When it comes to medium to high-intensity exercise, it is very common to hear about muscle fatigue, that annoying pain that doesn’t seem to go away and makes the muscle stops contracting and then fails.

To understand what fatigue really is, let’s start with the definition: muscle fatigue is the diminished ability to generate muscle strength or power during muscle contractile activity. Explaining in practice, it is that last repetition of the training that the arm shakes when we lift the dumbbell and feel that unbearable pain and burning or when we are simply running and the legs no longer obey us and weigh a ton.


Muscle fatigue and moderate-intensity exercises

In more prolonged and moderate-intensity exercises, intramuscular and hepatic glycogen is responsible for keeping our blood glucose levels stable, preventing a sudden drop of it. However, as the exercise extends, glycogen stores fall and fatigue sets in.

For this reason, it is recommended that in prolonged exercises, glucose supplementation or glycogen sparing agents be performed. Some studies indicate that caffeine taken in doses of 3-9 mg/kg 30 to 90 minutes before exercise can have this effect and increase aerobic capacity.


Muscle fatigue and high-intensity exercises

When it comes to more intense and shorter physical exercises, the mechanism of fatigue is different. Although lactic acid is pointed out as the main cause, today we already know that in fact, it is not. The increase in acidity within the cell is what generates a decrease in energy production and consequently loss of muscle contractility strength.

There is an indication of the use of supplements that attenuate the process of muscle acidity, such as sodium bicarbonate.

How to prevent muscle fatigue?

As we exercise constantly, our body is in a continuous process of breaking and repairing. For this reason, it is essential that we have a period of body rest so that we can restore our energy reserves and the body repair muscle fibers.

When training excessively and having inadequate rest, a syndrome known as “overtraining” can occur, where the athlete has a decrease in performance with increased fatigue motivated by metabolic, immunological or hormonal disorders.

With so many changes, fatigue is installed in a way that impairs performance in training or even in daily activities. Therefore, always remember: training intensively in pursuit of our goals, whatever they are, is valid and effective. However, we must not neglect rest, good nutrition and periodization of training. As we always say, evolution is a process – for some it is slow, for others it is faster.

To adjust your diet, your metabolism and your training, look for a doctor, nutritionist and a physical educator to help you. A good athlete is a conscious athlete!


See you on the mats,
Gracie Humaita Sydney.

By Fernanda Monteiro.


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