Find out what influences adaptation to hypoxia and how you can increase resistance to hypoxia without harming the body. The adaptation of the human body to hypoxia is a complex integral process in which a large number of systems are involved. The most significant changes occur in the cardiovascular, hematopoietic and respiratory systems. Also, an increase in resistance and adaptation to hypoxia in sports involves the restructuring of gas exchange processes.
The body at this moment reorganizes its work at all levels, from the cellular to the systemic. However, this is only possible if the systems receive integral physiological responses. From this we can conclude that an increase in resistance and adaptation to hypoxia in sports is not possible without certain changes in the work of the hormonal and nervous systems. They provide fine physiological regulation of the whole organism.
What factors affect the adaptation of the body to hypoxia?
There are a lot of factors that have a significant impact on increasing resistance and adaptation to hypoxia in sports, but we will note only the most important ones:
- Improved ventilation of the lungs.
- Increased output of the heart muscle.
- An increase in the concentration of hemoglobin.
- An increase in the number of red cells.
- An increase in the number and size of mitochondria.
- Increase in the level of diphosphoglycerate in erythrocytes.
- Increased concentration of oxidative enzymes.
If an athlete trains in high altitude conditions, then a decrease in atmospheric pressure and air density, as well as a drop in the partial pressure of oxygen, are also of great importance. All other factors are the same, but still secondary.
Do not forget that with an increase in altitude for every three hundred meters, the temperature drops by two degrees. At the same time, at an altitude of one thousand meters, the strength of direct ultraviolet radiation increases by an average of 35 percent. Since the partial pressure of oxygen decreases, and hypoxic phenomena, in turn, increase, then the concentration of oxygen in the alveolar air decreases. This suggests that the tissues of the body are beginning to experience a lack of oxygen.
Depending on the degree of hypoxia, not only the partial pressure of oxygen decreases, but also its concentration in hemoglobin. It is quite obvious that in such a situation, the pressure gradient between the blood in the capillaries and tissues also decreases, thereby slowing down the processes of oxygen transfer into the cellular structures of tissues.
One of the main factors in the development of hypoxia is a drop in the partial pressure of oxygen in the blood, and the saturation indicator of its blood is no longer so important. At an altitude of 2 to 2.5 thousand meters above sea level, the indicator of maximum oxygen consumption drops by an average of 15 percent. This fact is precisely associated with a decrease in the partial pressure of oxygen in the air that the athlete inhales.
The point is that the rate of oxygen delivery to tissues directly depends on the difference in oxygen pressure directly in the blood and tissues. For example, at an altitude of two thousand meters above sea level, the oxygen pressure gradient drops by almost 2 times. In high-altitude and even mid-altitude conditions, the indicators of the maximum heart rate, systolic blood volume, oxygen delivery rate and cardiac muscle output are significantly reduced.
Among the factors affecting all of the above indicators without taking into account the partial pressure of oxygen, which leads to a decrease in myocardial contractility, a change in fluid balance has a great influence. Simply put, the viscosity of the blood increases significantly. In addition, it must be remembered that when a person enters the conditions of high mountains, the body immediately activates adaptation processes to compensate for the oxygen deficiency.
Already at an altitude of one and a half thousand meters above sea level, the rise for every 1000 meters leads to a decrease in oxygen consumption by 9 percent. In athletes who do not have adaptation to high altitude conditions, the resting heart rate can increase significantly already at an altitude of 800 meters. Adaptive reactions begin to manifest themselves even more clearly under the influence of standard loads.
To be convinced of this, it is enough to pay attention to the dynamics of the increase in the level of lactate in the blood at different heights during exercise. For example, at an altitude of 1,500 meters, the level of lactic acid rises by only a third of the normal state. But at 3000 meters, this figure will already be at least 170 percent.
Adapting to hypoxia in sports: ways to increase resilience
Let's look at the nature of the reactions of adaptation to hypoxia at various stages of this process. We are primarily interested in urgent and long-term changes in the body. At the first stage, called acute adaptation, hypoxemia occurs, which leads to an imbalance in the body, which reacts to this by activating several interrelated reactions.
First of all, we are talking about accelerating the work of systems whose task is to deliver oxygen to tissues, as well as its distribution throughout the body. These should include hyperventilation of the lungs, increased output of the heart muscle, dilation of cerebral vessels, etc. One of the first responses of the body to hypoxia is an increase in heart rate, an increase in blood pressure in the lungs, which occurs due to spasm of arterioles. As a result, a local redistribution of blood occurs and arterial hypoxia decreases.
As we have already said, in the first days of being in the mountains, the heart rate and cardiac output increase. In a few days, thanks to increased resistance and adaptation to hypoxia in sports, these indicators return to normal. This is due to the fact that the ability of the muscles to utilize oxygen in the blood increases. Simultaneously with hemodynamic reactions during hypoxia, the process of gas exchange and external respiration changes significantly.
Already at an altitude of a thousand meters, there is an increase in the ventilation rate of the lungs due to an increase in the respiratory rate. Exercise can greatly speed up this process. The maximum aerobic power after training in high altitude conditions decreases and remains at a low level even if the concentration of hemoglobin increases. The absence of an increase in BMD is influenced by two factors:
- An increase in the level of hemoglobin occurs against the background of a decrease in blood volume, as a result of which the systolic volume decreases.
- The peak of the heart rate decreases, which does not allow an increase in the BMD level.
The limitation of the BMD level is largely due to the development of myocardial hypoxia. It is this that is the main factor in reducing the output of the heart muscle and increasing the load on the respiratory muscles. All this leads to an increase in the body's need for oxygen.
One of the most pronounced reactions that are activated in the body in the first couple of hours of being in a mountainous area is polycythemia. The intensity of this process depends on the height of the stay of the athletes, the speed of ascent to the guru, as well as the individual characteristics of the organism. Since the air in hormonal regions is drier in comparison with the flat, then after a couple of hours of stay at an altitude, the plasma concentration decreases.
It is quite obvious that in this situation the level of red blood cells increases in order to compensate for the oxygen deficiency. The very next day after climbing the mountains, reticulocytosis develops, which is associated with the increased work of the hematopoietic system. On the second day of stay in high altitude conditions, erythrocytes are utilized, which leads to an acceleration of the synthesis of the hormone erythropoietin and a further increase in the level of red cells and hemoglobin.
It should be noted that oxygen deficiency in itself is a strong stimulant of the erythropoietin production process. This becomes apparent after 60 minutes of staying in the mountains. In turn, the maximum rate of production of this hormone is observed in a day or two. As resistance increases and adapts to hypoxia in sports, the number of erythrocytes increases sharply and is fixed at the required indicator. This becomes a harbinger of the completion of the development of the state of reticulocytosis.
Simultaneously with the processes described above, the adrenergic and pituitary-adrenal systems are activated. This, in turn, contributes to the mobilization of the respiratory and blood supply systems. However, these processes are accompanied by strong catabolic reactions. In acute hypoxia, the process of resynthesis of ATP molecules in mitochondria is limited, which leads to the development of depression of some functions of the main body systems.
The next stage of increasing resistance and adaptation to hypoxia in sports is sustainable adaptation. Its main manifestation should be considered an increase in the power of a more economical functioning of the respiratory system. In addition, the rate of oxygen utilization, the concentration of hemoglobin, the capacity of the coronary bed, etc. increases. In the course of biopsy studies, the presence of the main reactions characteristic of the stable adaptation of muscle tissues was established. After about a month of being in hormonal conditions, significant changes occur in the muscles. Representatives of speed-strength sports disciplines should remember that training in high altitude conditions involves the presence of certain risks of destruction of muscle tissue.
However, with well-planned strength training, this phenomenon can be completely avoided. An important factor for the adaptation of the body to hypoxia is a significant economization of the work of all systems. Scientists point to two separate directions in which change is taking place.
In the course of research, scientists have shown that athletes who have managed to adapt well to training in high altitude conditions can maintain this level of adaptation for a month or more. Similar results can be obtained using the method of artificial adaptation to hypoxia. But one-time training in mountain conditions is not so effective, and, say, the concentration of erythrocytes returns to normal within 9-11 days. Only long-term preparation in mountain conditions (over several months) can give good results in the long term.
Another way to adapt to hypoxia is shown in the following video: