Training in the mountains

Part Three

TRAINING IN THE MOUNTAINS IS USED MAINLY FOR THE FOLLOWING REASONS:

improve the ability to use oxygen (via oxidation): training at sea level and recovery at sea level;
to improve the oxygen transport capacity: stay on the high ground (21-25 days) and qualitative training at sea level;
to improve aerobic capacity: training at altitude for 10 days.

CHANGES DUE TO STAY AT HIGH ALTITUDE:

increased resting heart rate
increase in blood pressure during the first few days
endocrinological adaptations (increased cortisol and catecholamines)

Athletic performance at high altitude

Given that the main purpose of training at altitude is the development of performance, at the center of this training there must be the development of basic endurance and resistance to strength / speed: however, it is necessary to ensure that all training methods applied are aimed in the direction of "aerobic shock".
With the exposure to high altitude there is an immediate reduction of VO2max (about 10% every 1000m of altitude starting from 2000m). On the summit of Everest the maximum aerobic capacity is 25% above sea level.

The resistance of the air is the set of forces that oppose the movement of a body in the air itself. Being in direct relationship with the density of the air, the resistance decreases as the altitude increases, and this has advantages in speed sports, because part of the energy expended to overcome the air resistance can be used for muscular work.

For prolonged performances, especially aerobic ones (cycling), the advantage deriving from the reduction of the resistance opposed by the air is more than offset by the disadvantage due to the reduction of VO2max.
Air density decreases with increasing altitude because atmospheric pressure decreases, but it is also influenced by temperature and humidity. The decrease in air density as a function of altitude has positive effects on respiratory mechanics.

The lactic acid work must be carried out over short distances, with speeds equal to or greater than the race pace and with longer recovery breaks than those carried out at low altitude. Load peaks and high lactic acid stresses must be avoided. At the end of the stay at high altitude, one or two days of mild aerobic work should be planned. It is necessary to avoid mixing training for aerobic power with lactic acid training, as two opposite effects are generated and at the expense of adaptation. After intensive loads, mild aerobic capacity workouts must be continuously introduced. In the acclimatization phases, do not apply high workloads.
Daily training checks must be carried out in order to: body weight, heart rate at rest and in the morning; control of training intensity by heart rate monitor; subjective evaluation of the athlete.
The positive effects can be assessed seven to ten days after returning from altitude. Preparing for an important race should never be preceded by altitude training done for the first time.
At altitude, the amount of carbohydrates in the daily diet is important: it must be equal to sixty / sixty-five percent of the total calories. In hypoxia the body requires more carbohydrates on its own because it must keep the oxygen requirement low.
A "rational diet with an adequate supply of fluids are essential conditions for a fruitful training at high altitude.

HIGH LEVEL COMPETITION

In the face of a physiological literature rich in data concerning work at high altitude with the results resulting from acclimatization, the indications aimed at establishing the general fitness (or aptitude) to practice sporting activities of intense competitive commitment in the environment appear to be reduced or non-existent. similar or only slightly lower in height.
A typical example is the Mezzalama Trophy, established about fifty years ago to perpetuate the memory of Ottorino Mezzalama, absolute pioneer of ski-mountaineering: this race, now in its 16th Edition, unfolds on a highly suggestive and extremely demanding course, which goes from Plateau Rosa di Cervinia (3300 m) to the Gabiet Lake of Gressoney-La Trinité (2000 m), through the snowfields of the Verra, the peaks of the Naso del Lyskamm (4200 m) and aided and cramped sections of the Rosa group.
The altitude factor and intrinsic difficulties create a big problem for the sports doctor: which athletes are suitable for this race and how to evaluate them a priori to reduce the risks of a race that mobilizes hundreds of men to trace the path and guarantee rescue in this race. can it really be called a challenge to nature?
The Institute of Sports Medicine of Turin, in evaluating more than half of the competitors (about 150 also from outside Europe), has developed an operational protocol based on clinical and anamnestic, laboratory and instrumental data. the stress test: a transporter ergometer and closed-loop spirometer was used, with an initial load at sea level in O2 at 20.9370, then repeated at a simulated altitude of 3500 m, obtained by reducing the percentage of O2 in the air of the spirometric circuit, up to 13.57% corresponding to a partial pressure of 103.2 mmHg (equal to 13.76 kPa).
This test allowed us to introduce a variable: that of "adaptation to altitude. In fact, all the routine data did not give significant modifications or alterations for the athletes examined, allowing us only one general suitability judgment: with the aforementioned test it was possible to analyze the behavior of the pulse of 02 (relationship between consumption of 02 and heart rate, index of cardio-circulatory efficiency), both at sea level and at altitude. The variation of this parameter for the same workload, ie the extent of its decrease in passing from normoxic conditions to an acute state of hypoxia, allowed us to draw up a table to define the aptitude for working at height.
This attitude is all the greater, the smaller the decrease in the pulse of O2 passing from sea level to altitude.
It was considered reasonable, in order to grant the eligibility, that the athlete does not present reductions in excess of 125%. For more marked reductions, in fact, the safety on the state of global physical efficiency appears at least doubtful, even if there remains the uncertainty of an exact definition of the most exposed district: heart, lungs, hormonal system, kidneys.

HYPOXIA AND MUSCLES

Whatever the responsible mechanism, the reduced arterial oxygen concentration determines in the organism a whole series of cardio-respiratory, metabolic-enzymatic and neuro-endocrine mechanisms, which in more or less short times lead man to adapt, or rather, acclimatize to the altitude.

These adaptations have as their main objective the maintenance of "adequate tissue oxygenation. The first responses are in the cardiorespiratory system (hyperventilation, pulmonary hypertension, tachycardia): having less oxygen available per unit of air volume for the same job," more ventilation is needed, and by carrying less oxygen with each stroke, the heart must increase the rate of contraction to deliver the same amount of O2 to the muscles.
The reduction of oxygen at the cellular and tissue level also induces complex metabolic modifications, of gene regulation, and release of mediators. An extremely interesting role is played, in this scenario, by the oxygen metabolites, better known as oxidants. , which act as physiological messengers in the functional regulation of cells.
Hypoxia represents the first and most delicate problem of altitude, since from the average altitude (1800-3000 m), it causes adaptive modifications in the organism that is exposed to it, the more important the higher the altitude.

In relation to the time spent at altitude, acute hypoxia is distinguished from chronic hypoxia, since the adaptive mechanisms tend to change over time, in an attempt to reach the most favorable equilibrium condition for the organism that is exposed to hypoxia. Finally, to try to keep the oxygen supply to the tissues constant even in hypoxic conditions, the body adopts a series of compensation mechanisms; some appear rapidly (eg hyperventilation) and are defined as adjustments, others require longer times (adaptation) and lead to that condition of greater physiological balance which is acclimatization.
Reynafarje in 1962 observed on biopsies of the sartorius muscle of subjects born and residing at high altitudes that the concentration of oxidative enzymes and myoglobin was higher in those born and residing at low altitudes. This observation served to establish the principle that tissue hypoxia is a fundamental element of the adaptation of skeletal muscles to hypoxia.
An indirect proof that the reduction of aerobic power at altitude is not only caused by the reduced quantity of fuel but also by the reduced functioning of the engine, comes from the measurement of the VO2max at 5200 m (after 1 month of stay) during the administration of O2 such as to recreate the condition at sea level.
But the most interesting effect of the adaptation due to staying at altitude is the increase in hemoglobin, red blood cells and hematocrit, which allow to increase the transport of oxygen to the tissues. The increase in red blood cells and hemoglobin would wait for a 125% increase from sea level, but the subjects only reached 90%.
The other apparatuses show adaptations that are sometimes not always certainly explainable. For example, from the respiratory point of view, the native at high altitude has less pulmonary ventilation under stress than the resident, even if acclimatized.
It is currently agreed that permanent exposure to severe hypoxia has detrimental effects on the musculature. The relative scarcity of atmospheric oxygen leads to a reduction of the structures involved in the use of oxygen which involves, among other things, the protein synthesis which is compromised.

The mountain environment presents disadvantageous living conditions for the organism, but it is above all the reduced partial pressure of oxygen, characteristic of high altitudes, which determines most of the physiological adaptation responses, necessary to at least partially reduce the problems caused by altitude.
The physiological responses to hypoxia affect all the functions of the organism and constitute the attempt to reach, through a slow process of adaptation, a condition of tolerance to altitude called acclimatization. By acclimatization to hypoxia s "means a condition of physiological equilibrium, similar to the natural acclimatization of the natives of regions located at high altitudes, which makes it possible to stay and work up to altitudes around 5000 m. At higher altitudes it is not possible to acclimatize and a progressive deterioration of the organism takes place.
The effects of hypoxia generally begin to manifest themselves starting from medium altitudes, with considerable individual variations, linked to age, health conditions, training and habits of staying at high altitudes.

The main adaptations to hypoxia are therefore represented by:

a) Respiratory adaptations (hyperventilation): increased lung ventilation and increased oxygen diffusion capacity
b) Blood adaptations (polyglobulia): increase in the number of red blood cells, changes in the acid-base balance of the blood.
c) Cardio-circulatory adaptations: increase in heart rate and reduction in systolic output.