The following is the impact of high altitude on training:
(a) Pulmonary Ventilation: Pulmonary ventilation is increased at higher altitudes. troth at rest and during exercise. Since the air at higher altitude is less dense, the increase in ventilation is compensatory mechanism to bring the same number of molecules of oxygen into the lung as an individual would take in at sea level. Since the number of molecules of oxygen for a given volume of air is less at higher altitude, an additional volume of air is necessary to supply the same to number of molecules of oxygen. The increased ventilation acts much the same as hyperventilation sea level, in that the CO2 in the alveoli is reduced, causing more CO2 to diffuse from the blood which results in an increase in pH of the blood.
(b) An Enlarged Haemoglobin Concentration in the Blood: In this acclimatization an increase the number of red blood cells causes rapid production of these cells by the bone marow haemoglobin concentration also increases and this increase is due to the overall decreases in plastic volume. The formation of many new cells is a slow process requiring at least several weeks to help acclimatize a person to high attitudes.
(c) Greater Diffusing Capacity of the Lungs: The normal diffusing capacity for oxygen through pulmonary membrane increases during exercise at sea level or at high altitude. This increase is due an augmented pulmonary capallary blood volume, which expands the capillaries and increases surface through which oxygen can diffuse into the blood and augment lung volume, which presumes expands the surface area of the alveolary membrane.
(d) An increased vascularity of the Tissues: In this the increase in the number of capillaries along a better distribution of blood to the areas such as the muscles, heart. brain and other organs that normally require large amounts of oxygen increases where gas exchange is needed tor optimal performance. The haemoglobin molecule comes into much closer contact with the active tissue cells and provides a supply of oxygen to each cell even with a somewhat lower oxygen tension.
(e) An increased Myoglobin Content of the muscles: There is also an increase in myoglobin, the oxygen carrying pigment in the muscle. With prolonged stay at altitude, the myoglobin concentration in both the heart and the skeletal muscles increases, which favours acclimatization at high altitude.
(f) A Greater Ability of the cells to adjust to the low partial pressure of oxygen and make use of the available oxygen: Human beings, who are native to high altitude have a greater number of certain cellular oxidative enzyme systems than those individuals who live at sea level. The naturally acclimatized individuals can survive for several hours at high altitudes without needing of much oxygen. Once a person returns to sea level following several weeks stay at high altitude, all of the physiological changes brought about by acclimatization will be lost within a period of about two weeks.
