In last month’s post we were talking about the physical characteristics that we find at altitude and how it affects our training.

In this second part, we will talk about the physiological changes to which our body is subjected and how it can affect the time of scheduling our training when we stay at altitude. Obviously, the responses and adaptations suffered by the body are many and complex, we will focus on explaining some basic ones and obtaining a good understanding of them.

When we talk about altitude there are several things that must be taken into account to know the responses that our body is going to suffer. The two fundamental aspects that will influence this answer are the height and the time that we remain at that height.

In this document we will talk about the changes in ventilatory, cardiovascular and muscular responses in a basic way and try to explain what changes they suffer.

Ventilatory response: This ventilation or lung frequency is increased both during exercise and at rest.

At altitude, performance decreases since VO2 max is also decreased. Over time, VO2 max can increase but never reach the values ​​that we obtain at sea level.

This is because at altitude, for each breath we take we introduce fewer O2 molecules and therefore we need to breathe a greater number of times to supply the same amount of O2.

This response is activated when the carotid oxygen receptors detect a drop in O2 in the blood and activate the respiration mechanism.

Cardiovascular response: From the first hours the plasma volume begins to decrease progressively. In addition, cardiac output increases in the initial hours and decreases as we acclimate to altitude, but like VO2 it never returns to baseline values ​​that we have at sea level.

This is due in part to the loss of water that we suffer through respiration due to the need to equalize the humidity of the air that we have in the lungs with that we introduce from the outside.

On the other hand, exposure to heights increases the release of erythropoietin, the hormone responsible for the release of erythrocytes (red blood cells). In a chronic way, we get the body to increase the capacity to transport oxygen to our muscles.

These two causes generate thicker blood and make the heart also have to work harder to be able to mobilize it.

Muscular system: The modifications in this system are more durable than in the rest and are decisive for our performance.

In this case, exposure to hypoxia stimulates capillarity, so altitude helps us improve the capillary density of our entire muscular system. This change improves the supply of O2 that we can achieve in our muscles, notably improving performance.

In addition, the increase in capillaries helps us eliminate waste substrates such as lactic acid, reducing fatigue and improving recovery.

It is clear that when we are at altitude our performance in some type of tests such as resistance can be diminished. Stays at altitude and the changes our body undergoes will help us to perform once our stay is over.

Finally, in the last chapter on altitude training we will talk about the minimum times that the stays must have in order to obtain a benefit, the phases of altitude training and the training strategies that we can carry out.