Acclimatization in the mountains

When rising to altitude, atmospheric pressure, the partial pressure of oxygen in the atmosphere and pulmonary alveoli, as well as the saturation of hemoglobin with oxygen simultaneously decrease (98% of O2 in the blood is transported by red blood cells and only 2% by plasma). This can cause hypoxia (oxygen starvation) – a condition that occurs when there is insufficient supply of oxygen to tissues or disruption of its use in the process of biological oxidation. Close in meaning is the term hypoxemia – low oxygen content in the blood. Oxygen is necessary for the processes of oxidative phosphorylation (synthesis of adenosine triphosphate (ATP*); O2 deficiency disrupts the course of all processes in the body that depend on ATP energy: the work of cell membrane pumps transporting ions against the concentration gradient, the synthesis of mediators and high-molecular compounds – enzymes, receptors for hormones and mediators. If this occurs in the cells of the central nervous system, the normal course of the processes of excitation and transmission of nerve impulses becomes impossible.

There are also a number of diseases that prevent you from going on a serious hike or climb – you will find a detailed list here.

More details about such a condition as “Altitude sickness” in the article.

*The reason for the preference, under hypoxic conditions, for high-intensity exercise to obtain energy from carbohydrates rather than higher-calorie fats is the greater ATP yield: carbohydrates form 6.3 moles of ATP/mol O2; fats – 5.6 mol ATP/mol O2.

From the table above, a number of conclusions can be drawn:

• the decrease in partial pressure of air and, accordingly, oxygen from altitude occurs nonlinearly;
• the degree of saturation of the lungs with oxygen in relation to its content in the external air decreases (this may be due to an increase in the proportion of CO2 in the lungs, and in the “death zone” breathing is so intense that CO2 does not have time to accumulate in the lungs);
• hemoglobin is capable of being almost 100% saturated with O2 when its partial pressure in the lungs is 13-14% (!) of atmospheric;
• the degree of oxygen saturation of hemoglobin is not linear: even when the partial pressure of oxygen in the lungs is halved, hemoglobin will still be 80% saturated.

Thanks to the amazing property of hemoglobin to greedily absorb oxygen, even at low pressures, it becomes possible for a person to move and live in the highlands.

The lungs respond to a lack of oxygen by first breathing deeper (increasing its volume):

The degree of saturation of human hemoglobin with oxygen depends on altitude and the decrease in atmospheric pressure (respectively, the amount of oxygen) with altitude, and then with an increase in breathing frequency. With reduced air density, the mass of oxygen contained in it naturally decreases, i.e. there is a “decrease in the oxygen ceiling.”

Therefore, the oxygen supply to the body at high altitudes will be insufficient, and the theoretical power of the work performed will be determined by the degree of oxygen saturation of hemoglobin in the blood.

And ultimately determine the duration of acclimatization.

According to modern ideas, heights up to:

5300-5400 m – зона полной акклиматизации, когда отдых и питание полностью восстанавливают затраченную энергию здоровых людей;
5400-6000 m — zone of incomplete acclimatization (no complete recovery even with rest);
6000-7000 m — adaptation zone (the body’s compensatory mechanisms work with great tension and complete restoration of vitality, although difficult, is possible for a short time);
7000-7800 m — zone of partial, temporary adaptation (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);
over 7800 m — “high-altitude death zone” (staying in it for 2-3 days without an oxygen apparatus causes rapid deterioration (exhaustion).

Many people know about this. And yet I would like to draw attention to the fact that the indicated conditions in these high-altitude zones already imply that the climbers already have adequate acclimatization to these altitudes. By the way: the above graph explains why relatively complete rest is possible at altitudes of 4200-4400 m.

How to train for heights

When the partial pressure of air drops, the oxygen saturation of a person’s lungs during breathing decreases. As a result, oxygen starvation of various tissues of the body occurs. Which leads to a weakening of the processes of oxidation and reduction and other reactions in the process of human life. After which the general tone and performance of a person decreases (with prolonged fasting, loss of consciousness, swelling of the lungs and brain). In order to obtain the required amount of oxygen, we reflexively take more inhalations and exhalations, which leads to increased heart rate, further processes of fatigue and accumulation of lactic acid in the body, as a result of insufficient oxygen supply to the body and overload of the heart. The body, in order to obtain the necessary volume of oxygen for its vital functions, stimulates the heart to work more intensely, that is, it increases the frequency of contractions per unit time. But as we know, only trained athletes can work at a high heart rate for a long time, but one way or another the heart gets tired. Therefore, the way out of the situation is to increase the volume of the heart muscle, thats why the working volume of pumped blood per unit of time, at which the heart rate will remain unchanged or will change, but only slightly. Thus, we will be able to perform physical work at height for a long time without significant loss of ability to work.

We will not delve into the biochemical processes of the heart under various types of loads, in particular oxygen starvation of the body during intense physical activity and other adaptation processes within the body, which depend not only on the person’s fitness, but on the work of the body at the molecular, hormonal level (and these Each person’s indicators are individual, the Sherpa people of Nepal are, of course, initially more resistant to high-altitude climbs at the molecular and hormonal level, since they are born and live at an altitude of 4000-4500 m above sea level). But we know (as a result of research) that skiers (cross-country skiers) and long-distance runners are the most prepared for such types of loads. The reason for this is the larger volume of the heart relative to the total mass of a person (in wrestlers and jocks, the muscular volume of the heart is much lower than in track and field athletes and even lower than in non-athletes). This allows you to pump a larger volume of blood per unit of time at a certain heart rate, and thereby more intensely nourish the body’s tissues with oxygen, in conditions where there is little oxygen and a person performs physical activity. The heart is a muscle that has its own resource and endurance. Thus, the larger this muscle volume, and the more it is trained, the faster and better the adaptation occurs in high mountain conditions. The optimal training in the winter is skiing, and in the off-season – cross-country running. The lion’s share of the physical preparation of those who are going to high mountains should be devoted to these trainings. Not so long ago, scientists were debating what is the optimal balance of forces when running. Some thought it was variable, others thought it was uniform. It really depends on your training level.

To increase heart volume, long-term training is used not at the maximum heart rate, but at a pulse corresponding to the maximum stroke volume.

«Long-term training at maximum stroke volume is, relatively speaking, “flexibility” exercises for the heart. The muscles pump blood, and the heart begins to stretch with this flow of blood. Traces of such stretching remain, and gradually the heart increases significantly in volume. It can be increased by 2 times, and by 35-40% is almost guaranteed, since the heart is a “hanging” organ, unlike skeletal muscles, and stretches quite easily. The decrease in heart rate in endurance athletes is compensated by an increase in systolic volume. If in an untrained person at rest it averages about 70 ml, then in highly qualified athletes (with a resting heart rate of 40-45 beats/min) it is 100-120 ml.
And if the heart is severely hypertrophied, then the heart rate can drop to 40-42 and even 30 beats/min. Such a pulse was, for example, the Finnish runner, winner of the 70s Olympics, Lasse Viren. Along with running, he and other Finnish athletes included walking uphill with long, long strides, with a pulse of 120. Such walking uphill for several hours leads to stretching of the heart and recruitment of muscle fibers into “oxidative” ones (from IIb they turn into IIa-type ).
 If you need to increase the stroke volume of the heart by 20%, then you need to train at least 3-4 times a week for 2 hours (at a heart rate of 120-130 beats/min, at which the maximum stroke volume is achieved). If you need to increase 50-60%, then you need to train 2 times a day for 2 hours, at least 3-4 days a week. To achieve 100% hypertrophy, that is, to make the heart 2 times larger, very large volumes are already required. This is every day for 4, 5 hours. Such training should be continued for about 4-5 months. After this, the person will simply have a stretched heart. Moreover, this state will be quite easy to maintain.»

For those who have not yet reached the professional level, in order not to overwhelm your body and avoid severe fatigue, at first it is worth starting with short distances of 3 km and in two weeks of training increase the duration to 5-6 km – 2-3 times a week. Then, as soon as you get stronger, reach the given level of training 3-4 times a week with a given duration.

These recommendations are given for climbing above 5600-6000 m altitudes. When planning to climb Elbrus, you must arrange your training schedule in such a way that you run for at least 10 km, and the total duration is at least 1 hour, excluding warm-up and other exercises to develop general physical endurance.

IMPORTANT NOT TO GO TO THE MOUNTAINS OVERTRAINED!!!

The last month before departure should focus on recovery:

• proper sleep, good nutrition, increasing hemoglobin, healing old injuries, teeth, etc.;
• peak of fitness form must be achieved at least 1 month before leaving for the mountains;
• further training before leaving should be reduced, in my opinion, to recreational jogging of 5-6 km, every day be sure to walk at least another 8 km – this will bring the body closer to hiking mode;
• In the last 7-10 days before departure, races should be completely excluded.

In general, it should be said that great athletes, especially those with insufficient high-altitude experience (low, short, with a break in the seasons) in the mountains are four times at risk due to:

• incorrect reaction of the body to altitude;
• vulnerable immunity;
• states of overtraining;
• completely different expectations of their role in the group for themselves and for others.

We need to remember this. As well as about the danger of “hardening” and swimming on the routes, and about eating snow. Messner always remembered his “weak throat.” And many novice high-altitude climbers don’t even realize that sometimes one or two hundred seconds are enough for hypothermia in the mountains when demonstrating a wet back, open throat, and lack of a hat. 40% of the body’s heat is produced in the head; there is no better way to quickly release it than to walk without a hat. According to the laws of physics, a layer of sweat instantly evaporating in the wind takes away much more heat during this time than contact with cold water (one of the hardening methods is based on this principle – wiping with hot water, which requires great care and gradualness).

List of general and special contraindications for participation in high-mountain expeditions and ascents:

• diseases of the cardiovascular system and blood with hemodynamic disorders;
• pulmonary diseases with significant impairment of ventilation;
• endocrine diseases;
• diseases of the airways and lungs (tracheitis, bronchitis, pneumonia, pleurisy, acute pulmonary tuberculosis);
• acute infectious diseases of the ENT organs (rhinitis, tonsillitis, pharyngitis, sinusitis), polyps, otitis media, mastoiditis, etc.);
• acute infectious diseases of the gastrointestinal tract, chronic diseases of the abdominal organs, etc.;
• cardiovascular diseases (coronary heart disease, degenerative changes, rheumatic carditis, heart rhythm disturbances with ventricular extrasystole, etc.);
• mental disorders and neuroses, cerebral vasopathies with a tendency to vasospasms;
• organic diseases of the central nervous system, epilepsy, etc. – all forms of endatheritis;
• vein diseases;
• hypertonic disease;
• all forms of anemia.

Preventing iron deficiency anemia

If stocking up on most vitamins in advance, in advance, is mostly useless, then with regard to increasing the hemoglobin content, the opposite happens. In order to prevent iron deficiency anemia, iron consumption at least a month (at least 3 weeks) before the mountains should be increased in the diet due to:

• foods richest in easily digestible iron: meat, liver (especially beef). 6% of iron is absorbed from meat, from eggs and fish – 2 times less, and from plant foods – only 0.2%.;
• apples, spinach, currants, juices, porcini mushrooms;
• peas, beans, hazelnuts, chocolate;
• cereals: buckwheat, oatmeal; rye bread (many grains and vegetables are good sources of iron, but not heme iron. Although the body only absorbs a small percentage of this form of iron, eating such foods at the same time as meat can help improve its absorption);
• Consider the effect of calcium, tea and coffee. The large amounts of calcium and phosphorus contained in milk and cheese may somewhat interfere with the absorption of iron. Tannin in tea and coffee binds iron, preventing it from being absorbed. If you take both iron and calcium supplements, take them at different times. Do not drink tea or coffee immediately after meals.
• Combine foods rich in iron with foods high in vitamin C, which promotes iron absorption.
• use special supplements containing medicinal iron (a mandatory requirement for iron-containing preparations is the presence of folic acid and cyanocobalamin).

We can recommend:

HemoHelper (a concentrate of iron found in a heme form highly accessible to humans and a complex of essential amino acids);

Ferrum lek (chewable tablets);

Fenyuls (capsules).

The complex of iron with ethylenediamine-succinic acid has proven itself very well. What exactly does normal or increased hemoglobin content mean for mountains? According to my own feelings, it mainly softens the first days of staying at altitude. Is this not enough?