Acclimatization is the adaptation of living organisms to some new
clymatic and geographical conditions which they are not used to

   Without acclimatization preparation there will certainly arise problems while making any ascent, especially on the altitude over 5000 miters. Altitude influence is felt by almost everybody already in the first days after getting to the level of 1500-2000 miters, but the main symptoms can be clearly seen after 2500-3000 miters. They are: headache, sickness, vomiting (a so-called altitude disease) . Apart from that the organism which is not prepared for the lack of oxygen is more easily susceptible to different diseases, the working ability of a mountain-climber decreases considerably and his strong will almost aren't able to show themselves. Very often such symptoms can be observed only during the descent, sometimes during stops and decrease in forward movement. But they disappear only after the lowering of altitude or after taking some medicine. As a rule, these symptoms disappear by the morning and a person needs a day's rest. Oxygen is necessary for all organs and tissues of human body during the metabolism. Its consumption is directly proportional to the activeness of the organism. The transportation of oxygen is carried out by red blood bodies called эритроциты which contain the substance called hemoglobin (oxyhemoglobin) which, due to the difference in the partial blood pressure and the pressure in alveolas, is saturated with oxygen and transport it all over the organism. That's why the decrease in the partial pressure of oxygen in the air (but not the general quantity of oxygen, which is the most wide-spread delusion) causes the decrease in the saturation of blood with oxygen. That's why the first reaction (the first stage)of the organism on the decrease of the outer pressure is the quickening of pulse, the increase of the blood pressure and the intensification of lungs' ventilation (so-called hyperventilation). There is the dilation of capillaries in the tissues of the organism and in the first place-in the muscles. Besides, the additional blood from spleen and liver is added to the circulation of the blood. Those are the compensatory processes taking place in the first stage of acclimatization, which comes to an end, as a rule, within 7-14 days.

  During the second stage of acclimatization the lack of oxygen starts influencing bone marrow, which starts producing the increased number of erythrocytes and adds them into the circulation of the blood. The amount of hemoglobin increases in the blood in such a way. A normal amount of red blood bodies in 1 c. mm. is about 4,5-5,0 mln. in a male organism and 4,0-4,5 mln. in a female one. During the period of acclimatization the number of red blood bodies increases up to 7,0 and even up to 8,0 mln. in 1 c. mm., which leads to the increase of hemoglobin. It is ascertained that the second stage of acclimatization completely ends within three weeks after the beginning of the route. It is this fact that must determine the planned duration of acclimatization period and influence the tactics of acclimatization. You can reach a great altitude only after full adaptation. From physiological point of view the best scheme is to gradually reach a little bit higher altitude each time you ascend carrying the load with you (it's better to reside for a short period of time on the altitude you have reached, for example to spend the night there) and to alternate it with the descent in the base camp. The residence and the rest in the base camp 1 or 2 days renew your strength and secure a gained acclimatization keeping a certain balance between acclimatization and deterioration-the exhaustive emaciation of the organism, although a mountain-climber will never reach the level of his capacity for work in the plain conditions. So, it is necessary for a mountain-climber to strive for reaching a very high capacity for work in the plain conditions, better - in the middle-height conditions. You cannot acquire it in one year. It is developed, as a rule, through a general and special physical and functional training lasting many years (depending on the genetic peculiarities of the organism) which is accompanied by a regular and periodical medical checking (with a profound checking in a health centre each year) and by a constant self-control of your health (your pulse after you awake, your weight, etc.). As shows the experience of high-altitude expeditions, it is good to have a 2- or 4-day rest on the altitude of 500-1000 m. lower that the base camp after the pitching of intermediate and storming camps for the purpose of restoring your strength and keeping the results of acclimatization gained before. According to modern views 5300 m. is the boundary of high-altitude zone, in which a complete acclimatization may take place. Within the interval of 7000- 7800 m. you cannot speak about a complete and full acclimatization, and that's why your organism starts spending its own reserves without the possibility to replenish them. A mountain-climber can be in this zone up to the limit of 4-5 days, and after that it is necessary to descend lower. The zone higher than 7800 m. is called "the zone of altitude death". The staying in this zone for 2-3 days without the oxygen appliance causes a quick deterioration. While working out the strategy and tactics of a high-altitude ascent without the oxygen appliance one must take into account all said above.