It is not today that we have discovered the benefits of a period of training on rise, but that the first reports of a possible influence on the altitude of physics were already in Million by Marco Polo. The air we breathe is a mixture of gases present in constant percentage: 78% nitrogen, 21% oxygen, carbon dioxide 0.04% and inert gas such as argon, helium, ozone etc, that does

not alter the effect of altitude. It changes the partial pressure, and reduces with increasing altitude. This is why our organism has an insufficient supply of oxygen. With low levels of oxygen in the blood, less oxygen is available for tissues, leading to hypoxia, namely the reduction of oxygen in tissue. The low concentration of oxygen in the blood leads to a series of natural physiological adaptations; first, respiratory center increase ventilation. But this increase can not be excessive, a situation typical of persons not trained and is subject to a sudden rise in the share altitude, because if the pulmonary ventilation increases too much respect to the metabolic demand will be meeting at the hyperventilation, that is a frequent series of breaths, even up to 40 per minute, that does not lead to an increase in oxygen, but a substantial reduction of carbon dioxide in the blood, called respiratory alkalosis. This causes a reduction of acidity of the blood which in turn leads to an increase affinity hemoglobin, which is that less oxygen is released in tissues, but also a greater amount of oxygen that is linked to hemoglobin in the lungs. With the passing of the days in high altitude kidneys with increased production of bicarbonate report valued the stability of acid-base balance and then begin to secrete the hormone erythropoietin, which stimulates the synthesis of red blood cells, resulting in an increase to 60% of ematocrit. This will cause an increase in the concentration of hemoglobin in the blood and hence an increase in capacity to carry oxygen blood. Searches have thus indicated that with the acclimation to high altitudes there is a significant increase in hemoglobin (Hb) and ematocrit (Hct), although these results may also suggest other ideas. In fact, acclimation to low oxygen causes a reduction in volume of the plasma and consequently an increase on the values of Hct, this process seems to be caused by a combination of factors, such as a loss of proteins from plasma, an increase of capillary permeability of dehydration and diuresis. It is good to stress that the physiological adaptations can counteract the increase in the share altitude up to about 5,000 meters over this threshold, in fact, alteration of functional fail to offset the imbalance due to the share altitude leading to a deterioration of the body, if exposed to long stay in high altitude. Another important element of the acclimation is to increase the heart rate to compensate with more beats per minute, the lesser availability of oxygen, while decreasing the systolic range, that is the amount of blood the heart pumps each beat. In this case it was shown that if a person has, at sea level, a maximum heart rate of 180 beats per minute, the quota of 5,000 meters can not exceed 160 beats per minute. It tries, then, to play these stimulus induced to the low oxygen through curtains lowoxygen-ipobaric. These facilities closed in which the athlete can stay for a few hours a day (usually the night) breathing air which has been artificially reduced the partial pressure of oxygen. Studies in this direction, however, have not yet unequivocally demonstrated the effectiveness of this practice is not all those who undergo this treatment respond in the same way and in many subjects has not been no changes at the level of increase red blood cells or erythropoietin, while in others, even brief exposures low oxygen (1.5 -2.0 hours) have proved sufficient to stimulate increased production of erythropoietin and consequently to increase red blood cells. However, it is shown that to get real increases in red blood cells must remain high for a period not less than 3 weeks and 10 hours a day, so it is hard to believe that a few hours of exposure in a tent low oxygen can play the same function with the same benefits, however, still has not managed to identify a "threshold", depending too much from the individual capacity of the individual genetic entity. Leaving stay low oxygen artificial exposures, however, remain high proportion of adequate duration, around six weeks, has shown it can produce a real increase in erythrocyte mass, albeit with some individual variability. For the purpose of enhancing athletic performance, however, was found involved other peripheral adaptations, such as increased capacity from the muscle tissue to extract and use oxygen; happens that is a real improvement in the ability to carry oxygen and use it in the suburbs. Regarding the effects on energy of metabolism, however, we can say that hypoxia causes a reduction of aerobic and anaerobic capacity, because the ability lattacid after a maximum effort in acute hypoxia, no change in sea level, but acclimation after suffering an apparent reduction. In addition to that already heights above the 2300 m, training support to the same intensity as those at sea level is virtually impossible. In preparing thus a period of training in high altitude will restore good deposits of iron and treat hydration to be higher than normal because of increased dehydration. Regarding the techniques then spent the studies have come to uniquely identify the best solution for improving blood values and benefits of sports, with a stay at high altitude (2,500 meters) and intensive training in average shares (1,250 meters), so as demonstrated observations of two control groups, one of which lived and trained constantly in high altitude and the other stayed in high altitude and train intensely to intermediate. Of course in cycling is more difficult to recreate this condition (studies have been conducted on athletes from athletics), but this does not mean that a stay in high altitude for a period of 6 weeks is not effective. Indeed, even the control group that was constantly at high altitude had also increased their blood values, but not athletic performance because of the training conducted at high altitude, which included a lower heart rate, oxygen consumption and a minor peak lactate.