesize ATP. One of those metabolic by-products is called lactate. It occurs in the so-called anaerobic energy generation. Mentioning the anaerobic energy production, you will most likely ask yourself what this is and what this has to do with lactate. Let’s dig deeper.

What happens under extremely hard and short strain?

Extreme physical strains – just like a sprint or highly intensive Freeletics workout – require an anaerobic immediate energy release. This means that the energy is produced without oxygen. Carbohydrates (glucose) are then broken down anaerobically. You wonder why? When our muscle cells are under extreme strain, they are not able to channel enough oxygen they need to synthesise ATP. Therefore, the anaerobic energy generation comes into play since it doesn’t need oxygen. What role does lactate play here? Lactate is a converted glucose molecule which is channelled out of your muscle cells into the blood. Why? Lactate can’t be broken down further without oxygen. This is why your muscles ‘burn’ or even completely fail to function. After the strain, for example when you pause during a workout, in an interval training or after a sprint, lactate is then channelled back into your cells. There it is degraded aerobically, so under the use of oxygen.

Energy supply for continuous and mediate strain

With a sufficient oxygen supply your body degrades glucose and also lactate completely until the end products of the aerobic glycolysis (breakdown of glucose into ATP): water and carbon dioxide. The body usually uses the aerobic energy generation when you pause during an interval, during a paced run or when you do a light workout.

Lactate is not only your enemy but also a friend

If it causes so much pain, surely lactate can’t be good right? Actually, there is more to lactate than this! Here are two positive side effects:

  • Research has shown that lactate can have a positive impact on the regeneration of blood vessels as well as on wound healing.
  • Lactate allows sports scientist to figure out your physical performance.

Let’s recap

It may hurt, but it’s important to keep in mind, that every time you do a workout and hit your individual threshold, it will increase step by step and become harder to reach. Your individual threshold is meant to be the border until you can go without having lactate everywhere in your body. You’ll get fitter from one workout to the next one. And as a Free Athlete, it’s all about this continuous improvement.