How does the body responds to exercise: Adaptation mechanisms

How does the body responds to exercise: Adaptation mechanisms<span class="wtr-time-wrap after-title"><span class="wtr-time-number">8</span> min read</span>

Exercise is a physical activity that is planned, structured, and repetitive for conditioning the body. It is important to understand how does the body responds to exercise to make the most of the activity and avoid injury.

The body responds to exercise in several ways, including an increase in heart rate, an increase in breathing, and an increase in blood flow. These response mechanisms are known as adaptation mechanisms, and they help the body cope with the demands of exercise.

In this article, we will take a closer look at the different adaptation mechanisms and how they help the body to respond to exercise.

What is adaptation?

The human body is a wonderful creation. All activities (physical, mental and spiritual) are developed in order to survive, live and reproduce. The most basic function of this primitive purpose is adaptation.

how does the body responds to exercise

Adaptation is the biological, chemical, and/or psychological reaction of the organism (body) to stimuli of the natural or social environment. In this way, the body prepares itself to better meet the new needs, that is, to survive in the new conditions.

The natural environment where human beings have evolved imposes many challenges, such as climatic changes, lack of food or water, diseases, etc. To survive in these conditions the human body must have mechanisms that allow it to adapt to them.

These mechanisms are very complex and involve different systems of the organism, such as the circulatory, respiratory or nervous systems. Thanks to them, human beings can adapt their physiology and behavior to changing environmental conditions and thus improve their chances of survival.

The different adaptation mechanisms

Adaptations are mainly divided into two categories, depending on the time in which they occur. Some occur in a short period (seconds, hours, or days) and others over a long period (months, years). An example of a short-term adaptation is tanning. It happens almost immediately and is completed within a few hours. On the other hand, an example of adaptation over a long period is to lose weight gradually, as a result of consuming less food. 

There are many examples of adaptation that fall into either category. For the sake of brevity, we will only discuss a few more here. Another example of a short-term adaptation is increased heart rate. This happens in response to exercise or fear and is crucial for supplying the muscles with oxygenated blood. A long-term adaptation might be developing muscle tissue in response to strength training. This process can take weeks or even months to complete. 

As you can see, many different types of adaptations can occur, depending on the situation. Whether they happen quickly or over time, they are all essential for helping us survive and thrive in our environment.

How the body responds to exercise

The body responds to exercise both with short and long-term adaptations. Immediate (short /acute) ones concern the reactions of the human body systems that occur automatically, for example, the increase of heartbeat. Long-term ones involve changes in the body, and related body systems, that occur over time, as a reaction to a repetitive exercise or movement.

Those of you who have trained, even a little, systematically, can remember any changes you noticed occurring via your initial contact with training. Indicatively, after a few weeks, you would have noticed a slight improvement in strength and the ability to produce more energy.

If you had followed a proper, quality diet, you would have seen these results even more intensely. In particular, after 5-6 weeks of continuous and systematic training and qualitative nutrition, some changes in body structure would be visible, perhaps with some improvement in the ratio of muscle mass versus adipose tissue.

How does the adaptation mechanism help the body to respond to exercise

  • When you exercise and create any movement in the body, this movement is due to the function of the skeletal muscles. Their contraction creates the strength and thus the desired outcome. Yet the muscles need the energy to function. Muscles use energy in the form of ATP (adenosinetriphosphate), to which food is eventually converted, following a process that involves several energy systems.
  • Our body must adjust its muscle fibers and energy systems to meet the demands of the activity. If the movements are explosive and fast, then the body will recruit type IIa muscle fibers, which are best suited for this type of activity.
  • At the same time, the body’s anaerobic energy system will be trained, as this is the system that is most efficient at providing energy in the absence of oxygen. However, if the activity exceeds 2 minutes, then the body will recruit type I muscle fibers and focus on training the aerobic energy system. This system is more efficient at providing energy over long periods. All the body’s energy systems adapt to a combination of movements.
  • When the body engages in aerobic activity, it goes through a variety of changes to become more efficient. One of the most notable changes is an increase in blood flow to the skin. This happens because the body is trying to cool down through sweat. In addition, the enzymes that produce ATP in the aerobic energy system become more active. This helps to increase the overall production of ATP, which is then supplied to the muscles. Together, these changes help to improve the capacity and endurance of the aerobic energy system, ultimately reducing fatigue.
  • During exercise, the body’s demand for oxygen increases, and the cardiovascular system must work harder to meet this demand. One of the ways it does this is by increasing the size of the left ventricle and the walls of the heart. This allows the heart to contract more strongly and pump more blood with each beat. The cardiovascular system also improves the resistance of the heart to high-pulse function and improves the walls of blood vessels. This helps to reduce shortness of breath and decrease blood pressure.
  • Exercise has a positive impact on the endocrine system, increasing the production of certain hormones and reducing the production of others. For example, exercise increases the production of growth hormone, testosterone, cortisol, and catecholamines. These hormones help the body to more efficiently use glycogen, which is stored in the muscles and liver. Exercise also reduces the production of insulin, which helps to improve blood sugar management. The positive effects of exercise on the endocrine system help to keep the body healthy and functioning properly.
  • Anyone who has ever played a sport knows that the more you do it, the easier it becomes. This is because your nervous system is constantly adapting to the demands of the activity. The changes that take place are mainly related to the responses of neurons by improving their sensitivity, ie. their ability to stimulate muscle cells more and more efficiently. This is also known as improving neuromuscular coordination and relates to the main ability of the central nervous system to control all muscles more efficiently. When you first start playing a sport, your nervous system is not very efficient at stimulating muscle cells, which results in a lot of wasted energy and poorer performance. However, with practice, your nervous system becomes better at timing the muscle contractions so that they are more coordinated and efficient. This results in less fatigue and improved performance. In other words, your nervous system adapts to the demands of the sport and becomes more efficient over time.


It’s amazing to think about all of the positive changes our bodies can undergo in such a short period, and even more so when we consider that these changes are only possible because of the adaptation mechanism. This process is responsible for making us stronger, faster, and better able to cope with physical stressors.

So the next time you’re feeling down about your workout routine, remember that all of those aches and pains are evidence that your body is changing for the better. Keep up the good work – you’re on your way to becoming a superhero!

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