What happens to your body when you work out?

  • During exercise, the heart pumps more blood to the muscles, increasing the heart rate.
  • The body increases oxygen supply, converting glycogen to energy and shedding heat and byproducts.
  • Regular exercise offers benefits such as improved mood, normal weight, cardiovascular health, diabetes resistance, and dementia prevention.


We have always told you about the effects of running and exercise on the mind and the (very often pleasant and welcome) consequences on your body. What happens, however, on a physical level while you are training?
Many processes within it change to adapt and respond to a condition that requires more effort, and knowing what they are helps you understand what is happening to you and why.

Let’s see them, step by step.

1. During training

In the early stages of training, the body behaves like a machine that has to power some of its parts to enable them to respond to a change in exercise conditions: if at rest the legs are for getting up or sitting down or moving for short stretches, during training their demand for energy increases. How are they provided? Initially through ATP (i.e., adenosine triphosphate), which provides immediate energy to sustain the sudden increase in load on the muscles.
This supply lasts only a few minutes. Next, oxygen intervenes, which, having reached the muscles through blood pumped in adequate quantities by the heart, converts glycogen into glucose, providing another source of energy. This is the aerobic phase (i.e., in the presence of oxygen).

The most trained professional athletes and amateurs can count on a heart that is more ready to increase the effort to get as much oxygen through the blood to the muscles as possible. Given the level of training, it is estimated that professionals can fill their muscles with blood (and thus oxygen) at levels twice as high as people their own age but untrained. It is, in other words, the famous V02max.

Another consequence of these early stages is an increase in the temperature of the muscles due to the oxygen exchanges that occur there and sweating, which is a thermoregulatory process that serves to exchange heat with the air so that the muscles do not exceed certain temperature thresholds. These also, due to exertion, become micro-injured. Because of this and also because of the accumulation of lactic acid during training, one consequence is a general soreness of the muscles, or at least those most subjected to exertion.

2. After training

One consequence already mentioned is muscle fatigue (and here we explain how to speed up recovery) but in the stages following the workout, it is your mind that benefits the most: thanks to the production of substances (very legal, you produce them!) improves your mood, some forms of weak depression can be contained or overcome, you invigorate your ability to concentrate and your creativity.

At the physical level and due to weight loss from a continuous and prolonged exercise regimen, blood pressure drops and the heart is therefore less stressed, and also, as shown, the very dangerous insulin resistance is also kept in check.

We are used to seeing the more obvious and external effects of training, such as muscle tone or weight loss, while it is less well known how and why this happens. As you may have realized by now, it all starts from a very small level, and that is cellular.

From such small units your body begins to change, gradually adapting to physical regimens that are more demanding but, even for that, more useful for being “fit,” in the sense of “fit to do something.” And the great thing is that by training, you are not only progressively more and more fit to run, but you are also fit with respect to life more generally: you load your heart less, you breathe better, you experience a condition of increased mental well-being.

And it all started from a simple thing that you learned to do as a child and then forgot how to practice, and that was running.
From the small of cells to the whole of your body and mind. And all thanks to physical activity.

(Via Psychology Today)


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