Acclimatization during ascents
Koxygen is necessary for all organs and tissues of the human body during metabolism. Its consumption is directly proportional to the activity of the body. The transfer of oxygen is carried out by red blood cells - erythrocytes containing a substance - hemoglobin (oxyhemoglobin), which, due to the difference in the partial pressure of oxygen in the blood and in the alveoli, is saturated with oxygen and transports it throughout the body. With altitude, the partial pressure of oxygen in the air decreases (and not the amount of oxygen in general, which is one of the widespread misconceptions), which causes a decrease in blood oxygen saturation. Therefore, the first reaction (first phase) of the body to a decrease in external pressure is an increase in heart rate, an increase in blood pressure and an increase in pulmonary ventilation (the so-called hyperventilation), which is actually the cause of headaches, etc. There is an expansion of capillaries in the tissues of the body and, above all, in the muscles. In addition, reserve blood from the spleen and liver is included in the blood circulation. These are compensatory processes that occur in the first phase of acclimatization, which usually ends after 7-14 days.
In the second phase acclimatization, the lack of oxygen begins to affect the bone marrow, which begins to produce an increased number of red blood cells and introduce them into the circulation. This increases hemoglobin in the blood. The normal number of red blood cells in 1 cubic mm is about 4.5-5.0 million in men and 4.0-4.5 million in women. During the acclimatization period, the number of red blood cells increases to 7.0 and even up to 8.0 million per 1 cubic mm, which leads to an increase in hemoglobin. It has been established that the second phase of acclimatization is completely completed three weeks after the start of work on the route. This is what should determine the planned duration of the acclimatization period and influence the acclimatization tactics. Reaching high altitudes can only be achieved reliably after full adaptation.
From a physiological point of view, the best system is to gradually reach higher altitudes with a load (preferably with a short stay at the achieved height, for example, spending the night), alternating with a descent down to the base camp. Staying and resting at the base camp for one or two days restores strength and consolidates the resulting acclimatization while maintaining a relative balance between acclimatization and deterioration - exhaustive exhaustion of the body, although the climber will never reach the level of his performance under flat conditions. Hence the need for the climber to strive to achieve very high performance in plain conditions, and better yet in mid-mountain conditions. You can't buy it in one year. It is developed, as a rule, by many years (depending on the genetic characteristics of the body) of training in general and special physical and functional training with regular periodic medical monitoring (including at least an annual medical examination for an in-depth examination) and daily constant self-monitoring of well-being (lying pulse after waking up, body weight, etc.).
As the experience of high-altitude expeditions shows, for better recuperation while maintaining the achieved acclimatization after completing the installation of intermediate and assault camps, a 2-4-day rest at an altitude of 500-1000 m below the altitude of the base camp is advisable. According to modern ideas, 5300 m is the boundary of the high-mountain zone, in which complete acclimatization may yet occur. In the range from 7000 to 7800 m, one cannot speak of complete acclimatization, so the body begins to use up its own reserves without the possibility of replenishing them. A climber can stay in this zone for up to 4-5 days, after which it is necessary to descend lower. The zone above 7800 m is called "altitude death zone" . Staying there for 2-3 days without an oxygen apparatus causes rapid deterioration. When developing a strategy and tactics for oxygen-free high-altitude ascent, it is advisable to take the above into account.
Nikolay Solovtsov, Candidate of Medical Sciences, Master of Sports,
Alexander Fomin, member of the FAiSU executive committee, master of sports
Alexander Fomin, member of the FAiSU executive committee, master of sports